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1.
Semina ciênc. agrar ; 44(2): 653-670, mar.-abr. 2023. tab, graf
Article in English | VETINDEX | ID: biblio-1434447

ABSTRACT

The food industry is very interested in high-yield ingredients to enrich and develop new products that have an affordable value for the population. This work aimed to determine the correlations and contrasts between grain physical and agronomic traits of conventional and transgenic corn hybrids cultivated in the first crop season. The experiments were installed in the 2017/18, 2018/19, and 2019/20 crop seasons in Guarapuava - PR. The experimental design was a randomized block design with eight hybrids (SUPREMO VIP, SUPREMO, P30F53VYH, P30F53, P3456H, P3456, DKB290PRO3, and DKB290) and three replications. The agronomic traits, such as the percentage of rot grains, 1000-grain mass, and grain yield, also the physical traits of grains for industrial purposes, such as grits, germ, vitreousness, flotation, and hectoliter weight, were evaluated. There is a positive correlation between grits and flotation. The choice of hybrids for the food industry based on vitreousness positively favors flotation. The grits showed a positive correlation with hectoliter weight and a negative correlation with the incidence of rot grains. Vitreousness was influenced by the choice of conventional or transgenic hybrid and crop season. The environments of the crop seasons influence the grain yield, 1000-grain mass, and rot grain incidence of conventional and transgenic corn hybrids.(AU)


A indústria de alimentos tem grande interesse por ingredientes de elevado rendimento industrial para enriquecer e desenvolver novos produtos, e que tenha um valor acessível para a população. Os objetivos desse trabalho foram determinar as correlações e contrastes entre caracteres físicos de grãos e agronômicos de híbridos de milho convencionais e transgênicos cultivados na primeira safra. Os experimentos foram instalados nas safras agrícolas (2017/18, 2018/19 e 2019/20), no município de Guarapuava ­ PR. O delineamento experimental utilizado foi o de blocos casualizados com 8 híbridos: (SUPREMO VIP, SUPREMO, P30F53VYH, P30F53, P3456H, P3456, DKB290PRO3, DKB290) e três repetições. Foram avaliadas as características agronômicas como a porcentagem de grãos ardidos, peso de mil grãos e produtividade de grãos e também as características físicas dos grãos para fins industriais, como a canjica, gérmen, vitreosidade, flutuação e peso hectolítrico. Há correlação positiva entre a canjica e a flutuação. A escolha de híbridos para a indústria alimentícia com base na vitreosidade favorece positivamente a característica de flutuação. A canjica apresentou correlação positiva com peso hectolitro e negativa com incidência de grãos ardidos. A vitreosidade foi influenciada pela escolha do híbrido convencional ou transgênico e pela safra agrícola. Os ambientes das safras agrícolas influenciam as características produtividade de grãos, peso de mil grãos e incidência de grãos ardidos dos híbridos de milho convencional e transgênico.(AU)


Subject(s)
Edible Grain/anatomy & histology , Food, Genetically Modified , Brazil , Zea mays/anatomy & histology , Collective Feeding
2.
Sci. agric ; 80: e20220016, 2023. tab, ilus
Article in English | VETINDEX | ID: biblio-1427829

ABSTRACT

Tomato genotypes ( Solanum spp.) have genetic variability of most desirable features, such as resistance to biotic and abiotic stresses. However, incompatibility of crosses of wild genotypes with domesticated tomatoes, or even between wild genotypes, hinders the breeding process. Thus, knowledge of the reproductive biology of genotypes and conditions is necessary to maximize the success of artificial crossings. This study evaluated the compatibility of self-pollination, intra- and interspecific controlled crosses, stigma receptivity, and pollen viability in tomato genotypes. We used two commercial genotypes S. lycopersicum ('RVTM08' and 'Redenção') and seven accessions of wild tomato genotypes ('AF 26970', 'LA-1401', 'AF 19684', 'LA-1967', 'PI-127826', 'PI-134417', and 'LA-716'). We evaluated all crosses and their reciprocals, besides the self-pollinations. The variables evaluated were fruit index (FI), number of seeds per fruit (SN), and seed germination percentage (GP). Stigma receptivity and grains' pollen viability index (PVI) were also assessed. The results showed that 'LA-1967' was self-incompatible, had a low PVI, and generated fruit without seeds in most crosses. As female parents, 'RVTM08', 'Redenção', 'AF 26970', 'LA-1401', and 'AF 19684' showed higher FI and SN. There was a wide diversity of reproductive characteristics between the genotypes and crosses that did not influence GP. Compatibility of crosses in tomatoes is determined by the female parent choice and can be affected by stigma receptivity and the PVI.(AU)


Subject(s)
Solanum lycopersicum/physiology , Pollination , Self-Fertilization , Seeds/physiology
3.
Sci Rep ; 12(1): 15284, 2022 Sep 10.
Article in English | MEDLINE | ID: mdl-36088482

ABSTRACT

Soybean and maize are some of the main drivers of Brazilian agribusiness. However, biotic and abiotic factors are of great concern, causing huge grain yield and quality losses. Phosphorus (P) deficiency is important among the abiotic factors because most Brazilian soils have a highly P-fixing nature. Thus, large amounts of phosphate fertilizers are regularly applied to overcome the rapid precipitation of P. Searching for alternatives to improve the use of P by crops is essential to reduce the demand for P input. The use of multifunctional rhizobacteria can be considered one of these alternatives. In this sense, the objective of the present work was to select and validate bacterial strains with triple action (plant growth promoter, phosphate solubilizer, and biocontrol agent) in maize and soybean, aiming to develop a multifunctional microbial inoculant for Brazilian agriculture. Bacterial strains with high indole acetic acid (IAA) production, phosphate solubilization, and antifungal activity against soil pathogenic fungi (Rhizoctonia solani, Macrophomina phaseolina, and Fusarium solani) were selected from the maize rhizosphere. Then, they were evaluated as growth promoters in maize under greenhouse conditions. Based on this study, strain 03 (Ag75) was selected due to its high potential for increasing biomass (root and shoot) and shoot P content in maize. This strain was identified through genomic sequencing as Bacillus velezensis. In field experiments, the inoculation of this bacterium increased maize and soybean yields by 17.8 and 26.5%, respectively, compared to the control (25 kg P2O5). In addition, the inoculation results did not differ from the control with 84 kg P2O5, indicating that it is possible to reduce the application of phosphate in these crops. Thus, the Ag75 strain has great potential for developing a multifunctional microbial inoculant that combines the ability to solubilize phosphate, promote plant growth, and be a biocontrol agent for several phytopathogenic fungi.


