Gene Action of Cassava Resistance Metabolites to Whitefly (Bemisia tabaci)

Several metabolites are linked to cassava resistance to whitefly. There is limited information however, on the mode of gene action of the metabolites associated with cassava resistance to whitefly (Bemisia tabaci). The objective of the study was to determine the combining abilities and mode of gene action of salicylic acid, antioxidative capacity, total phenolic content, flavonoid, tannin, peroxidase and protein of selected cassava genotypes. Ten genotypes were crossed in half diallel and the parental and 45 S1 progenies evaluated for nymph count, whitefly count, leaf damage and sooty mold at Namulonge in season two of 2016. In season one and two of 2017, the parental genotypes and their corresponding forty-five S1 progenies were evaluated in randomized complete blocks with two replications for Bemisia tabaci population and leaf damage and leaf metabolite content assayed. The results indicated highly significant (P<.001) differences among genotypes for general combining ability (GCA) to antioxidative capacity; (P<.05) for total phenolic content, peroxidase and protein and (P<.01) for salicylic acid, tannin and flavonoid. The specific combining ability (SCA)showed significant (P<.001) differences for salicylic acid; (P<.01) for antioxidative capacity and total phenolic content. The additive variance was significant (P< .05) for flavonoid, protein; (P<.01) for antioxidative capacity, total phenolic content, tannin and peroxidase. The dominance variance had high significance (P<.001) for salicylic acid; (P<.05) for flavonoid and (P<.01) for antioxidative capacity and total phenolic content. Although additive gene action was higher than non-additive, both were influencing most metabolites indicating complexity of inheritance. A critical evaluation is necessary when exploiting metabolite related traits in breeding for resistance to Bemisia tabaci.

Desempenho de codornas de corte em cruzamentos dialélicos / Performance of meat type quails in diallel cross

Objetivou-se com este trabalho avaliar o desempenho de quatro linhagens (L1, L2, L3 e L4) de codornas de corte em cruzamentos dialélicos. O presente estudo foi realizado nas instalações do Programa de Melhoramento de Codornas do Departamento de Zootecnia da UFVJM, no período de 16 de dezembro de 2011 a 26 de janeiro de 2012. Foram avaliados o peso corporal médio ao nascimento, aos 35 e aos 42 dias de idade; o consumo médio de dieta e a conversão alimentar do nascimento aos 35 dias e do nascimento aos 42 dias de idade. As análises dialélicas foram desenvolvidas de forma univariada, considerando-se a metodologia de dialelos completos, a partir das médias das combinações genotípicas resultantes de um experimento inteiramente ao acaso com três repetições. A capacidade geral de combinação foi significativa para todas as características avaliadas, com exceção do consumo médio de dieta e da conversão alimentar do nascimento aos 35 dias de idade. Houve efeito significativo da capacidade específica de combinação sobre o peso corporal ao nascimento (L2xL3; L2xL4; L1xL4); conversão alimentar do nascimento aos 35 dias (L1xL3; L2xL4) e do nascimento aos 42 dias (L1xL3; L2xL3; L2xL4); consumo médio de dieta do nascimento aos 35 dias de idade (L1xL3; L2xL3), o que permitiu a identificação de combinações híbridas mais favoráveis. O efeito recíproco foi significativo apenas sobre o peso ao nascimento. Com base na capacidade geral de combinação, as linhagens mais favoráveis para peso corporal foram a L1 e a L2. Para a conversão alimentar, pela capacidade específica de combinação, os cruzamentos L1xL3 e L2xL4 apresentaram o melhor resultado, enquanto para o consumo de dieta do nascimento aos 35 dias de idade, os cruzamentos L1xL3 e L2xL3 são os mais indicados.

The aim of this study was to evaluate the performance of four strains of meat type quails, designated L1, L2, L3 and L4 in diallel crosses. This study was carried out at the premises of the Genetic Improvement Program for Quails of UFVJM, from December 2011 to May 2012. The average body weight at hatch, at 35 and at 42 days old, the average daily feed intake at 35 and at 42 days old, and feed conversion at 35 and 42 days old were evaluated. Diallel analyzes were developed using univariate analyses, considering the methodology of complete diallel, from the average of the genotype combinations resulting in a complete randomized design with three replications. The combining ability analysis revealed significance for general combining ability for all traits, except for average feed intake and feed conversion at 35 days old. There was significant effect of specific combining ability for hatch weight (L2xL3; L2xL4; L1xL4); feed conversion from hatch to 35 days of age (L1xL3; L2xL4), and from hatch to 42 days (L1xL3; L2xL3; L2xL4); and average feed intake from hatch to 35 days of age (L1xL3; L2xL3), thus allowing the identification of more favorable hybrid combinations. The reciprocal effect showed significance only for hatch weight. Based on general combining ability, the strains which are more favorable for increased body weight were L1 and L2. For feed conversion, for the specific combining ability, the crosses L1xL3 and L2xL4 showed the best results, while for feed intake from hatch to 35 days old, the crosses L1xL3 and L2xL3 would be the most suitable.

