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GENE EFFECTS, HETEROSIS AND INBREEDING DEPRESSION STUDIES THROUGH GENERATION MEAN ANALYSIS IN OKRA (Abelmoschus esculentus (L) Moench)

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Title GENE EFFECTS, HETEROSIS AND INBREEDING DEPRESSION STUDIES THROUGH GENERATION MEAN ANALYSIS IN OKRA (Abelmoschus esculentus (L) Moench)
 
Creator PATEL KALYANJI DEVASHI
 
Contributor Barad A.V.
 
Subject Okra
HORTICULTURE
 
Description The present investigation was carried out with a view to generate information on gene action and relative importance of the inheritance, the extent of heterosis and inbreeding depression of fruit yield and its attributes in okra (Abelmoschus esculentus (L) Moench) through generation mean analysis. The experiment material consisted of six basic generations (P1, P2, F1, F2, B1 and B2) of six crosses viz., VRO-5  GO-2, VRO-3  VRO-5, KS-404  HRB-108-2, D-1-87-5  KS-404, Arka Anamika  Parbhani Kranti and HRB-55  Arka Abhay involving ten diverse parents.
The experiment was conducted in randomized block design with three replications, at the Vegetable Research Station, Junagadh Agricultural University, Junagadh, during Kharif-2003 and Kharif-2004. Eleven important traits viz., days to flowering, days to first picking, plant height (cm), number of branches per plant, number of nodes per plant, internodal length (cm), number of fruits per plant, fruit length (cm), fruit girth (cm), average fruit weight (g) and fruit yield per plant (g) where studied.
Significance difference among various generation means was observed for all the characters in all six crosses in both the years for all the traits studied, except for number of branches per plant in cross D-1-87-5  KS-404, for fruit length in cross Arka Anamika  Parbhani Kranti and HRB-55  Arka Abhay, for average fruit weight in cross HRB-55  Arka Abhay in Kharif-2003 and in cross VRO-3  VRO-5 for number branches per plant and internodal length, in cross VRO-5  GO-2 and D-1-87-5  KS-404 for fruit girth in Kharif-2004, indicating the presence of considerable genetic variability among the generations.
Individual scaling tests viz., A, B, C and 2 values for joint scaling test indicated the presence of epistatis gene effect for most of the traits in all the six crosses in both the years. The mean effect was significant and positive in all the six crosses and was higher in magnitude as compared to additive and dominance effects in both the years. Duplicate epistatis was predominant in most of the characters in all the six crosses in both the years, except for days to flowering in cross D-1-87-5  KS-404 and for average fruit weight in cross VRO-3  VRO-5 in Kharif-2003 and in cross KS-404  HRB-108-2 for days to first picking in both the years indicating that complementary gene effects were prevailed.
Study of gene action revealed that both additive and non-additive components of genetic variation were found important for the inheritance of yield and its attributes. However, fixable components of genetic variation i.e. additive (d) and additive  additive (i) were observed in cross VRO-5  GO-2 for number of nodes per plant and internodal length; in cross KS-404  HRB-108-2 for number of nodes per plant and in cross D-1-87-5  KS-404 for number of fruits per plant. Under this situation the pedigree method of breeding would be useful. The rest of the characters in respective cross combinations showed additive and non-additive type of gene effects. These
traits would be possible to improve by either recurrent selection or biparental mating system in segregating generations followed by selection.
All the three types of gene actions viz., additive (d), dominance (h) and epistatic gene effects [additive  additive (i), additive  dominance (j) and dominance  dominance (l)] were involved in the inheritance for internodal length in cross VRO-5  GO-2, for number of nodes per plant in cross KS-404  HRB-108-2 and for fruit length in cross D-1-87-5  KS-404 in both the years indicated that these three types of gene effects were important for these traits in respective crosses.
Relative heterosis was found significant and positive in cross KS-404  HRB-108-2 for number of nodes per plant, number fruits per plant, fruit length, fruit girth, average fruit weight and in cross VRO-5  GO-2 for number of fruits per plant, average fruit weight and fruit yield per plant in both the years. The significant and positive heterobeltiosis was observed for fruit length and fruit yield per plant in cross KS-404  HRB-108-2 and cross VRO-5  GO-2 in both the years.
In most of the crosses inbreeding depression was observed lower (opposite direction) indicating heterotic effects on F1 generations, because of F2 were decreased. Marked reduction was observed in F2 performance for most of the characters. Likewise heterosis and inbreeding depression were also varied in degree and direction from cross to cross.
It can be concluded that all the three types of gene effects i.e. additive, dominance and epistatis were observed for fruit yield and yield attributes in okra.Thus, the only available methodology is progeny selection, which may first exploited the additive gene effects and than intermating in F2 and back cross generation can increase the frequency of desirable recombinant.
 
Date 2016-09-08T15:34:43Z
2016-09-08T15:34:43Z
2006-07
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/76135
 
Language en
 
Format application/pdf