Subject(s)
Agricultural Inoculants , Bacillus , Bacillus/genetics , Bacteria/genetics , Crops, Agricultural , Phosphates , Glycine max , Zea mays
4.
Microorganisms ; 10(7)2022 Jul 12.
Article in English | MEDLINE | ID: mdl-35889120

ABSTRACT

Increasing phosphorus (P) use efficiency in agricultural systems is urgent and essential to significantly reduce the global demand for this nutrient. Applying phosphate-solubilizing and plant growth-promoting bacteria in the rhizosphere represents a strategy worthy of attention. In this context, the present work aimed to select and validate bacterial strains capable of solubilizing phosphorous and promoting maize growth, aiming to develop a microbial inoculant to be used in Brazilian agriculture. Bacterial strains from the maize rhizosphere were evaluated based on their ability to solubilize phosphate and produce indole acetic acid. Based on these characteristics, 24 strains were selected to be further evaluated under laboratory, greenhouse, and field conditions. Among the selected strains, four (I04, I12, I13, and I17) showed a high potential to increase maize root growth and shoot P content. Strains I13 (Ag87) and I17 (Ag94) were identified by genomic sequencing as Bacillus megaterium and Lysinibacillus sp., respectively. These strains presented superior yield increments relative to the control treatment with 30% P. In addition, combining Ag87 and Ag94 resulted in even higher yield gains, indicating a synergistic effect that could be harnessed in a commercial inoculant for Brazilian agriculture.

5.
Ciênc. rural (Online) ; 52(9): e20210286, 2022. tab, graf
Article in English | VETINDEX | ID: biblio-1360359

ABSTRACT

The analysis of main additive effects and multiplicative interaction is commonly used in the evaluation of the genotype x environment interaction, however, its application can be used for other purposes, as it is performed in the presentresearch, which uses this technique in the selection of inbred lines, testers and hybrids in maize topcrosses. Thisresearch determined the effect of the inbred lines x testers interaction through the analysis of main additive effects and multiplicative interaction, verifying their efficiency in the selection of inbred lines, testers and hybrid combinations in topcrosses. The trials were carried out in the 2015/16 and 2016/17 crop seasons, with a complete block design, with three replications. Thirty S3 maize inbred lines were evaluated in crosses with the AG8025, P30B39, MLP102, 60.H23.1 and 70.H26.1 testers forming 150 hybrids topcrosses. The trait evaluated was grain yield. The adaptability and stability of testers and inbred lines were evaluated by the methodology of analysis of main additive effects and multiplicative interaction directed to the interaction of testers x inbred lines. The 96.3 inbred line has the most homogeneous performance and the highest grain yield, considering the crossing with all testers in both environments. The 70.H26.1 tester is considered the most stable and the most recommended for topcrosses. The best specific combinations were 96.3 x 70.H26.1 and 96.3 x 60.H23.1.


A análise dos principais efeitos aditivos e interação multiplicativa é comumente utilizada na avaliação da interação genótipo x ambiente, porém, sua aplicação pode ser estendida para outros propósitos assim como realizado no presente trabalho em que utiliza esta técnica na seleção de linhagens, testadores e híbridos em topcrosses de milho. O objetivo deste trabalho foi determinar o efeito da interação linhagens x testadores por meio da análise dos principais efeitos aditivos e da interação multiplicativa, verificando sua eficiência na seleção de linhagens, testadoras e combinações híbridas em topcrosses. Os ensaios foram realizados nas safras 2015/16 e 2016/17, com delineamento em blocos completos, com três repetições. Trinta linhagens de milho S3 foram avaliadas em cruzamentos com os testadores AG8025, P30B39, MLP102, 60.H23.1 e 70.H26.1 formando 150 topcrosses híbridos. A característica avaliada foi a produtividade de grãos. A adaptabilidade e estabilidade de testadores e linhagens foram avaliadas pela metodologia de análise de efeitos aditivos principais e interação multiplicativa direcionada à interação testadores x linhagens. A linhagem 96.3 apresentou o desempenho mais homogêneo e o maior rendimento de grãos, considerando o cruzamento com todos os testadores em ambos os ambientes. O testador 70.H26.1 é considerado o mais estável e o mais recomendado para topcrosses. As melhores combinações específicas foram 96.3 x 70.H26.1 e 96.3 x 60.H23.1.


Subject(s)
Zea mays/growth & development , Zea mays/genetics , Plant Breeding/methods
6.
Rev. bras. zootec ; 51: e20200180, 2022. graf, tab
Article in English | VETINDEX | ID: biblio-1442842

ABSTRACT

The objective of this study was to evaluate the effect of harvesting corn at different maturity stages for silage production combined with four storage periods, considering nutrient loss and the chemical composition of silage of the whole plant and also of grainless plants. The experiment was performed in a completely randomized design with a factorial arrangement of six maturity stages of corn [reproductive (R); R1 to R6] and four periods of silage storage (30, 60, 90, and 120 days). At stages R1 and R2, losses by effluents occurred more intensely when compared with the more advanced stages, whereas losses by gases showed the opposite behavior, with stage R6 responsible for the greatest losses. Stage R4 showed a stable dry matter (DM) content during the storage period, 42.08%, and had the lowest levels of neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) for the whole plant silage. The ADL in the silage of grainless plant of stage R4 was not the lowest, but it was close to the first reproductive stages, being an important point, since the first reproductive stages can present a vegetative fraction of better quality. The highest DM volumes produced by area occurred in the most advanced stages; however, R5 obtained a greater reduction in volume over the days of storage (20.66 kg day−1). The production cost was lower at the advanced stages (R4, R5, and R6) when compared with the first reproductive stages (R1, R2, and R3), and in general, during the storage period the costs did not have great variations. Based on the chemical composition of the silages, DM losses during the storage period, the stability in the costs of DM ton over the days of storage, the R4 stage was the most suitable for silage production.(AU)


Subject(s)
Silage , Edible Grain/chemistry , Zea mays/chemistry , Fermentation
7.
Front Genet ; 12: 637133, 2021.
Article in English | MEDLINE | ID: mdl-34539725

