ESTIMATION OF GENETIC VARIANCE COMPONENTS AND IDENTIFICATION OF TRANSGRESSIVE SEGREGANTS FOR TWO INTRASPECIFIC EXTRA-LONG STAPLE COTTON CROSSES

Abstract

The available genetic variability in the studied germplasm may be used for direct selection or hybridization program. The experimental material comprised of F1 and F2 populations along with their respective parents of two intra-specific cotton crosses belonging to G. barbadense L., to estimate heritability, genetic advance as percent of mean and transgressive segregation for boll weight, seed cotton yield per plant, lint yield per plant, lint percentage, fiber length, fiber strength, fiber fineness and uniformity ratio. Variance of parents was lowest for all the studied traits suggesting thereby homogeneity within parents. But it abruptly increased in F2 population due to release of segregation variability. Most of the studied traits showed high heritability coupled with low genetic advance as percent of mean which indicated the predominant role of non-additive gene action in the expression of these traits. Both skewness and kurtosis had lower values and differ in the two crosses for studied traits. Lint yield / plant and lint % showed negative skewness sign and micronaire value had positive kurtosis sign for the two studied crosses. The two crosses had thrown maximum number of transgressive segregants over better parent for fiber length followed by micronaire value and boll weight, while, uniformity ratio had lowest number of transgressive segregants. The most promising transgressive segregants selected in F2 generation also to breakdown the negative correlation between high yield and fiber quality traits. The cotton breeder could be used indirect selection to improve these traits. These desirable selected plants had higher threshold value for the eight studied traits. A track on these transgressive segregants should be maintained and forwarded to further generations up to reach to homozygosity. Most promising one could be used in further breeding programme.