USING BIPARENTAL MATING DESIGN TO BREAKUP UNDESIRABLE LINKAGE GROUPS AND OBTAIN NEW RECOMBINATIONS IN COTTON (G. barbadense L.)

Document Type : Original research

10.12816/ejpb.2023.301678

Abstract

The present experiment was carried out at Sakha Agricultural Research Station, Kafr EL-Sheikh Governorate, Cotton Research Institute, Agricultural Research Center, Egypt, during 2021 and 2022 growing seasons. The aim of study was to breakup undesirable linkage groups and obtain new recombinations in cotton. The genetic materials included the cross combination belong to Gossypium barbadense L. (Giza 68 x CB58). The data indicated significant or highly significant mean squares for all studied traits, except seed index. Significant and highly significant variances among biparental families for all studied traits were found, except for seed index and uniformity ratio, indicating presence a lot of genetic variation among families. Results showed that desirable means values of the BIP for all studied characters, indicating possible accumulation of favourable genes due to breakage of undesirable linkage by intermating. The results indicated higher values for PCV as compared with GCV for most studied traits due to involvement of high genotypic x environmental interaction effect in the expression of these characters. High broad sense heritability was observed for most studied characters, indicating high magnitude of genetic variability and that environmental influence was low on this studied traits except, seed index and uniformity ratio which are influence with environmental factor ranged from 0.133 and 0.464 respectively. In general, genotypic correlations were higher than corresponding phenotypic correlations indicated that genetic effects were greater than the environmental effects in the expression of the traits. The observed gain in seed cotton yield of best five families ranged from 9.66% to 32.68% for seed cotton yield and from 1.82% to 3.34% for lint percentage while, ranged from 0.59% to 8.34% for seed index. Also, some hybrids gave simile in fiber strength compare with mid-parent. The positive direct effect of lint yield / plant was (1.1035) followed by lint index (0.2433), 2.5% SL (0.1383), fiber strength (0.0949) and boll weight (0.0124). However, the indirect effects of lint yield on seed cotton yield via lint index was the highest one (0.1947). Hence selection for these characters would be useful effective for improving seed cotton yield.

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