ABSTRACT

Genomic-assisted breeding has become an important tool in soybean breeding. However, the impact of different genomic selection (GS) approaches on short- and long-term gains is not well understood. Such gains are conditional on the breeding design and may vary with a combination of the prediction model, family size, selection strategies, and selection intensity. To address these open questions, we evaluated various scenarios through a simulated closed soybean breeding program over 200 breeding cycles. Genomic prediction was performed using genomic best linear unbiased prediction (GBLUP), Bayesian methods, and random forest, benchmarked against selection on phenotypic values, true breeding values (TBV), and random selection. Breeding strategies included selections within family (WF), across family (AF), and within pre-selected families (WPSF), with selection intensities of 2.5, 5.0, 7.5, and 10.0%. Selections were performed at the F4 generation, where individuals were phenotyped and genotyped with a 6K single nucleotide polymorphism (SNP) array. Initial genetic parameters for the simulation were estimated from the SoyNAM population. WF selections provided the most significant long-term genetic gains. GBLUP and Bayesian methods outperformed random forest and provided most of the genetic gains within the first 100 generations, being outperformed by phenotypic selection after generation 100. All methods provided similar performances under WPSF selections. A faster decay in genetic variance was observed when individuals were selected AF and WPSF, as 80% of the genetic variance was depleted within 28-58 cycles, whereas WF selections preserved the variance up to cycle 184. Surprisingly, the selection intensity had less impact on long-term gains than did the breeding strategies. The study supports that genetic gains can be optimized in the long term with specific combinations of prediction models, family size, selection strategies, and selection intensity. A combination of strategies may be necessary for balancing the short-, medium-, and long-term genetic gains in breeding programs while preserving the genetic variance.

8.
J Econ Entomol ; 113(3): 1493-1503, 2020 06 06.
Article in English | MEDLINE | ID: mdl-32249292

ABSTRACT

Rhopalosiphum padi L. is one of the predominant aphids affecting wheat crops worldwide. Therefore, the identification of resistant genotypes and the understanding of molecular response mechanisms involved in wheat resistance to this aphid may contribute to the development of new breeding strategies. In this study, we evaluated the resistance of 15 wheat cultivars to R. padi and performed morpho-histological and gene expression analyses of two wheat cultivars (BRS Timbaúva, resistant and Embrapa 16, susceptible) challenged and unchallenged by R. padi. The main findings of our work are as follows: 1) most Brazilian wheat cultivars recently released are resistant to R. padi; 2) Green leaf volatiles are probably involved in the resistance of the BRS Timbaúva cultivar to the aphid; 3) trichomes were more abundant and larger in the resistant cultivar; 4) the internal morphology did not show differences between cultivars; 5) the lipoxygenase-encoding gene was downregulated in the susceptible cultivar and basal expression remained level in the resistant cultivar; and 6) the expression of resistance-related proteins was induced in the resistant but not in the susceptible cultivar. Lipoxygenase is the first enzyme in the octadecanoic pathway, a well-known route for the synthesis of signaling molecules involved in the activation of plant defense. The overall analyses suggest that the key steps in BRS Timbaúva resistance to R. padi may be presence or absence of green leaf volatiles decreasing the aphid preference and the action of nonglandular trichome as a physical barrier, which allows continuous lipoxygenase-encoding gene expression.


Subject(s)
Aphids , Animals , Aphids/genetics , Brazil , Breeding , Plant Leaves , Triticum/genetics
9.
Semina ciênc. agrar ; 41(06,supl. 2): 3285-3298, 2020. tab
Article in English | VETINDEX | ID: biblio-1501686

ABSTRACT

The objective of this study was to evaluate the effect of foliar fungicide application on the chemical characteristics and in situ digestibility of forage and silage in forage maize hybrids with different grain textures in two sowing seasons. A randomized complete block design was used with four replications, in a 4 x 2 factorial arrangement, 4 hybrids, with and without foliar fungicide application, in two sowing seasons. The hybrids used were DKB240PRO, AS1572PRO, 32R48YH and AG8690PRO3. Data were tested by analysis of variance; the means were compared by Tukey’s test at 5% probability and two non orthogonal contrasts were performed. The application of fungicide on forage maize hybrids reduced the content of neutral detergent fiber (NDF), acid detergent fiber (ADF), soft dough stage and in the silage produced. The sowing season in December negatively influenced the chemical parameters of forage maize hybrids, compared to sowing in October. Hybrids with highly vitreous endosperm presented the highest contents of NDF and ADF, soft dough stage and in the silage produced. The application of fungicide (trifloxystrobin + prothioconazole) at the V8 and R1 stages positively influenced in situ digestibility soft dough stage and in the silage produced, depending of the sowing season.


O objetivo foi avaliar o efeito da aplicação foliar de fungicida sobre as características bromatológicas e digestibilidade in situ de forragem e silagem em híbridos de milho forrageiro com diferentes texturas de grãos em duas épocas de semeadura. O delineamento foi blocos casualizados, em esquema fatorial4x2, 4 híbridos, sem e com aplicação de fungicida, em duas épocas de semeadura. Os híbridos utilizados foram DKB240PRO, AS1572PRO, 32R48YH e AG8690PRO3. Os dados obtidos foram submetidos à análise de variância, as médias comparadas pelo teste de Tukey e realizados dois contrastes não ortogonais. A aplicação de fungicida em híbridos de milho forrageiros reduziu os teores de fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) obtidos no ponto de forragem e na silagem produzida. A época de semeadura em dezembro influenciou negativamente os parâmetros bromatológicos de híbridos de milho forrageiros, em comparação com a semeadura em outubro. Os híbridos de endosperma de alta vitreosidade obtiveram os maiores teores de FDN e FDA, no ponto de forragem e na silagem produzida. A aplicação de fungicida (trifloxostrobina + protioconazol) em V8e R1 influenciou positivamente a digestibilidade in situ no ponto de forragem e na silagem produzida, independente da época de semeadura.


Subject(s)
Fungicides, Industrial/administration & dosage , Fungicides, Industrial/adverse effects , Silage/analysis , Silage/toxicity , Zea mays/drug effects , Zea mays/chemistry , Zea mays/toxicity
10.
Semina Ci. agr. ; 41(06,supl. 2): 3285-3298, 2020. tab
Article in English | VETINDEX | ID: vti-32581

ABSTRACT

The objective of this study was to evaluate the effect of foliar fungicide application on the chemical characteristics and in situ digestibility of forage and silage in forage maize hybrids with different grain textures in two sowing seasons. A randomized complete block design was used with four replications, in a 4 x 2 factorial arrangement, 4 hybrids, with and without foliar fungicide application, in two sowing seasons. The hybrids used were DKB240PRO, AS1572PRO, 32R48YH and AG8690PRO3. Data were tested by analysis of variance; the means were compared by Tukeys test at 5% probability and two non orthogonal contrasts were performed. The application of fungicide on forage maize hybrids reduced the content of neutral detergent fiber (NDF), acid detergent fiber (ADF), soft dough stage and in the silage produced. The sowing season in December negatively influenced the chemical parameters of forage maize hybrids, compared to sowing in October. Hybrids with highly vitreous endosperm presented the highest contents of NDF and ADF, soft dough stage and in the silage produced. The application of fungicide (trifloxystrobin + prothioconazole) at the V8 and R1 stages positively influenced in situ digestibility soft dough stage and in the silage produced, depending of the sowing season.(AU)


