VARIATION IN F2 POPULATION FOR EXTRA LONG X LONG STAPLE CROSSES IN EGYPTIAN COTTON

doi:10.12816/ejpb.2016.361007

VARIATION IN F2 POPULATION FOR EXTRA LONG X LONG STAPLE CROSSES IN EGYPTIAN COTTON

Document Type : Original research

10.12816/ejpb.2016.361007

Abstract

Successful cotton breeding programs focus initially on developing new genotypes with high yields and improved fiber quality. The main aim of this work was to determine the inheritance of yield and fiber quality of an extra long staple (ELS) variety in two crosses with long staple parents and to determine the variability in F₂ populations. Hybridization between the Egyptian extra-long staple (ELS) cotton variety Giza 88 as a female parent pollinated by the long staple varieties, Giza 86 in cross I and Suvin in cross II in 2014 season. Parents and both F₁ and F₂ generations were grown in a randomized complete block design during 2016 season at Sakha Experimental Station Farm, ARC. Data were recorded on individual plant basis for the studied traits. The studied genotypes, parents and both F₁ and F₂ generations were significantly different for all the studied traits, reflecting the genetic diverse back ground of these parents. The variation due to parents vs. F₂ generation was also highly significant for most of the studied traits. The long staple varieties (Giza 86 and Suvin) had the higher mean performance for yield and its component traits whereas the extra long staple variety (Giza 88) gave the highest values for fiber properties, both F₁ and F₂ were intermediate. F₂ population produced greater yields of seed cotton and lint cotton with heavier bolls and higher lint% as compared to the ELS parent. Whereas, fiber properties for F₂were not improved over the ELS parent. With regard to the induced variability, F₂ population showed the wider ranges of distribution, higher variance and higher C.Vs as compared with the parents for all traits in the two crosses reflecting the efficiency of artificial hybridization in inducing variability in the studied genotypes. Cross II gave higher variance and C.Vs than cross I for most traits indicating that the introgressed variety Suvin induce more variability when it crossed with the Egyptian variety than the cross between the two Egyptian varieties. Broad-sense heritability (h²_b) was high for fiber traits than yield and its component traits traits. High h²_bvalues were recorded for fiber length in both crosses; moderate values were recorded for lint%; fiber fineness; strength and uniformity. Low values were observed for boll weight, seed index seed cotton and lint yields. Mid-parent heterosis in F₁populations was low for most traits. Inbreeding depression % showed positive values for most of the studied traits. All traits in both crosses showed partial dominance, the direction was toward the higher parent for most traits. Neither of the F₂ populations in both crosses exceeded the high parental mean for any economical trait (lint yield and fiber quality) although some of F₂ individual plants gave higher yield and/or fiber quality than the parents. The value of these populations likely will be derived from the selected individual plants to be used in a pedigreed breeding program.

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