Seed yield combining ability among soybean genotypes in two locations
Ângela Celis de Almeida Lopes; Natal Antonio Vello and Fábio Pandini
The genotype x location interaction is an important parameter in soybean and can influence variance estimates and general and specific combining ability effects. This research to evaluate the general (GCA) and specific (SCA) combining abilities and their interactions with locations in a diallel cross system. These parameters can facilitate the identification of most promising bi-parental combinations. The six parents: (1) Hartwig, (2) Conquista, (3) USP 1-11, (4) USP 2-16, (5) MTBR 123.800, (6) USP 5-19 and the 15 crosses in the F2 generation were evaluated in a randomized complete block design, in two locations during the 1998/99 crop season. The two locations (ESALQ and Anhembi) are contrasting in topography and in physical and chemical soil properties. Data on seed yield were analyzed using an adaptation of Griffing’s method 2, model mixed B for complete diallel crosses in more than one environment. The following conclusions were obtained: both effects GCA and SCA were important; the location (L) effect was significant, with Anhembi being more favorable than ESALQ for expressing the genotypic performance in terms of seed yield; the effects of GCA x L and SCA x L also were significant; high SCA effects occurred in crosses between parents contrasting in terms of magnitude and sign of GCA; the largest GCA effect occurred for Conquista (in two locations), USP 1-11 (in ESALQ), and MTBR 123800 (in Anhembi); the largest SGA effects were observed in the crosses Hartwig x USP 1-11 (1 x 3) and Conquista x USP 5-19 (2 x 6), the first being more stable than the second in the two locations; the contribution of sii (specific combining ability of the parental i with itself) parameter showed to be important for the expression of heterosis, parental divergence and potential of the crosses in developing superior inbred lines.