Recurrent Interpopulation Selection in Popcorn: From Heterosis to Genetic Gains.

In view of the need to develop new popcorn cultivars and considering the uncertainties in choosing the most appropriate breeding methods to ensure consistent genetic progress, simultaneously for both popping expansion and grain yield, this study addressed the efficiency of interpopulation recurrent selection regarding genetic gains, the study of the response in genetic parameters as well as heterotic effects on the control of the main agronomic traits of popcorn. Two populations were established, Pop1 and Pop2. A total of 324 treatments were evaluated, which consisted of 200 half-sib families (100 from Pop1 and 100 from Pop2), 100 full-sib families from the two populations and 24 controls. The field experiment was arranged in a lattice design with three replications in two environments, in the north and northwest regions of the State of Rio de Janeiro, Brazil. The genotype × environment interaction was partitioned and the genetic parameters, heterosis and predicted gains were estimated by the Mulamba and Mock index, based on selection results in both environments. The genetic parameters detected variability that can be explored in successive interpopulation recurrent selection cycles. Exploring heterosis for GY, PE and yield components is a promising option to increase grain yield and quality. The Mulamba and Mock index was efficient in predicting the genetic gains in GY and PE. Interpopulation recurrent selection proved effective to provide genetic gains for traits with predominantly additive and dominance inheritance.

All Are in a Drought, but Some Stand Out: Multivariate Analysis in the Selection of Agronomic Efficient Popcorn Genotypes.

The search for productive germplasm adapted to adverse conditions is an important action to mitigate the harmful effects of climate change. The aim was to identify the yield potential of 50 popcorn inbred lines grown in field conditions, in two crop seasons (CS), and under contrasting water conditions (WC). Morphoagronomic, physiological, and root system traits were evaluated. Joint and individual analyses of variance were performed, in addition to the multivariate GT bip-lot analysis. Expressive reductions between WC were observed in 100-grain weight (100 GW), popping expansion (PE), grain yield (GY), expanded popcorn volume per ha (EPV), row number per ear (RNE), plant height (PH), relative chlorophyll content (SPAD), and nitrogen balance index (NBI). It was found that the SPAD, 100 GW, GY, PE, and grain number per ear (GNE) traits had the most significant impact on the selection of genotypes. Regardless of WC and CS, the ideal lines were L294 and L688 for PE; L691 and L480 for GY; and L291 and L292 for both traits. SPAD, 100 GW, and GNE can contribute to the indirect selection. Our work contributes to understanding the damage caused by drought and the integration of traits for the indirect selection of drought-tolerant popcorn genotypes.

Water Use Efficiency in Popcorn (Zea mays L. var. everta): Which Physiological Traits Would Be Useful for Breeding?

To ensure genetic gains in popcorn breeding programs carried out under drought conditions knowledge about the response of morphophysiological traits of plants to water stress for the selection of key traits is required. Therefore, the objective was to evaluate popcorn inbred lines with agronomically efficient (P2 and P3) and inefficient (L61 and L63) water use and two hybrids (P2xL61 and P3xL63) derived from these contrasting parents, cultivated under two water regimes (WW watered-WW; and water-stressed-WS) in a greenhouse, replicated five times, where each experimental unit consisted of one plant in a PVC tube. Irrigation was applied until stage V6 and suspended thereafter. Individual and combined analyses of variance were performed and the genotypic correlations and relative heteroses estimated. The water use efficient inbred lines were superior in root length (RL), root dry weight (RDW), and net CO2 assimilation rate (A), which were the characteristics that differentiated the studied genotypes most clearly. High heterosis estimates were observed for RL, SDW, leaf width (LW), leaf midrib length (LL), and agronomic water use efficiency (AWUE). The existence of a synergistic association between root angle and length for the characteristics A, stomatal conductance (gs), and chlorophyll concentration (SPAD index) proved most important for the identification and phenotyping of superior genotypes. Based on the study of these characteristics, the higher AWUE of the previously selected inbred lines could be explained. The results reinforced the importance of root physiological and morphological traits to explain AWUE and the possibility of advances by exploiting heterosis, given the morphophysiological superiority of hybrids in relation to parents.

