GENETICS OF YIELD AND FIBRE QUALITY TRAITS IN AMERICAN COTTON (GOSSYPIUM HIRSUTUM L.)

摘要

Fifty five genotypes of American cotton (G hirsutum L.) comprising of 10 parents and their 45 hybrids produced in a diallel fashion (without reciprocals) were evaluated for estimating the genetic variability, heritability and genetic advance in four different environments for yield and yield components besides fibre quality traits. The El- Normal sowing (15th July) - Irrigated was foun^l to be the most favourable environment for majority of the characters, while E2 - Delayed sowing (l5th August) - Rainfed was considered to be poor environment. The variation in the magnitude of estimates of genetic parameters for all the characters under different environments suggests the profound influence of em irohment on the character expression. The PCV and GCVwas high for seed cotton yield per plant. The PCV was greater than GCV for all the characters. The GCV/PCV ratio was high for 2,5% span length and bundle strength indicating that these traits were not much influenced by the environment. Heritability estimates were high for ginning percentage, 2.5% span length, bundle strength and seed cotton yield indicating the amenability of these traits in selection process. High heritability coupled with high genetic advance for ginning percentage, 2.5% span length, bundle strength and seed cotton yield indicates the operation of additive gene action in the inheritance of these traits. Number of seeds per boll, seed index and oil percentage showed low heritability as well as low genetic advance besides narrow range of variability indicating the predominance of non additive gene action.