EFFECT OF MUTAGENS ON INHERITANCE OF SOME QUANTITATIVE CHARACTERS IN EGYPTIAN COTTON

doi:10.12816/ejpb.2019.256699

EFFECT OF MUTAGENS ON INHERITANCE OF SOME QUANTITATIVE CHARACTERS IN EGYPTIAN COTTON

Document Type : Original research

10.12816/ejpb.2019.256699

Abstract

This study was conducted at Sakha Experimental Station, Agricultural Research Center during three seasons 2017- 2019. The aim was to evaluate the induced variability in some quantitative characters in an Egyptian cotton cross (Giza 86 x Giza 88) using generation mean analysis after treating with 100Gy dose of gamma rays (γ-ray) as physical mutagen and 200 ppm of Ethyl methane sulphonate (EMS) as chemical mutagen, gene effects were determined using means of the six populations: P₁, P₂, F₁, F₂, BC₁ and BC₂to clarify the inheritance of yield, its components and fiber properties. The results indicated that the mutagen treatment decreased the mean performance for most of the studied traits and increased the variability for all traits in M₃ generation. Hybridization increased variability in both of F₂ and the back crosses of untreated populations in M₃ as compared with parents for most of the studied traits. Moreover, crossing the mutagen treated parents increased variability than crossing alone. Highly significant differences were detected among the three treatments tested in this study for most of the studied traits, with the advantageous of the control treatment that gave the best values for all traits while the chemical mutagen treatment (200 ppm, EMS) showed the most depressive effect on the mean performance. Both mutagens were effective in inducing variability as they increased the total variance in both parents as compared to the untreated population for most studied traits, EMS treatment was more effective than γ-ray treatment in this respect. Both additive and dominance gene effects estimated from the six population analysis had important role in the inheritance of the studied traits. Fiber quality traits showed that additive gene effects were significant in all treatments and larger in magnitude than dominant ones, whereas dominance effects were generally larger than additive one in plant height, cotton yield and its components. Epistatic gene interactions additive × additive (i) were significant for the studied traits with a few exceptions, additive × dominance (j) were significant for some of the studied traits and dominance × dominance (l) also showed significant role in inheritance of all traits except for boll weight and lint% in the control treatment. Mid-parents heterosis, recorded significant or highly significant positive heterosis for some traits, whereas the rest cases had highly significant negative heterosis, in most cases, values of heterosis were low in magnitude. Inbreeding depression values were significant and positive for some traits. Phenotypic and genotypic coefficients of variability estimates showed that PCV values were higher than GCV about at least two folds for most traits in all treatments, indicating the environmental important role in the expression of the studied traits. Broad-sense heritability values were generally higher for fiber traits than productivity traits and the control treatment showed higher values than the mutagen treatments, EMS treatment showed the lowest values in this respect.

Keywords