O objetivo foi avaliar o efeito da aplicação foliar de fungicida sobre as características bromatológicas e digestibilidade in situ de forragem e silagem em híbridos de milho forrageiro com diferentes texturas de grãos em duas épocas de semeadura. O delineamento foi blocos casualizados, em esquema fatorial4x2, 4 híbridos, sem e com aplicação de fungicida, em duas épocas de semeadura. Os híbridos utilizados foram DKB240PRO, AS1572PRO, 32R48YH e AG8690PRO3. Os dados obtidos foram submetidos à análise de variância, as médias comparadas pelo teste de Tukey e realizados dois contrastes não ortogonais. A aplicação de fungicida em híbridos de milho forrageiros reduziu os teores de fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) obtidos no ponto de forragem e na silagem produzida. A época de semeadura em dezembro influenciou negativamente os parâmetros bromatológicos de híbridos de milho forrageiros, em comparação com a semeadura em outubro. Os híbridos de endosperma de alta vitreosidade obtiveram os maiores teores de FDN e FDA, no ponto de forragem e na silagem produzida. A aplicação de fungicida (trifloxostrobina + protioconazol) em V8e R1 influenciou positivamente a digestibilidade in situ no ponto de forragem e na silagem produzida, independente da época de semeadura.(AU)


Subject(s)
Zea mays/drug effects , Zea mays/chemistry , Zea mays/toxicity , Silage/analysis , Silage/toxicity , Fungicides, Industrial/administration & dosage , Fungicides, Industrial/adverse effects
11.
Semina Ci. agr. ; 39(1): 29-38, jan.-fev. 2018. tab, graf
Article in English | VETINDEX | ID: vti-728490

ABSTRACT

Resistance of maize inbred lines to major leaf diseases should be characterized for the development of new hybrids in breeding programs. Thus, this study aimed to assess the severity of leaf diseases in maize inbredlines with different kernel hardnessand two sowingseasons. We assessed four inbred lines and one check hybrid with dent kernels and four inbred lines and a check hybrid with flint kernels. Treatments were conducted in two sowing seasons, one in October, and another in December 2013. The symptoms of gray leaf spot (Cercospora zeae-maydis), northern leaf blight (Exserohilum turcicum), and white leaf spot (a complex of Phaeosphaeria maydis and Pantoea ananatis) were assessed every 10 days from flowering. The area under the disease progress curve was also calculated. Severity level of the diseases was higher in inbred lines when compared to the check hybrds (AG8041 PRO and P30R50YH), regardless of kernel hardness. Dent-kernel inbred lines showed a higher severity of northern leaf blight symptoms when compared to flint-kernelones. It is worth mentioning that disease severity increased as sowing was delayed.(AU)


A caracterização de linhagens de milho quanto à resistência às principais doenças é fundamental para o desenvolvimento de novos híbridos em programas de melhoramento. Assim, o objetivo deste trabalho foi avaliar a severidade de doenças foliares em linhagens de milho com diferentes texturas de grãos em duas épocas de semeadura. Foram avaliadas quatro linhagens e um híbrido testemunha com grãos dentados e quatro linhagens e um híbrido testemunha com grãos duros. Os tratamentos foram conduzidos em duas épocas de semeadura, em outubro e em dezembro de 2013. A partir do florescimento, a cada 10 dias, foram avaliadas as doenças foliares cercosporiose (Cercospora zeae-maydis), helmintosporiose (Exserohilum turcicum) e mancha branca (complexo Phaeosphaeria maydis/Pantoea ananatis). Foi calculada a área abaixo da curva do progresso das doenças (AACPD). A severidade das doenças foi maior nas linhagens, comparativamente aos híbridos testemunhas AG8041 PRO e P30R50YH, independentemente da textura dos grãos. As linhagens de textura dentada apresentaram maior severidade de sintomas da helmintosporiose, quando comparada às linhagens de grãos duros. Houve aumento da severidade das doenças avaliadas com o atraso da semeadura.(AU)


Subject(s)
Plant Diseases , Zea mays , Crops, Agricultural , Edible Grain , 24444
12.
Semina ciênc. agrar ; 39(1): 29-38, jan.-fev. 2018. tab, graf
Article in English | VETINDEX | ID: biblio-1501081

ABSTRACT

Resistance of maize inbred lines to major leaf diseases should be characterized for the development of new hybrids in breeding programs. Thus, this study aimed to assess the severity of leaf diseases in maize inbredlines with different kernel hardnessand two sowingseasons. We assessed four inbred lines and one check hybrid with dent kernels and four inbred lines and a check hybrid with flint kernels. Treatments were conducted in two sowing seasons, one in October, and another in December 2013. The symptoms of gray leaf spot (Cercospora zeae-maydis), northern leaf blight (Exserohilum turcicum), and white leaf spot (a complex of Phaeosphaeria maydis and Pantoea ananatis) were assessed every 10 days from flowering. The area under the disease progress curve was also calculated. Severity level of the diseases was higher in inbred lines when compared to the check hybrds (AG8041 PRO and P30R50YH), regardless of kernel hardness. Dent-kernel inbred lines showed a higher severity of northern leaf blight symptoms when compared to flint-kernelones. It is worth mentioning that disease severity increased as sowing was delayed.


A caracterização de linhagens de milho quanto à resistência às principais doenças é fundamental para o desenvolvimento de novos híbridos em programas de melhoramento. Assim, o objetivo deste trabalho foi avaliar a severidade de doenças foliares em linhagens de milho com diferentes texturas de grãos em duas épocas de semeadura. Foram avaliadas quatro linhagens e um híbrido testemunha com grãos dentados e quatro linhagens e um híbrido testemunha com grãos duros. Os tratamentos foram conduzidos em duas épocas de semeadura, em outubro e em dezembro de 2013. A partir do florescimento, a cada 10 dias, foram avaliadas as doenças foliares cercosporiose (Cercospora zeae-maydis), helmintosporiose (Exserohilum turcicum) e mancha branca (complexo Phaeosphaeria maydis/Pantoea ananatis). Foi calculada a área abaixo da curva do progresso das doenças (AACPD). A severidade das doenças foi maior nas linhagens, comparativamente aos híbridos testemunhas AG8041 PRO e P30R50YH, independentemente da textura dos grãos. As linhagens de textura dentada apresentaram maior severidade de sintomas da helmintosporiose, quando comparada às linhagens de grãos duros. Houve aumento da severidade das doenças avaliadas com o atraso da semeadura.


