Heterosis and combining ability over environments in okra (Abelmoschus esculentus (L.) Moench).
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Date
2004
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Abstract
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.
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Keywords
Okra, Heterosis, combining ability