Phenotyping Latin American Open-Pollinated Varieties of Popcorn for Environments with Low Water Availability.

Drought is a common abiotic stress in tropical and subtropical regions that limits the growth and development of agricultural crops, mainly impacting grain yield. Acting through plant breeding is the most viable alternative for obtaining genotypes more tolerant of environments with stress. This work aims to select popcorn genotypes for environments with drought and to identify discriminating traits for the evaluation of drought tolerance in popcorn germplasm. Fifteen Latin American populations of popcorn were evaluated in water stress (WS) and well-watered (WW) conditions. The evaluated traits were based in morpho-agronomic, physiological and radicular descriptors. Data were submitted to individual and joint ANOVA and GT Biplot analysis. Variability was detected between populations for all traits in both conditions. The drought caused a reduction of 30.61% and 3.5% in grain yield and popping expansion, respectively. Based in GT biplot analysis, 880POP was the most stable in WS and WW, being indicated as a promising population for cultivation in environments with water limitation. This study is going to allow the establishment of a collection of great importance to maize germplasm and to provide information to facilitate the process of selection in breeding programs focused on drought tolerance.

Silage quality of sorghum and Urochloa brizantha cultivars monocropped or intercropped in different planting systems / Qualidade de silagem de sorgo e cultivares de Urochloa brizantha em monocultivo e consorciado em diferentes sistemas de semeadura

Recently it has emerged a technique for silage production of intercropping systems of annual crop with forage through crop-livestock integration, aiming to reduce the deficit forage in the offseason. The study was conducted to evaluate the fermentation characteristics and nutritional value of silage of sorghum and Urochloa brizantha cultivars monocropped or intercropped in different planting systems. The experiment was a randomized block design, with three replications, in a 3x2+4 factorial arrangement, with three cultivars of Urochloa brizantha (Marandu; Xaraes and Piata) intercropped with grain sorghum in two planting systems (row and between rows) and four monocrops (Sorghum, Marandu palisadegrass, Xaraes palisadegrass and Piatã palisadegrass). The planting system of intercropping systems did not interfere with fermentation characteristics and chemical composition of silages. The same was found for Urochloa cultivars. Silages from intercropping sorghum with Urochloa brizantha cultivars had lower pH values, buffering capacity, acetic and butyric acids and higher values of lactic acid, besides showed superior quality, as for the parameters dry matter, ether extract and total digestible nutrient than silages from grasses produced in monocropping system. Therefore, silages of intercropping systems ensure fermentation and nutritional quality, providing interesting supplementary bulky options to be used in the offseason for feeding animals.

Surgiu recentemente a técnica de produção de silagem de sistemas consorciados de cultura anual e forrageira tropical, na integração lavoura-pecuária, com intuito de minimizar déficit de forragens na entressafra. Sendo assim, objetivou-se avaliar as características fermentativas e valor nutritivo da silagem de sorgo e cultivares de Urochloa brizantha em monocultivo e consorciado em diferentes sistemas de semeadura. O delineamento experimental utilizado foi o de bloco ao acaso, com três repetições, em esquema fatorial 3x2+4, sendo três cultivares de Urochloa brizantha (Marandu, Xaraés e Piatã), consorciadas com sorgo granífero em dois sistemas de semeadura (linha e entrelinha) e quatro monocultivos (Sorgo, Marandu, Xaraés e Piatã). A forma de semeadura dos sistemas consorciados não interferiu nas características fermentativas e químico-bromatológicas das silagens. O mesmo foi obtido para cultivares de Urochloa brizantha. As silagens do consórcio do sorgo com cultivares de Urochloa brizantha apresentaram menores valores de pH, capacidade tampão, N-NH3, ácido acético e butírico e maior ácido lático, além da qualidade superior, quanto aos parâmetros matéria seca, extrato etéreo e nutrientes digestíveis totais. Portanto, silagens dos sistemas consorciados garantem adequado processo fermentativo e qualidade nutricional, constituindo interessantes opções de volumosos suplementar para ser utilizado na entressafra na alimentação animal.

