Development and evaluation of India's first intraspecific cotton recombinant inbred mapping population for extra-long staple fibre traits.

Fibre quality improvement in is one of the long thought objectives for sustainability of cotton improvement. The efforts to transfer alleles in to for enhanced fibre quality is still under process across the world. To meet the future fibre quality demand in India, here we report development of recombinant inbred mapping population that has huge potential for precise mapping of extra-long staple traits. The two-location evaluation and variability analysis for extra-long staple traits such as fibre length (24.91 to 34.06 mm), fibre strength (25.02 to 35.86 g/tex), micronaire (2.89-4.57), uniformity index (64.08-98.83), fibre elongation (5.37-6.60) and maturity ratio (0.48-0.76) were highly satisfactory. The principal component analysis indicates that the principal component-1 explaining 23.12% variance had maximum values of Eigen vectors explained by fibre strength (-0.464), length (-0.469), elongation (-0.448), maturity ratio (0.312) and micronaire value (0.306) indicating the worth of the population for which it was developed. The correlation analysis indicated that the fibre length and strength could be simultaneously improved without any impact on seed cotton yield since both traits were positively associated with each other and also showed nonsignificant association with seed cotton yield. A total of 255 recombinant inbred lines (RILs) showed normal distribution from both Z-score of skewness/kurtosis analysis and quartile-quartile plots indicating that they can be readily utilized for genotyping with latest available technologies such as genotype-by-sequencing for effective mapping of extra-long staple traits in cotton.