ABSTRACT This study aimed to characterize and select silk blossom genotypes (Calotropis procera) with forage potential. Between April and July 2014, we cultivated 89 genotypes in plastic tubes arranged in a randomized block design with three replications; each experimental plot was composed of 8 plants. The following characteristics were evaluated: plant height (PH), stem diameter (SD), number of leaves (NL), total leaf area (TLA), leaf fresh mass (LFM), stem fresh mass (SFM), root fresh mass (RFM), leaf dry mass (LDM), stem dry mass (SDM), and root dry mass (RDM). Significant differences (p < 0.05) among genotypes were observed for all characteristics, except for NL at 45 and 60 days after sowing (DAS) and for RFM at 60 DAS. Broad-sense heritability estimates and genotype means had medium and high values for most characteristics. Genetic variability among C. procera genotypes was observed. High gain selection was found for the characteristics TLA, PH, SFM, LFM, SDM, and LDM as the genotypes 79, 65, 48, 12, 51, 35, 63, 25, 1, and 46 are suitable for future breeding works to improve forage production. | RESUMO Objetivou-se caracterizar e selecionar genótipos de flor-de-seda (Calotropis procera) com potencial para forragicultura. Para tanto, 89 genótipos foram cultivados em tubetes organizados em blocos ao acaso com três repetições, no período entre abril e julho de 2014, sendo a parcela experimental composta por 8 plantas. Foram avaliadas as características: altura da planta (AP), diâmetro caulinar (DC), número de folhas (NF), área foliar total (AFT), massa verde das folhas (MVF), massa verde do caule (MVC), massa verde da raiz (MVR), massa seca das folhas (MSF), massa seca do caule (MSC) e massa seca da raiz (MSR). Houve diferença significativa (p<0,05) entre os genótipos para todos os caracteres, exceto para NF aos 45 e 60 dias após a semeadura (DAS) e MVR aos 60 DAS. As estimativas de herdabilidade no sentido amplo e de média de genótipos foram de média e alta magnitude na maioria dos caracteres. Existe variabilidade genética entre os genótipos de C. procera. Observou-se ganho elevado de seleção para AFT, AP, MVC, MVF, MSC e MSF. Os genótipos identificados como 79, 65, 48, 12, 51, 35, 63, 25, 1 e 46 são indicados para futuros trabalhos de melhoramento genético visando à produção de forragem.

ABSTRACT In the present study the objective was to evaluate the genetic diversity among families of maize siblings for resistance to foliar diseases associated with their agronomic potential, identifying groups of families that can be used as sources of resistance in maize crop. The experiments were conducted in the experimental area of the Federal University of Goiás at the Jataí Regional Unit, in Jataí, GO, Brazil, constituted by 182 half-sibling families of maize and two commercial hybrids as a control. The 182 half-sibling families were divided into three experiments with 60, 60 and 62 families, respectively. The experimental design used was randomized blocks, with three replicates. Eight quantitative characters and 4 foliar diseases were evaluated. The multivariate analysis technique was used to measure the genetic divergence for the four foliar diseases represented by the generalized Mahalanobis distance. Based on the genetic dissimilarity matrix, the dendrogram was constructed using the clustering method of the average distance between groups (Unweighted Pair Group Method with Arithmetic Mean - UPGMA). After defining the groups, univariate analysis of variance was performed in order to evaluate the effects of the groups on each character studied. Comparisons were made between the means of the groups, using the Tukey test (p <0.05). White spot (32.53%) was the disease that most contributed to the total divergence between families. Group 10 stood out among the others as a source of resistance to the disease complex associated with yield. The genetic variability of families for foliar disease complex reveals potential for future studies facing pyramiding genes. | RESUMO No presente trabalho objetivou-se avaliar a diversidade genética entre famílias de meios irmãos de milho para resistência a doenças foliares associada ao seu potencial agronômico, identificando grupos de famílias que possam ser utilizadas como fontes de resistência na cultura do milho. Os experimentos foram conduzidos na área experimental da Universidade Federal de Goiás na Regional Jataí, em Jataí (GO), constituído por 182 famílias de meios-irmãos de milho e dois híbridos comerciais como testemunha. As 182 famílias de meios-irmãos foram divididas em três experimentos com 60, 60 e 62 famílias, respectivamente. O delineamento experimental utilizado foi de blocos casualizados, com três repetições. Foram avaliados oito caracteres quantitativos e quatro doenças foliares. Foi utilizada a técnica de análise multivariada para medir a divergência genética para as quatro doenças foliares representada pela distância generalizada de Mahalanobis. Com base na matriz de dissimilaridade genética foi construído o dendrograma pelo método de agrupamento da distância média entre grupos (UPGMA). Após a definição dos grupos, realizou-se a análise de variância univariada, a fim de avaliar os efeitos dos grupos sobre cada caráter estudado. Foram realizadas comparações entre as médias dos grupos, utilizando-se do teste de Tukey (p<0,05). A incidência de mancha branca (32.53%) foi a doença que mais contribuiu para a divergência total entre as famílias. O grupo 10 destacou -se dentre os demais como fonte de resistência para o complexo de doenças associado a produtividade. A variabilidade genética das famílias para o complexo de doenças foliares revela potencial para futuros estudos voltados para piramidação de genes.

ABSTRACT Morphoagronomic characterization is a basic requirement to identify a phenotypic profile of a population. The quantification of variability allows efficient selection of superior and divergent genotypes. Thus, this study aimed to estimate the variability among 490 genotypes and seven strains, from an F2 population of Ricinus communis L., in 35 morphoagronomic traits and 12 agronomic traits. For qualitative descriptors, the entropy technique was used in the percentage frequencies of each category, computing its level using the coefficient of Rényi (1961). Quantitative descriptors were subjected to analysis of variance by the F test, and Tukey test was performed at 1% probability level. Of the morphoagronomic traits used, 13 were related to plants, nine were related to inflorescence, six were related to fruits and seven were linked to seeds, in addition to 12 agronomic traits. The material was arranged in the field with families (strains of five families) interspersed with their respective parents (controls). Stem color, shape and number of racemes collected, main color, type of secondary color and hundred-seed weight have high variability in the population, with formation of 68 groups as a function of genetic similarity. The possibility of selection as to the number of racemes harvested is clear, so it is possible to identify genotypes with higher number, aiming to enhance crop yield.