Correlações genotípicas, fenotípicas e ambientais entre caracteres de mamoneira

Abstract

Um dos grandes desafios atuais da pesquisa agrícola é a produção de cultivares melhoradas de mamoneira, com estabilidade genética, alta qualidade e potencial produtivo. Objetivou-se, no presente trabalho, estimar as correlações genotípica, fenotípica e de ambiente entre caracteres de mamona para facilitar a caracterização dos acessos. Foram avaliados em Lavras, MG, no delineamento de blocos casualizados com três repetições, quinze acessos de mamona. Os caracteres avaliados foram altura da planta, altura do caule, número de internódios, diâmetro do caule, número de cachos, estande final e peso de 100 sementes. Observou-se que houve correlação fenotípica positiva do número de internódios e altura do caule, altura do caule e altura da planta, altura da planta e diâmetro do caule e por fim entre diâmetro do caule e peso de 100 sementes. Houve também correlação ambiental positiva entre as correlações altura de caule e altura de planta, altura de planta e diâmetro do caule, altura da planta e estande final e diâmetro do caule e número de cachos, concluindo que as correlações estimadas possibilitaram conhecer as associações entre os caracteres, fornecendo importantes informações para o estabelecimento de um plano de melhoramento genético da mamona, a partir dos acessos avaliados.

Germination and Initial Growth of Cowpea Cultivars Under Osmotic Stress and Salicylic Acid

“…Thus, when there is significant correlation between both features, it is possible to estimate increase in one of them through the indirect selection of the other. Such estimated correlations allow researchers to determine the associations between structures of plants, which provide the basis for the establishment of a genetic improvement plan under conditions of water limitation in soil (RODRIGUES et al, 2010). Figure 2.…”

Comparison of methods for selection of castor beans lineages

“…It can be observed that only the groups with higher and lower productivity, were formed by the same lineages by any hierarchical agglomerative method used, presenting the longest distance from Mahalanobis (Table 4), which is interesting for the indication of possible crosses between genetically divergent progenitors, leading to the production of hybrid hybrids, however, the lineages with yield of grains between 1400 and 1900, were allocated in different groups depending on the method used, which is not interesting, because it can lead to mistaken decision making (Machado et al, 2013;Rodrigues et al, 2010). The "Euclidean Distance", "Ward Linkage" method, presented a smaller distance between groups 2 and 4, proving that these groups present greater similarity and greater distance between 2 and 3, showing the lowest similarity, which may represent a better result when the selection is in function to a single variable, for example grain yield (Cargnelutti Filho & Guadagnin.…”

Genetic parameters in agronomic characters for selection of superior lineages of Ricinus communis L

“…Knowledge on the correlations between agronomic traits is important for genetic improvement studies, since they guide the selection of superior lineages, especially when the characters are favorably correlated, which makes it possible to obtain gains for one character indirectly by selection of an associated character. This is advantageous, especially when a character of high economic value has low heritability or is difficult to evaluate compared with another associated character (CRUZ et al, 1997;RODRIGUES et al, 2010). However, if a character is positively correlated with other characters and negatively correlated with others, it is important to take care to avoid selecting for a character that may cause some undesirable change.…”

“…Knowledge on the magnitude and direction of genotype correlations between characters is extremely important for the breeder to formulate simultaneous selection strategies in multiple characters. This is advantageous, especially when a character of high economic value has low heritability, or is difficult to evaluate compared to another associated character (RODRIGUES et al, 2010;RODRÍGUEZ et al, 1998). There were significant correlations between vegetative cycle and all characters, which were positive with the PHE and negative with the other characters.…”