Subject(s)
Plant Diseases , Crops, Agricultural , Zea mays , 24444 , Edible Grain
13.
Semina Ci. agr. ; 38(5): 2899-2908, Set.-Out. 2017. tab, graf
Article in English | VETINDEX | ID: vti-24949

ABSTRACT

Commercial hybrids are viable to generate base populations for obtaining new superior lines. Therefore, this study aimed to evaluate the performance and stability of maize topcross hybrids and select superior partly inbred lines. We evaluated 155 topcross hybrids of partly inbred lines crossed with an elite inbred line (tester) together with 14 commercial hybrids (2B688, AG7088, AS1575, DKB390, GNZ2005, GNZ8132, GNZ9501, GNZ9505, GNZ9548, GNZ9623, P30F35, P30F53, P30R50, and Penta) in Guarapuava-PR, Candói-PR, Guarda-Mor-MG, and Paracatu-MG (Brazil). The assessed variable was grain yield (GY), in kg ha-1, at 13% moisture, being the plant stand corrected by covariance method. A variance analysis was carried out, testing both stability and adaptability. There were significant differences for all sources of variation. By considering the GY means of the genotypes in each environment, Candói (10,985 kg ha-1) and Paracatu (10,917 kg ha-1) were in the first group, while Guarda-Mor (10,448 kg ha-1) was allocated in the intermediate group, and Guarapuava (10,159 kg ha-1) formed the group of lower GY means. None of the topcrosses stood out in any of the four environments, which may be related to the differences in climate and altitude between environments. Despite of this fact, lines 9, 13, 39, 40, 60, 93, 108, 179, 184, 189, 194, 211, 212, 213, 216, 217, 235, 243, 245, and 253 excelled as promising and should follow the process of inbreeding, in addition to the topcrosses 87, 144, 179, and 211, which also stood out for stability and adaptability in these environments.(AU)


Os híbridos comerciais são viáveis para gerar populações-base para obter novas linhagens superiores. Portanto, o objetivo deste trabalho foi avaliar o desempenho e estabilidade de híbridos topcrosses de milho e selecionar híbridos superiores e/ou linhagens parcialmente endogâmicas com potencial superior. Foram avaliadas 155 linhagens parcialmente endogâmicas em cruzamentos topcrosses com uma linhagem elite (testador) juntamente com 14 híbridos comerciais (2B688, AG7088, AS1575, DKB390, GNZ2005, GNZ8132, GNZ9501, GNZ9505, GNZ9548, GNZ9623, P30F35, P30F53, P30R50 e Penta) em Guarapuava-PR, Candói-PR, Guarda-Mor-MG e Paracatu-MG. Foi avaliado a produtividade de grãos (GY) em kg ha-1 com 13% de umidade em que o estande de plantas foi corrigido pelo método da covariância. Fez-se análise de variância dos dados e de estabilidade e adaptabilidade. Houve efeito significativo para todas as fontes de variação. Considerando a média de GY em kg ha-1 dos genótipos em cada ambiente, Candói (10,985 kg ha-1) e Paracatu (10,917 kg ha-1) foram alocados no primeiro grupo, enquanto Guarda-mor (10,448 kg ha-1) foi alocado no grupo intermediário e Guarapuava (10,159 kg ha-1) formou o pior grupo de médias. Não houve híbridos topcrosses que se destacaram nos quatro ambientes. Apesar deste fato, as linhagens 9, 13, 39, 40, 60, 93, 108, 179, 184, 189, 194, 211, 212, 213, 216, 217, 235, 243, 245 e 253 são promissoras e devem seguir no programa de melhoramento no processo de endogamia e os híbridos topcrosses 87, 144, 179 e 211 também se destacam por estar entre os melhores em mais de dois ambientes, sendo estáveis e adaptados e podem ser utilizados para cultivo nestes ambientes.(AU)


Subject(s)
Zea mays/chemistry , Zea mays/genetics , Genetic Enhancement , Plant Breeding , Compliance
14.
Semina ciênc. agrar ; 38(5): 2899-2908, 2017. tab, graf
Article in English | VETINDEX | ID: biblio-1500987

ABSTRACT

Commercial hybrids are viable to generate base populations for obtaining new superior lines. Therefore, this study aimed to evaluate the performance and stability of maize topcross hybrids and select superior partly inbred lines. We evaluated 155 topcross hybrids of partly inbred lines crossed with an elite inbred line (tester) together with 14 commercial hybrids (2B688, AG7088, AS1575, DKB390, GNZ2005, GNZ8132, GNZ9501, GNZ9505, GNZ9548, GNZ9623, P30F35, P30F53, P30R50, and Penta) in Guarapuava-PR, Candói-PR, Guarda-Mor-MG, and Paracatu-MG (Brazil). The assessed variable was grain yield (GY), in kg ha-1, at 13% moisture, being the plant stand corrected by covariance method. A variance analysis was carried out, testing both stability and adaptability. There were significant differences for all sources of variation. By considering the GY means of the genotypes in each environment, Candói (10,985 kg ha-1) and Paracatu (10,917 kg ha-1) were in the first group, while Guarda-Mor (10,448 kg ha-1) was allocated in the intermediate group, and Guarapuava (10,159 kg ha-1) formed the group of lower GY means. None of the topcrosses stood out in any of the four environments, which may be related to the differences in climate and altitude between environments. Despite of this fact, lines 9, 13, 39, 40, 60, 93, 108, 179, 184, 189, 194, 211, 212, 213, 216, 217, 235, 243, 245, and 253 excelled as promising and should follow the process of inbreeding, in addition to the topcrosses 87, 144, 179, and 211, which also stood out for stability and adaptability in these environments.


