Stability Studies in Cotton (Gossypium Hirsutum L.): Can Stable Performance of Cotton Genotypes in The National Trials be used as Reliability Index in Determining Stable Hybrids?

Performance of genotypes in terms of productivity without stability serves no purpose. In this particular study the issue of stability of hybrids was taken up to see if selection of parents (varietal genotypes) based on stability of performance in national trials can lead to potential and stable hybrids. Consistent performance of G. hirsutum genotypes in the national trials of the All India Coordinated Cotton Improvement Project (AICCIP) with respect to higher productivity and desirable fibre qualities was the major criteria for selecting the eleven G. hirsutum genotypes viz., ARB 904, CPD 803, HAG 1055, H 1284, CSH 2572, CCH 1386, LRA 5166, MCU 5VT, CCH 510, 701M and Surabhi constituting a 11 x 11 half diallel crossing programme. Fifty five intra-hirsutum hybrids developed in this fashion were evaluated for their phenotypic stability with respect to seed cotton yield and fibre quality traits especially fibre strength over three diverse environments viz., Siruguppa (E₁), Bheemarayanagudi (E₂) and Dharwad (E₃) of Karnataka state during kharif 2006–07 along with the commercial check Bunny. The results revealed significant differences among the genotypes at one per cent level of probability for both seed cotton yield and fibre strength. While the environmental component was substantially larger than genotypes and genotype x environment interaction for both the traits, the mean squares due to pooled deviations which indicate the non-linear or unpredictable portion of G x E interaction was found to be highly significant for seed cotton yield, but was found to be non-significant with respect to fibre strength. Among the varietal genotypes used in the study, CPD 803, ARB 904, HAG 1055 and LRA 5166 contributed significantly for higher seed cotton yield and fibre strength as revealed by high gca values. Besides, these four genotypes resulted in better stable hybrid combinations with desirable fibre strength to length (S/L) ratio.¹The results further revealed that, certain varietal genotypes from south zone particularly, Dharwad region viz., CPD 803, HAG 1055, ARB 904 and LRA 5166 contributed to the higher productivity and fibre strength, thus illustrating the utility of location specific bred material for subsequent development of cotton hybrids with a blend of higher seed cotton yield and better fibre quality parameters. Among the environments, E₂ had higher environment index value than that of E₃ and E₁.