Wener Santos de Almeida

Correlation and path analysis in components of grain yield of cowpea genotypes

This study aimed at verifying the effect of genotype x environment interaction on the relative contribution of yield components and final production of different cowpea genotypes. For this, data of yield components of 22 cowpea genotypes were evaluated in four environments in the State of Ceara. A one-way ANOVA tested the variability between genotypes and the Scott-Knott test compared the mean values of the genotypes. The correlations were estimated by a path analysis. A differentiated response from the genotypes to each environment was observed for all traits examined, indicating the need to perform the test for each situation separately. The number of pods per plant is the yield component with great potential of genetic gain in additional cycles of selection of more productive genotypes. The number of pods per plant and the number of grains per pod were the yield components with greater direct effects on the productivity.

Identificação de genótipos de feijão-caupi tolerantes a salinidade avaliado por meio de método multivariado

The objective of this research was to identify genotypes tolerant to stress caused by NaCl and the mixture of NaCl, CaCl2 and MgCl2 in irrigation water in the early stages of development. The levels of electrical conductivity of saturation extract were 0, 0.25, 5.0 and 7.5dS m-1. The tolerance of cowpea was evaluated by the relative reduction in shoot dry matter of each genotype. The genotype CE-182 had more tolerant levels of 2.5, 5.0 and 7.5dS m-1 in saline water with NaCl. In the solution mixture of salts, the genotypes and CE-9 and CE-551 were the most tolerant. According to the results obtained by clustering using the UPGMA method it can verified that the most promising combinations for crosses which obtained superior progenies in the development of cultivars tolerant to salinity were found between genotypes CE-182 and CE-250 and between CE-551 and CE-9.

The use of different clustering methods in the evaluation of genetic diversity in upland cotton

A geracao e avaliacao continua de novos genotipos, por meio do melhoramento genetico, e fundamental para a obtencao de novas cultivares. Foi o objetivo deste trabalho avaliar a divergencia genetica entre cultivares de algodoeiro herbaceo (Gossypium hirsutum L.), por meio de caracteristicas agronomicas e tecnologicas da fibra, visando a selecao de parentais superiores. O experimento foi implantado na Universidade Federal do Ceara, Fortaleza/CE, em 2010. Foram usadas 11 cultivares de algodao herbaceo, utilizando o delineamento experimental em blocos casualizados, com tres repeticoes. Para avaliacao da divergencia genetica entre as cultivares foi obtida a matriz de distâncias generalizada de Mahalanobis, e em seguida, realizado agrupamento por diferentes metodos, sendo eles o metodo da ligacao simples, de Ward, da ligacao completa, da mediana, da ligacao media dentro de grupo e da ligacao media entre grupo. Ha variabilidade genetica entre os genotipos avaliados. O metodo de agrupamento que apresentou maior consistencia foi a ligacao media entre grupo. O peso medio do capulho apresentou a maior contribuicao para a diversidade genetica, seguida do alongamento a ruptura dentre os caracteres avaliados. As cultivares de maior divergencia genetica, usando o metodo de ligacao media entre grupo, foram a BRS Acacia e LD Frego; as de maior similaridade foram a BRS Itauba e BRS Araripe.

Correlations and path analysis in components of fiber yield in cultivars of upland cotton

This study evaluated the relative contribution of agronomic and technological components on the fiber yield in upland cotton cultivars. The experiment was carried out with 11 upland cotton cultivars in a completely randomized blocks design with three replications. Initially, we performed analysis of variance, with the F test at 5% probability for the effect of cultivar as fixed ef - fects as well as block and environment effects as random. Then the values were ordered according to cluster test Scott-Knott, at 5% probability level. The significance of the null hypothesis that all possible canonical correlations are null was evaluated using the chi-square test. The correlations were estimated through the path analysis. By examining the canonical correla- tions there was dependence between the two groups of variables and therefore it is possible to promote changes in certain characteristics through the selection of others correlated. Plants of upland cotton with higher fiber yield were influenced by the decrease in average weight of the cotton boll. When there is a reduced fiber yield, there is also an increase in uniformity and strength thereof. The fiber resistance had negative indirect effects on the fiber uniformity and length.