Os híbridos comerciais são viáveis para gerar populações-base para obter novas linhagens superiores. Portanto, o objetivo deste trabalho foi avaliar o desempenho e estabilidade de híbridos topcrosses de milho e selecionar híbridos superiores e/ou linhagens parcialmente endogâmicas com potencial superior. Foram avaliadas 155 linhagens parcialmente endogâmicas em cruzamentos topcrosses com uma linhagem elite (testador) juntamente com 14 híbridos comerciais (2B688, AG7088, AS1575, DKB390, GNZ2005, GNZ8132, GNZ9501, GNZ9505, GNZ9548, GNZ9623, P30F35, P30F53, P30R50 e Penta) em Guarapuava-PR, Candói-PR, Guarda-Mor-MG e Paracatu-MG. Foi avaliado a produtividade de grãos (GY) em kg ha-1 com 13% de umidade em que o estande de plantas foi corrigido pelo método da covariância. Fez-se análise de variância dos dados e de estabilidade e adaptabilidade. Houve efeito significativo para todas as fontes de variação. Considerando a média de GY em kg ha-1 dos genótipos em cada ambiente, Candói (10,985 kg ha-1) e Paracatu (10,917 kg ha-1) foram alocados no primeiro grupo, enquanto Guarda-mor (10,448 kg ha-1) foi alocado no grupo intermediário e Guarapuava (10,159 kg ha-1) formou o pior grupo de médias. Não houve híbridos topcrosses que se destacaram nos quatro ambientes. Apesar deste fato, as linhagens 9, 13, 39, 40, 60, 93, 108, 179, 184, 189, 194, 211, 212, 213, 216, 217, 235, 243, 245 e 253 são promissoras e devem seguir no programa de melhoramento no processo de endogamia e os híbridos topcrosses 87, 144, 179 e 211 também se destacam por estar entre os melhores em mais de dois ambientes, sendo estáveis e adaptados e podem ser utilizados para cultivo nestes ambientes.


Subject(s)
Genetic Enhancement , Plant Breeding , Zea mays/genetics , Zea mays/chemistry , Compliance
15.
Semina Ci. agr. ; 36(4): 2395-2406, jul.-ago. 2015. tab
Article in Portuguese | VETINDEX | ID: vti-30272

ABSTRACT

O objetivo do trabalho foi avaliar o comportamento relativo de 74 linhagens parcialmente endogâmicas (S4) provenientes do cruzamento entre os híbridos comerciais P30P70 e Dow8460 em topcrosses com o híbrido simples comercial P30F53 (testador), mais as testemunhas (híbridos Dow8460, P30F53 e Status). A produtividade de grãos (PG) foi avaliada em dois ambientes em Guarapuava-PR. Houve efeito significativo de genótipos, ambientes e da interação genótipos x ambientes quanto à produtividade de grãos (PG). Entre os híbridos topcrosses (HTC) a PG variou de 8.302 (HTC 123, no ambiente 2) a 14.809 kg ha-1 (HTC 11, no ambiente 1). No ambiente 1 foram avaliadas características agronômicas da forragem e bromatológicas da silagem. A produtividade de massa verde (PMV) da forragem variou de 49.857 (HTC 208) a 80.642 kg ha-1 (HTC 22) e a produtividade de massa seca (PMS) variou de 11.072 (HTC 217) a 24.143 kg ha-1 (HTC 22). Os teores de fibra em detergente neutro (FDN) variaram de 45,39 (HTC 80) a 56,71% (HTC 77) e os teores de fibra em detergente ácido (FDA) variaram de 25,45 (HTC 80) a 35,60% (HTC 99). Para o valor relativo da silagem (VRS) foram obtidos índices médios variando de 103 (HTC 148) à 142 (HTC 80). Para todos os caracteres houve topcrosses que não diferiram das melhores testemunhas. Os HTC 22 e 53 foram superiores considerando todo o conjunto de caracteres forrageiros e...(AU)


The objective of this study was to evaluate the relative performance of 74 partially inbred lines (S4) from crosses between the commercial hybrids P30P70 and Dow8460 in topcrosses with the commercial single cross hybrid P30F53 (tester), and checks (hybrids Dow8460, P30F53 and Status). The grain yield (GY) was evaluated in two environments in Guarapuava-PR. The effects of genotypes, environments and genotypes x environments interaction were significant for grain yield (GY). Among the topcrosses hybrids (TCH) the GY ranged from 8,302 (TCH 123, in the environment 2) to 14,809 kg ha-1 (TCH 11, in the environment 1). In the environment 1 we evaluated agronomic characteristics of the forage and bromatologic characteristics of the silage. The green mass productivity (GMP) of forage ranged from 49,857 (TCH 208) to 80,642 kg ha-1 (TCH 22) and the dry mass productivity (DMP) ranged from 11,072 (TCH 217) to 24,143 kg ha-1 (TCH 22). The contents of neutral detergent fiber (NDF) ranged from 45.39 (TCH 80) to 56.71% (TCH 77) and the contents of acid detergent fiber (ADF) ranged from 25.45 (TCH 80) to 35 60% (TCH 99). The relative value of the silage (RVS) presented average ratios ranged from 103 (TCH 148) to 142 (TCH 80). For all the characteristics many topcrosses did not differ from the best checks. TCH 22 and 53 were higher considering the set of all characteristics of forage and silage...(AU)


Subject(s)
Zea mays/growth & development , Zea mays/genetics , Plant Breeding , Hybridization, Genetic
16.
Semina Ci. agr. ; 36(2): 917-932, mar.-abr. 2015. tab
Article in Portuguese | VETINDEX | ID: vti-30244

ABSTRACT

O experimento foi conduzido no Núcleo de Produção Animal (NUPRAN) da Universidade Estadual do Centro Oeste (UNICENTRO), com o objetivo de avaliar o efeito da colheita da planta de milho em diferentes estádios reprodutivos e com diferentes processamentos de grãos sobre as perdas e o valor nutritivo das silagens. Diferenças (P 0,05) foram evidenciadas para o quesito estádio reprodutivo, quanto aos teores de matéria seca (26,70% contra 34,78%), matéria mineral (4,35% contra 3,87%), fibra em detergente ácido (32,63% contra 23,36%) e fibra em detergente neutro (52,06% contra 42,07%), respectivamente para os estádios grão pastoso (R3) e grão duro (R5). Elevadas perdas de matéria seca foram encontradas no estádio R3, sendo estas nas dimensões de 14,59% e 20,06%, respectivamente para as silagens com e sem processador de grãos. Quanto ao parâmetro de perdas de proteína bruta, não foram evidenciadas diferenças significativas para os efeitos isolados ou associados dos estádios de colheita e processamento do grão na silagem de milho. Elevadas diferenças podem ser percebidas quanto às perdas de fibra em detergente neutro e perdas de fibra em detergente ácido das silagens, justificado pelo aumento nos teores de fibra em detergente ácido na proporção média de 22,96% nas silagens colhidas no estádio R3 e redução nos seus teores com média de 4,60%, para o estádio R5. Não observou-se...(AU)


