Genetic Constitution of Multigenic Traits in F2 Populations of Intrahirsutum Crosses

Genetic analysis for quantitative and qualitative traits of valuable field crops is vital technique to facilitate plant breeders in predicting breeding behavior of the succeeding filial generations. Eight F2 populations along with their five parental cultivars were studied so as to work-out genetic analysis like, genetic variance (σ2g), phenotypic variance (σ2p), heritability percentage in broad sense (h2) and genetic advance (G.A.) at 10% selection pressure. The experiment was laid out in a randomized complete block design with four replications during 2012 at the Botanical Garden, Department of Plant Breeding and Genetics, Sindh Agriculture University Tandojam. The analysis of variance revealed significant differences among F2 populations for all the multigenic traits studied which suggested that the breeding material is worth for selection of desirable plants from subsequent segregating generations. On an average, F2 progenies gave higher values for almost all the traits which could be either due heterotic effects or transgressive segregants developed through recombination of genes. On the basis of mean performance, parental cultivars CRIS-134 recorded medium-taller plants, produced higher sympodial branches plant-1 and formed more bolls plant-1, while NIAB-78 weighed bigger bolls and gave maximum seed cotton yield plant-1; yet Sadori ginned higher lint% and measured longer staple length. Results thus revealed that these three cultivars are the potential parents for hybridization and selection programs so as to improve various traits of economic importance in cotton. Genetic analysis suggested that F2 population from cross CRIS-134 x Sadori exhibited higher heritability estimates associated with greater genetic advances for sympodial branches plant-1 (h2=69.06%, GA=12.05) and staple length (h2=76.91%, GA=13.58); while progenies from Chandi x Sadori cross manifested maximum heritability estimates and higher genetic advances for bolls plant-1 (h2=75.60%, GA=26.98), seed cotton yield plant-1 ((h2=74.06%, GA=81.45), lint% ((h2=80.41%, GA=18.44) and seed index (h2=72.97%, GA=2.70), respectively. Genetic analysis as a whole indicated that quite a number of F2 progenies expressed high heritability estimates coupled with greater genetic advances revealed that such progenies possess additive genes, hence are potential breeding material for selection of desirable plants from succeeding segregating generations.

کلیدواژه ها:

Genetic analysis ، Yield and fibre traits ، Intrahirsutum F2 populations