GENETIC ANALYSIS AND PREDICTION OF NEW RECOMBINATION IN SOME COTTON (G. barbadense L.) CROSSES

Document Type : Original Article

Abstract

Improving cotton breeding programme must depend on the amount ofgenetic variability between the parental genotypes, which is the main sourceof genotypic variation among the progeny. The present study was undertaken for the estimation of genetic variability, genetic components and heritability for some yield characters in F2, F3 and F4 generations derived from two cotton crosses. Estimated Prediction of new recombinant in F3 generation and selection was done on F2 to select the most promising plants and the most superior F3 families and plants within each selected family. The results showed some genetic variation among three studied generations, which reflect genetic variability between studied generations. Dominance genetic variance was more important than additive genetic variance in most studied characters. These results indicated that these characters are controlled by non-additive gene type. The analysis of variance for F3 generation showed significant differences between F3 families and it’s greater than within families
in all the studied characters over the two cotton crosses, which show presence of high genetic variability in F3 generation. This reflects low values of intra-class variability. So, selection is more effective between families rather
than within families. Correlation and regression results between generations showed that F2 was not good indicator of F3 progeny, while this trend changesfrom F3 to F4 generations. Prediction for new recombinant failing outside parental range through F3 generation was higher for all the studied characters. Realized selection differential was higher between and within
selected F2 plants and F3 families. So, the grand mean values of these selected plants and families were higher than grand mean of F2 and F3 population. Selection between segregating generations coupled with high heritability is a good indicator for selecting promising plants in F2 generation and most superior families within F3 families and within each family.

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