Silage quality of sorghum and Urochloa brizantha cultivars monocropped or intercropped in different planting systems / Qualidade de silagem de sorgo e cultivares de Urochloa brizantha em monocultivo e consorciado em diferentes sistemas de semeadura

Recently it has emerged a technique for silage production of intercropping systems of annual crop with forage through crop-livestock integration, aiming to reduce the deficit forage in the offseason. The study was conducted to evaluate the fermentation characteristics and nutritional value of silage of sorghum and Urochloa brizantha cultivars monocropped or intercropped in different planting systems. The experiment was a randomized block design, with three replications, in a 3x2+4 factorial arrangement, with three cultivars of Urochloa brizantha (Marandu; Xaraes and Piata) intercropped with grain sorghum in two planting systems (row and between rows) and four monocrops (Sorghum, Marandu palisadegrass, Xaraes palisadegrass and Piatã palisadegrass). The planting system of intercropping systems did not interfere with fermentation characteristics and chemical composition of silages. The same was found for Urochloa cultivars. Silages from intercropping sorghum with Urochloa brizantha cultivars had lower pH values, buffering capacity, acetic and butyric acids and higher values of lactic acid, besides showed superior quality, as for the parameters dry matter, ether extract and total digestible nutrient than silages from grasses produced in monocropping system. Therefore, silages of intercropping systems ensure fermentation and nutritional quality, providing interesting supplementary bulky options to be used in the offseason for feeding animals.(AU)

Surgiu recentemente a técnica de produção de silagem de sistemas consorciados de cultura anual e forrageira tropical, na integração lavoura-pecuária, com intuito de minimizar déficit de forragens na entressafra. Sendo assim, objetivou-se avaliar as características fermentativas e valor nutritivo da silagem de sorgo e cultivares de Urochloa brizantha em monocultivo e consorciado em diferentes sistemas de semeadura. O delineamento experimental utilizado foi o de bloco ao acaso, com três repetições, em esquema fatorial 3x2+4, sendo três cultivares de Urochloa brizantha (Marandu, Xaraés e Piatã), consorciadas com sorgo granífero em dois sistemas de semeadura (linha e entrelinha) e quatro monocultivos (Sorgo, Marandu, Xaraés e Piatã). A forma de semeadura dos sistemas consorciados não interferiu nas características fermentativas e químico-bromatológicas das silagens. O mesmo foi obtido para cultivares de Urochloa brizantha. As silagens do consórcio do sorgo com cultivares de Urochloa brizantha apresentaram menores valores de pH, capacidade tampão, N-NH3, ácido acético e butírico e maior ácido lático, além da qualidade superior, quanto aos parâmetros matéria seca, extrato etéreo e nutrientes digestíveis totais. Portanto, silagens dos sistemas consorciados garantem adequado processo fermentativo e qualidade nutricional, constituindo interessantes opções de volumosos suplementar para ser utilizado na entressafra na alimentação animal.(AU)

Protein and carbohydrate fractionation of Piata palisadegrass ensiled with energetic meals / Fracionamento de proteínas e carboidrato do capim-piatã ensilado com farelos energéticos

This study determined the fractionation of protein and carbohydrate of Piata palisadegrass ensiled with energetic meals. The experiment was developed at the Federal Institute of Goiás State, Rio Verde Campus, using a completely randomized design with four replications, in a 4 x 5 factorial arrangement, being four energetic meals (millet, corn, sorghum and wheat) and five levels of addition (0, 8, 16, 24 and 32%). The meals were obtained by grinding the grains, where the levels of addition were calculated based on natural material. The results indicated that the energetic meals represented good sources of additives for ensiling Piata palisadegrass, for considerably improving protein and carbohydrate fractions. However, among the meals used, the sorghum was less efficient by presenting a lower protein fraction (A) and higher fraction C, compared with other additives. The meals of wheat and sorghum showed higher contents of carbohydrate fractions (A+B1 and C). It is recommended the level of addition of 24% of meals, for providing better nutritional value to silage.

