CAPACIDADE GERAL E ESPECÍFICA DE COMBINAÇÃO EM ALGODOEIRO HERBÁCEO PARA QUALIDADE DE FIBRA

Abstract

The present work aims to estimate the general and specific combining abilities involving six cotton genotypes (Gossypium hirsutum L.), and their respective hybrids (F1's), resulting from diallel crosses, and thus to select the most promising genotypes to be used in breeding programs for fiber technological quality. The experiment was carried out at the Experimental Station of Embrapa - Algodão, in the municipality of Patos - PB, Brazil. The experiment design utilized was a randomized complete block design with 21 treatments and three replicates. The experimental plot consisted of two rows of 5 m in length, which represented the useful area, at a spacing of 1.0 x 0.20 m, leaving 50 plants per plot after thinning. The statistical analysis was performed using the GENES software. Estimates of combinatorial capacities were performed according to Model 1, Method 2 proposed by Griffing (1956). The fiber technological characteristics measured were: fiber length (COMP, mm), resistance (RES, gf/tex) and micronaire (FIN, μg/in). There are significant differences between treatments and between combinatorial capacities (GCA and SCA). The effect of additive effects on the three characteristics studied was predominant. In the GCA case, the TAM B 139-17 genotype obtained the highest positive and significant estimates for COMP and RES and the highest negative and significant estimate for FIN. The best hybrid combinations were: FM 993 x TAM B 139-17, CNPA 04-2080 x PSC 355, TAM B 139-17 x TAMCOT-CAMD-E and FM 993 x TAMCOT-CAMD-E, being promising for obtaining superior lines for technological quality of the fiber.