Rendimento de carcaça de codornas de corte em cruzamentos dialélicos / Carcass yield of meat quails in diallel cross

Objetivou-se com este trabalho avaliar o peso e rendimento de carcaça e cortes de codornas por meio da metodologia de cruzamentos dialélicos. Foram utilizadas quatro linhagens de codornas de corte, denominadas L1, L2, L3 e L4. O sistema de cruzamento proporcionou 16 grupos de progênies, sendo quatro parentais (puros), seis mestiços F1 e seis mestiços F1 recíprocos, alojadas em bateria experimental em três repetições. Aos 42 dias de idade, cinco machos de cada unidade experimental foram escolhidos ao acaso e destinados ao abate, para avaliação do peso aos 42 dias de idade, peso e rendimento de carcaça, do peito, das pernas e das asas. A análise dialélica foi desenvolvida de forma univariada, considerando-se a metodologia de dialelos completos, incluindo as p² combinações das linhagens, a partir das médias das combinações genotípicas. As análises de capacidade combinatória mostraram significância para capacidade geral de combinação (CGC) para peso corporal, da carcaça, peito, pernas e asas, enquanto a capacidade específica de combinação (CEC) foi significativa apenas para o peso e rendimento de pernas. Os quadrados médios da CGG apresentaram, de forma geral, valores maiores que da CEC, revelando a predominância de efeitos aditivos na expressão dessas características, o que indica que melhorias nestas características podem ser conseguidas por meio de processos de seleção intrapopulacional. As linhas L1, L2 e L4 apresentaram valores positivos para CGC em praticamente todas as características avaliadas, e podem ser consideradas superiores à média das linhagens envolvidas no dialelo, sendo, portanto, favoráveis para proporcionarem aumento nas características avaliadas. Foi observado maior efeito dos genes aditivos, indicando que a seleção das linhas puras pode trazer ganhos satisfatórios, sendo a linha L2 a mais promissora, com base em sua capacidade geral de combinação. Para peso de pernas, o cruzamento L2xL4 seria o mais indicado e, para o rendimento de pernas, o cruzamento L1xL4, com base na capacidade específica de combinação.

This study aimed to evaluate the weight and carcass yield and cuts of meat quails through the methodology of diallel crosses. It was used four strains of meat quails, named L1, L2, L3 and L4. The mating system provided 16 groups of progenies, four parents (pure), six F1 crossbred and six F1 reciprocal crossbred, allocated in experimental batteries in three replicates. On the day 42th day of life, five males from each experimental unit were randomly chosen and destined for slaughter, to evaluate weight, weight and production of carcass, chest and legs; and wings yield. The diallel analyses were developed using univariate analysis, considering the methodology of complete diallel, including p² combinations, from the average of the genotype combinations. The analyses of combining ability showed significance for general combining ability (GCA), body weight, carcass weight, breast meat, legs and wings, while specific combining ability (SCA) was significant only for the weight and leg yield. The mean squares of GCA were, in general, higher values than SCA ones, showing the prevalence of additive effects on expression of these traits, indicating that these improved traits can be achieved through the selection process. The lines L1, L2 and L4 showed positive GCA values in almost all traits evaluated, and can be considered above the average of the lines involved in diallel; therefore, provide the most favorable for increasing the assessed traits. It was observed a greater additive effect of genes, suggesting that the selection of inbred lines can bring satisfactory gains, being the line L2 the most promising, based on their general combining ability. For legs' weight crossing L2xL4 would be more appropriate, and for legs yield, crossing L1xL4, based on specific combining ability.