Desenvolveu-se esse estudo com objetivo de determinar o fracionamento de proteínas e carboidratos do capim-piatã ensilado com farelos energéticos. O experimento foi conduzido no Instituto Federal Goiano, Campus Rio Verde. O delineamento experimental utilizado foi inteiramente casualizado, com quatro repetições, em esquema fatorial 4 x 5, sendo quatro farelos energéticos (milheto, milho, sorgo e trigo) e cinco níveis de adição (0, 8, 16, 24 e 32%). Os farelos utilizados foram obtidos através da moagem dos grãos, onde a adição dos níveis foi calculada com base na matéria natural do capim-piatã. Os resultados demonstraram que os farelos energéticos, apresentam boas fontes de aditivos para a ensilagem, por trazer melhorias consideráveis nas frações proteínas e fração carboidratos. No entanto, dentre os farelos utilizados o de sorgo mostrou menos eficiente por apresentar menor fração protéica (A) e maior fração C, quando comparados com os outros aditivos. E os farelos de trigo e sorgo apresentaram maiores frações carboidratos(A+B1 e C). Recomenda-se a adição do nível de 24% dos farelos, por proporcionar melhor valor nutritivo da silagem.

Protein and carbohydrate fractionation of Piata palisadegrass ensiled with energetic meals / Fracionamento de proteínas e carboidrato do capim-piatã ensilado com farelos energéticos

This study determined the fractionation of protein and carbohydrate of Piata palisadegrass ensiled with energetic meals. The experiment was developed at the Federal Institute of Goiás State, Rio Verde Campus, using a completely randomized design with four replications, in a 4 x 5 factorial arrangement, being four energetic meals (millet, corn, sorghum and wheat) and five levels of addition (0, 8, 16, 24 and 32%). The meals were obtained by grinding the grains, where the levels of addition were calculated based on natural material. The results indicated that the energetic meals represented good sources of additives for ensiling Piata palisadegrass, for considerably improving protein and carbohydrate fractions. However, among the meals used, the sorghum was less efficient by presenting a lower protein fraction (A) and higher fraction C, compared with other additives. The meals of wheat and sorghum showed higher contents of carbohydrate fractions (A+B1 and C). It is recommended the level of addition of 24% of meals, for providing better nutritional value to silage.(AU)

Desenvolveu-se esse estudo com objetivo de determinar o fracionamento de proteínas e carboidratos do capim-piatã ensilado com farelos energéticos. O experimento foi conduzido no Instituto Federal Goiano, Campus Rio Verde. O delineamento experimental utilizado foi inteiramente casualizado, com quatro repetições, em esquema fatorial 4 x 5, sendo quatro farelos energéticos (milheto, milho, sorgo e trigo) e cinco níveis de adição (0, 8, 16, 24 e 32%). Os farelos utilizados foram obtidos através da moagem dos grãos, onde a adição dos níveis foi calculada com base na matéria natural do capim-piatã. Os resultados demonstraram que os farelos energéticos, apresentam boas fontes de aditivos para a ensilagem, por trazer melhorias consideráveis nas frações proteínas e fração carboidratos. No entanto, dentre os farelos utilizados o de sorgo mostrou menos eficiente por apresentar menor fração protéica (A) e maior fração C, quando comparados com os outros aditivos. E os farelos de trigo e sorgo apresentaram maiores frações carboidratos(A+B1 e C). Recomenda-se a adição do nível de 24% dos farelos, por proporcionar melhor valor nutritivo da silagem.(AU)

Protein and carbohydrate fractionation of Piata palisadegrass ensiled with energetic meals

This study determined the fractionation of protein and carbohydrate of Piata palisadegrass ensiled with energetic meals. The experiment was developed at the Federal Institute of Goiás State, Rio Verde Campus, using a completely randomized design with four replications, in a 4 x 5 factorial arrangement, being four energetic meals (millet, corn, sorghum and wheat) and five levels of addition (0, 8, 16, 24 and 32%). The meals were obtained by grinding the grains, where the levels of addition were calculated based on natural material. The results indicated that the energetic meals represented good sources of additives for ensiling Piata palisadegrass, for considerably improving protein and carbohydrate fractions. However, among the meals used, the sorghum was less efficient by presenting a lower protein fraction (A) and higher fraction C, compared with other additives. The meals of wheat and sorghum showed higher contents of carbohydrate fractions (A+B1 and C). It is recommended the level of addition of 24% of meals, for providing better nutritional value to silage.