Genetic Variability Inheritance and Molecular Studies in Colour Cotton Gossypium spp

Abstract

newlineThe present investigation was conducted during the kharif seasons of 2016-17 and newline2017-18 at the Agricultural Research Station, Dharwad Farm. The present study was aimed at newlineidentifying the promising stable colour-cotton genotypes, deciphering the genetics underlying newlinethe fiber colour and molecular studies related to fiber colour in colour-cotton. newlineAnalysis of variance revealed significant variability among the genotypes for all yield, newlinefiber quality traits and fiber colour with moderate heritability. All agronomic traits had newlinesignificant direct effect and positive correlation with seed cotton yield. Fiber colour trait was newlinenegatively associated with productive and fiber quality traits and fiber strength could be used newlineas a negative surrogate for indirect selection of fiber colour. The genotypes MB-535-1 newline(Medium Brown), DB-9-1, DB-57-2 (both Dark Brown), C-318-1 (Cream) and G-4-1 (Green) newlinewere identified as promising high yielding genotypes. Inheritance showed that brown fiber newlinecolour and almond fiber colour were found to be dominant over their white counterparts. But newlinegreen fiber colour was dominant over the white colour. Brown colour of lint is mainly newlinecontrolled by two genes with duplicate dominant interaction. Almond and green colour lint newlinewas inherited as single gene with biallelic nature. Histological studies for fiber colour showed newlinethat pigments in brown colour were proanthocyanidins which belong to the flavonoid group. newlineThe molecular marker DSSR-8 was found to be associated with the brown and almond colour newlinethrough bulk segregant analysis. None of the markers showed polymorphism for white and newlinegreen bulks in both interspecific and intraspecific crosses. The gene expression studies of newlinecandidate colour genes showed that all five structural genes were up regulated in brown newlinecotton fiber followed by in green and white cotton at all the boll development stages. Genetic newlineengineering strategies have to primarily focus on modifying the GhANS and GhANR genes to newlineimprove the intensity of pigmentation of cotton fibers.