Capacidade combinatória de cultivares de soja em f2, sob condições de cerrado tocantinense / Combining ability of soybean cultivars in f2, under conditions of cerrado tocantinense

A possibilidade de predição dos ganhos obtidos por uma seleção constitui-se em uma das principais contribuições da genética quantitativa e, por conseguinte, no processo de melhoramento. Diante do exposto o objetivo do trabalho foi avaliar 21 tratamentos (06 parentais e 15 combinações dialélicas em F2), sob condições de campo em Gurupi- TO, no ano 2010/11, quanto à capacidade geral (CGC) e específica de combinação (CEC), em um esquema de dialelo completo, sem os recíprocos. A metodologia utilizada foi proposta por Griffing (1956). O delineamento experimental utilizado foi inteiramente casualizado, constituído por 21 tratamentos em 04 repetições. As características estudadas foram: o número de vagens por planta, número de grãos por planta e produção de grãos por planta (gramas/planta). Para todas as características foi detectado efeito significativo para CGC e CEC. O genitor M 9056RR foi o mais promissor e a combinação M 9056RR x P98Y70 a mais indicada para formação de uma população segregante com características superiores.

The ability to predict the gains made by a selection is in one of the main contributions of quantitative genetics and therefore in the process of improvement. In this light the objective of this study was to evaluate 21 treatments (06 parental and 15 diallel combinations in F2), under field conditions in Gurupi-TO in the year 2010/11, regarding the general ability (GCA) and specific combining (SCA ) in a complete diallel scheme without reciprocals. The methodology was proposed by Griffing (1956). The experimental design was randomized, consisting of 21 treatments in 04 replications. The characteristics studied were: number of pods per plant, number of grains per plant and yield per plant (grams / plant). For all features significant effects for GCA and SCA. The parent M 9056RR was the most promising and the combination M 9056RR x P98Y70 optimal for formation of a segregating population with superior features.

General and specific combining ability estimates of physiological traits for moisture stress tolerance in groundnut (arachis hypogaea l.).

The combining abilities for physiological traits in peanut were examined to understand the type of gene action governing these traits, and to identify peanut genotypes suitable for use as parents in breeding for improvement in physiological traits. Substantial genetic variability was observed among the hybrids for the traits studied. The genotypes, TPT-4 and ICGV-91114 were found to be good combiners for developing early flowering types, while ICGV-91114, TCGS- 584, TPT-4 and JL-220 were good combiners for developing early maturing. For SPAD chlorophyll meter reading was K-1375 was best general combiner. Among the parents K-1375, TIR-25 and TCGS-647 were found to be superior as evident from its highest significant positive general combining ability effects for specific leaf area. The best good combiner for transpiration rate was ICGV-91114 and for photosynthetic rate was TIR-25. For water use efficiency only the genotype, TPT-4 was the best combiner. Best performing parents for harvest index were JL-220 and TPT-4. The hybrid, TPT-4 x TIR-25 was the specific hybrid for high water use efficiency. For SPAD chlorophyll meter reading only one cross, K-1375 x TCGS647 was considered to be the good performing hybrid. Two hybrids viz., TIR-25 x TCGS- 647 and ICGV-91114 x JL-220 were found to be good specific combiners for harvest index. A perusal of results of combining ability analysis indicated considerable non-additive gene action in the inheritance of majority of the attributes studied. The non-fixable dominance deviation and epistatic effects are likely to hinder improvement through simple pedigree selection, which is commonly followed in groundnut. Alternatively intermating of the F2 segregants followed by recurrent selection and pedigree breeding can harness the different kinds of gene - effects. Repeated selection and inter-mating of segregating materials for two or three cycles, makes it possible to achieve simultaneously improvement in physiological attributes.

Partial diallel analysis of agronomic characters in rice (Oryza sativa L.)

Rice (Oryza sativa L.) breeding seeking to combine high productivity and cold tolerance for the temperate Latin America region is an important challenge. We estimated some useful parameters which can be used to investigate the genetic control of agronomic characters in crosses combining cold tolerance and productivity. A partial diallel design was used in crosses between six tropical indica rice cold susceptible genotypes (group 1) and seven japonica or indica/japonica cold tolerant rice genotypes (group 2). Parents and crosses were evaluated for agronomic characters under field conditions in two different experiments in 2005. The results showed significant mid-parent heterosis for all characters (plant height, tiller number, days to 50 percent flowering, panicle length, grains per panicle, sterility, and one-hundred grain weight). The predominant direction of dominance effects was negative for days to 50 percent flowering, and positive for all the other characters. General combining ability (GCA) and specific combining ability (SCA) were significant for all characters, although the GCA effects of the two groups were more important than the SCA effects.