The aim of this study was evaluate the harvest of corn plant in different reproductive stages and different processing grain about losses and nutritive value of silages. Significant differences in the stage of harvest showed up in lower (P 0.05) for dry matter (26.70% against 34.78%) and higher values for contents of mineral matter (4.35 % against 3.87%), acid detergent fiber (32.63% vs. 23.36%) and neutral detergent fiber (52.06% against 42.07%) in the level of harvest dough (R3 ) compared to the level of hard grain (R5), respectively. High dry matter losses were found at stage R3, which are the dimensions of 14.59% and 20.06% respectively to silages with and without grain processor, significantly different (P> 0.05) results found for the R5 stage, which had an average loss of around 5.77%, demonstrating that silage harvested at R5 stage, allow greater dry matter recovery and hence greater savings for the farmer. Regarding the parameter of losses of crude protein, there were no significant differences for the effects of isolated or associated stages of harvesting and processing of grain in corn silage. Large differences can be perceived as the loss of neutral detergent fiber and loss of acid detergent fiber silage, justified by the increase in the levels of acid detergent fiber in the average share of 22.96% in the silage harvested at stage R3 and reduction in their...(AU)


Subject(s)
Zea mays/growth & development , Silage , Plant Development , Nutritive Value
17.
Semina Ci. agr. ; 36(1): 123-134, Jan.-Fev. 2015. tab
Article in Portuguese | VETINDEX | ID: vti-25401

ABSTRACT

Seven commercial maize hybrids (AS1575, 2B688, Penta, GNZ2004, AG8021, Sprint e P30F53) were intercrossed in a complete diallel, excluded reciprocal, obtaining 21 crosses. The 28 treatments were evaluated in two environments characterized by different densities (62,500 and 90,000 plants ha-1), with the aim of selecting the most promising parents for generating base population to obtain lines. Two experiments were carried out in Guarapuava-PR, at randomized block design with three replications. We estimated the general (GCA) and specific (SCA) combining abilities for yield and disease severity assessed by the area under the common rust (Puccinia sorghi) progress curve (AURPC) and the area under the leaf spot (Cercospora zeae-maydis) progress curve (AULPC). The effects of GCA and SCA were significant for grain yield and diseases severity in both densities, revealing the importance of both additive and non-additive effects. There GCA x densities interaction was significant only for grain yield. Crossings P30F53 x AG8021 and P30F53 x Penta had negative estimates of SCA for AURPC and AULPC on the environments average. Hybrids GNZ 2004 and P30F53 stood out showing positive GCA for grain yield and negative for AURPC and AULPC in both densities and therefore are recommended for generating base populations for obtaining lines adapted for both densities, conventional and denser plantings, given the current trends in management of maize.(AU)


Sete híbridos comerciais de milho (AS1575, 2B688, Penta, GNZ2004, AG8021, Sprint e P30F53) foram utilizados como genitores de um dialelo completo, sem os recíprocos, gerando 21 cruzamentos. Os 28 tratamentos foram avaliados em duas densidades populacionais (62.500 e 90.000 plantas ha-1), com o objetivo de selecionar os genitores mais promissores para a geração de populações-base para a obtenção de linhagens. Dois experimentos contíguos foram conduzidos em Guarapuava-PR, no delineamento em blocos ao acaso com três repetições. Foi estimada a capacidade geral (CGC) e específica (CEC) de combinação para produtividade de grãos e severidade de doenças avaliadas pela área abaixo da curva de progresso da ferrugem comum (Puccinia sorghi) (AACPF) e da cercosporiose (Cercospora zeae-maydis) (AACPC). Os efeitos da CGC e CEC foram significativos para a produtividade de grãos e severidade das doenças em ambas as densidades de semeadura, revelando a importância tanto dos efeitos aditivos quanto não aditivos. Houve interação CGC x densidades de semeadura significativa somente para produtividade de grãos. Os cruzamentos P30F53 x AG8021 e P30F53 x Penta apresentaram CEC negativa para AACPF e AACPC na média dos experimentos. Os híbridos GNZ 2004 e P30F53 destacaram-se apresentando CGC positiva para produtividade de grãos e negativa para a AACPF e AACPC em ambos os experimentos, portanto são recomendados para a geração de populações-base para a obtenção de linhagens adaptadas tanto a densidades populacionais convencionais, quanto a plantios mais adensados, atendendo às atuais tendências de manejo da cultura do milho.(AU)


Subject(s)
Zea mays , Crosses, Genetic , 24444
18.
Semina ciênc. agrar ; 36(1): 123-134, 2015. tab
Article in Portuguese | VETINDEX | ID: biblio-1499868

ABSTRACT

Seven commercial maize hybrids (AS1575, 2B688, Penta, GNZ2004, AG8021, Sprint e P30F53) were intercrossed in a complete diallel, excluded reciprocal, obtaining 21 crosses. The 28 treatments were evaluated in two environments characterized by different densities (62,500 and 90,000 plants ha-1), with the aim of selecting the most promising parents for generating base population to obtain lines. Two experiments were carried out in Guarapuava-PR, at randomized block design with three replications. We estimated the general (GCA) and specific (SCA) combining abilities for yield and disease severity assessed by the area under the common rust (Puccinia sorghi) progress curve (AURPC) and the area under the leaf spot (Cercospora zeae-maydis) progress curve (AULPC). The effects of GCA and SCA were significant for grain yield and diseases severity in both densities, revealing the importance of both additive and non-additive effects. There GCA x densities interaction was significant only for grain yield. Crossings P30F53 x AG8021 and P30F53 x Penta had negative estimates of SCA for AURPC and AULPC on the environments average. Hybrids GNZ 2004 and P30F53 stood out showing positive GCA for grain yield and negative for AURPC and AULPC in both densities and therefore are recommended for generating base populations for obtaining lines adapted for both densities, conventional and denser plantings, given the current trends in management of maize.


Sete híbridos comerciais de milho (AS1575, 2B688, Penta, GNZ2004, AG8021, Sprint e P30F53) foram utilizados como genitores de um dialelo completo, sem os recíprocos, gerando 21 cruzamentos. Os 28 tratamentos foram avaliados em duas densidades populacionais (62.500 e 90.000 plantas ha-1), com o objetivo de selecionar os genitores mais promissores para a geração de populações-base para a obtenção de linhagens. Dois experimentos contíguos foram conduzidos em Guarapuava-PR, no delineamento em blocos ao acaso com três repetições. Foi estimada a capacidade geral (CGC) e específica (CEC) de combinação para produtividade de grãos e severidade de doenças avaliadas pela área abaixo da curva de progresso da ferrugem comum (Puccinia sorghi) (AACPF) e da cercosporiose (Cercospora zeae-maydis) (AACPC). Os efeitos da CGC e CEC foram significativos para a produtividade de grãos e severidade das doenças em ambas as densidades de semeadura, revelando a importância tanto dos efeitos aditivos quanto não aditivos. Houve interação CGC x densidades de semeadura significativa somente para produtividade de grãos. Os cruzamentos P30F53 x AG8021 e P30F53 x Penta apresentaram CEC negativa para AACPF e AACPC na média dos experimentos. Os híbridos GNZ 2004 e P30F53 destacaram-se apresentando CGC positiva para produtividade de grãos e negativa para a AACPF e AACPC em ambos os experimentos, portanto são recomendados para a geração de populações-base para a obtenção de linhagens adaptadas tanto a densidades populacionais convencionais, quanto a plantios mais adensados, atendendo às atuais tendências de manejo da cultura do milho.


