Heterosis and combining ability over environments in okra (Abelmoschus esculentus (L.) Moench).

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In the present investigation, the information regarding heterosis, combining ability and stability parameters were obtained in respect of fruit yield and its components in okra. The material for the present study comprised of four females, nine males and resulting thirty-six hybrids, tested at the Instructional farm, Junagadh during early summer, late summer and kharif, 2003. The analysis of variance for parents and their hybrids for different characters revealed significant differences among the genotypes, environments and genotype x environment interactions for all the characters, indicating existence of considerable variability in the material studied and between the environments tested. Genotype x environment interactions which were significant for all the characters revealed differential response of the genotype to varying environments. This suggested the importance of testing material over a range of environments. Both additive and non-additive type of gene actions were involved in the genetic control of various characters studied. The magnitude of non-additive variance was higher than the additive variance for all the characters. The results further revealed that most of the superior combinations had involved at least one parent with high gca effect for almost all the traits. Parents D-1-87-5; NOL-101; NDO-10; JO (2000 K)-15; P. Kranti; HRB-107-4; HRB-55 and GO-2 were the good general combiners for yield per plant and fruits per plant. Among the crosses, HRB-55 x JO (2000K)-15 and GO-2 x NOL-101 had high sca effects for yield per plant and fruits per plant. On the basis of mean performance, the cross combination HRB-55 x D-1-87-5 recorded highest yield per plant following by P. Kranti x D-1-87-5 and GO-2 x D-1-87-5. However, highest heterobeltiosis was exhibited by the crosses P. Kranti x D-1-87-5; GO-2 x D-1-87-5 and GO-2 x NOL-101. Genotype x environment interaction exhibited significant differences for all the characters suggesting that genotypes interacted considerably with environments. Significance of g x e (linear) against pooled deviation for the characters under study suggested that genotypes differ for their linear regression on environmental index. Non-linear component also played an important role for these characters. Practical utility of any prediction in such cases will depend on the relative magnitude of these variants. Linear component was significantly higher for all characters. On the basis of mean ( X ), regression coefficient (bi) and deviation from regression (S2di) it was concluded that none of the parents and hybrids showed the stability for yield per plant but the parents viz., D-1-87-5, NDO-10 and JO (2000 K)-15 and hybrids GO-2 x P. Sawani showed above average stability for yield per plant.
Okra, Heterosis, combining ability