Gains from selection for oil content in cotton

Abstract

With the growing demand for biodiesel, there is greater interest in increasing the oil content of cotton cultivars; this has made cotton breeding programs incorporate this trait in selections. Screening studies on the germplasm bank of “Embrapa Algodão” have shown variability for this trait. This study aimed to select cotton segregating genotypes in the F5 generation by estimating genetic and phenotypic parameters, such as heritability, and gains from direct and indirect selection. Thus, we selected three accessions with high oil content, which are, BRS Aroeira, Acala 1.13-3-1 e 149 FURRS, which were crossed with inbred lines more productive fiber of the breeding program of “Embrapa Algodão”, making a total of nine types of crosses. The generations were defined by pedigree method, always using selection between and within progenies for higher oil content. The analyzes were determined from F3 seeds, which were conducted until the F5 generation with line 22, these evaluated in a completely randomized trial with 4 replications; for each replication, three oil content analysis were made. For the analysis of variance, it was used the mean of these three valuation. The estimated data of the oil content of the studied generations enables the estimation of: phenotypic, genotypic and environmental variance; heritability through parent–progeny regression, being F3 (parent) and F5 (progeny); and the achievement of genetic gain. It was determined that there was genetic variation among genotypes, indicating the possibility of obtaining gains through between and within selection of progenies, and that F5 generation is more appropriate to maximize genetic gain from selection for seed oil content in cotton. The estimated genetic gain in F5 generation corresponded to 4.98%, which is higher than in F3 generation, denoting that selection for the character is far more efficient when performing direct selection in F5. CNPA 2011/12 line presents the potential to be used as a parent in breeding programs which aim at improving the oil content of cotton.