Subject(s)
Crosses, Genetic , Zea mays , 24444
19.
Semina ciênc. agrar ; 36(2): 917-932, 2015. tab
Article in Portuguese | VETINDEX | ID: biblio-1499924

ABSTRACT

O experimento foi conduzido no Núcleo de Produção Animal (NUPRAN) da Universidade Estadual do Centro Oeste (UNICENTRO), com o objetivo de avaliar o efeito da colheita da planta de milho em diferentes estádios reprodutivos e com diferentes processamentos de grãos sobre as perdas e o valor nutritivo das silagens. Diferenças (P 0,05) foram evidenciadas para o quesito estádio reprodutivo, quanto aos teores de matéria seca (26,70% contra 34,78%), matéria mineral (4,35% contra 3,87%), fibra em detergente ácido (32,63% contra 23,36%) e fibra em detergente neutro (52,06% contra 42,07%), respectivamente para os estádios grão pastoso (R3) e grão duro (R5). Elevadas perdas de matéria seca foram encontradas no estádio R3, sendo estas nas dimensões de 14,59% e 20,06%, respectivamente para as silagens com e sem processador de grãos. Quanto ao parâmetro de perdas de proteína bruta, não foram evidenciadas diferenças significativas para os efeitos isolados ou associados dos estádios de colheita e processamento do grão na silagem de milho. Elevadas diferenças podem ser percebidas quanto às perdas de fibra em detergente neutro e perdas de fibra em detergente ácido das silagens, justificado pelo aumento nos teores de fibra em detergente ácido na proporção média de 22,96% nas silagens colhidas no estádio R3 e redução nos seus teores com média de 4,60%, para o estádio R5. Não observou-se...


The aim of this study was evaluate the harvest of corn plant in different reproductive stages and different processing grain about losses and nutritive value of silages. Significant differences in the stage of harvest showed up in lower (P 0.05) for dry matter (26.70% against 34.78%) and higher values for contents of mineral matter (4.35 % against 3.87%), acid detergent fiber (32.63% vs. 23.36%) and neutral detergent fiber (52.06% against 42.07%) in the level of harvest dough (R3 ) compared to the level of hard grain (R5), respectively. High dry matter losses were found at stage R3, which are the dimensions of 14.59% and 20.06% respectively to silages with and without grain processor, significantly different (P> 0.05) results found for the R5 stage, which had an average loss of around 5.77%, demonstrating that silage harvested at R5 stage, allow greater dry matter recovery and hence greater savings for the farmer. Regarding the parameter of losses of crude protein, there were no significant differences for the effects of isolated or associated stages of harvesting and processing of grain in corn silage. Large differences can be perceived as the loss of neutral detergent fiber and loss of acid detergent fiber silage, justified by the increase in the levels of acid detergent fiber in the average share of 22.96% in the silage harvested at stage R3 and reduction in their...


Subject(s)
Plant Development , Silage , Nutritive Value , Zea mays/growth & development
20.
Semina ciênc. agrar ; 36(4): 2395-2406, 2015. tab
Article in Portuguese | VETINDEX | ID: biblio-1500049

ABSTRACT

O objetivo do trabalho foi avaliar o comportamento relativo de 74 linhagens parcialmente endogâmicas (S4) provenientes do cruzamento entre os híbridos comerciais P30P70 e Dow8460 em topcrosses com o híbrido simples comercial P30F53 (testador), mais as testemunhas (híbridos Dow8460, P30F53 e Status). A produtividade de grãos (PG) foi avaliada em dois ambientes em Guarapuava-PR. Houve efeito significativo de genótipos, ambientes e da interação genótipos x ambientes quanto à produtividade de grãos (PG). Entre os híbridos topcrosses (HTC) a PG variou de 8.302 (HTC 123, no ambiente 2) a 14.809 kg ha-1 (HTC 11, no ambiente 1). No ambiente 1 foram avaliadas características agronômicas da forragem e bromatológicas da silagem. A produtividade de massa verde (PMV) da forragem variou de 49.857 (HTC 208) a 80.642 kg ha-1 (HTC 22) e a produtividade de massa seca (PMS) variou de 11.072 (HTC 217) a 24.143 kg ha-1 (HTC 22). Os teores de fibra em detergente neutro (FDN) variaram de 45,39 (HTC 80) a 56,71% (HTC 77) e os teores de fibra em detergente ácido (FDA) variaram de 25,45 (HTC 80) a 35,60% (HTC 99). Para o valor relativo da silagem (VRS) foram obtidos índices médios variando de 103 (HTC 148) à 142 (HTC 80). Para todos os caracteres houve topcrosses que não diferiram das melhores testemunhas. Os HTC 22 e 53 foram superiores considerando todo o conjunto de caracteres forrageiros e...


The objective of this study was to evaluate the relative performance of 74 partially inbred lines (S4) from crosses between the commercial hybrids P30P70 and Dow8460 in topcrosses with the commercial single cross hybrid P30F53 (tester), and checks (hybrids Dow8460, P30F53 and Status). The grain yield (GY) was evaluated in two environments in Guarapuava-PR. The effects of genotypes, environments and genotypes x environments interaction were significant for grain yield (GY). Among the topcrosses hybrids (TCH) the GY ranged from 8,302 (TCH 123, in the environment 2) to 14,809 kg ha-1 (TCH 11, in the environment 1). In the environment 1 we evaluated agronomic characteristics of the forage and bromatologic characteristics of the silage. The green mass productivity (GMP) of forage ranged from 49,857 (TCH 208) to 80,642 kg ha-1 (TCH 22) and the dry mass productivity (DMP) ranged from 11,072 (TCH 217) to 24,143 kg ha-1 (TCH 22). The contents of neutral detergent fiber (NDF) ranged from 45.39 (TCH 80) to 56.71% (TCH 77) and the contents of acid detergent fiber (ADF) ranged from 25.45 (TCH 80) to 35 60% (TCH 99). The relative value of the silage (RVS) presented average ratios ranged from 103 (TCH 148) to 142 (TCH 80). For all the characteristics many topcrosses did not differ from the best checks. TCH 22 and 53 were higher considering the set of all characteristics of forage and silage...


Subject(s)
Hybridization, Genetic , Plant Breeding , Zea mays/growth & development , Zea mays/genetics
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