Effect of G. harknessii based cytoplasmic male sterility on seed cotton yield and fibre quality traits in upland cotton (Gossypium hirsutum L.)

To study the effect of male sterile cytoplasm on seed cotton yield and fibre properties of hybrid cotton, five cytoplasmic male sterile lines (A) and their maintainers (B) were crossed with six restorer lines and two types of hybrids i.e. A x R and B x R were developed. The hybrids were evaluated for seed cotton yield, ginning out turn, 2.5% span length, uniformity ratio, micronaire value and tenacity. The results showed that, sterile cytoplasm has detrimental effect on yield of hybrid cotton. The hybrids produced by using restorers with G. harknessii cytoplasm as the female parent showed about 4.76 to 15.63% reduction in yield However, no negative effect was observed for ginning out turn and other fibre quality traits. On the contrary, increased 2.5% span length was observed CMS based hybrids ranging from 0.36 to 15.63 per cent.The reduction in micronaire value was also observed in almost all the A x R hybrids except in one of the cross combinations F 505A x CIR 72. The highest reduction in micronaire value was up to 30% in the hybrid combination Bikaneri Narma A x CIR 32 with sterile cytoplasm. Similarly, increase in tenacity value was noticed in CMS based hybrids, which was also reflected on strength/length ratio.The detrimental effect of sterile cytoplasm on yield could be overcome by using suitable restorer and stable CMS lines, attempting more number of cross combinations to find out the suitable hybrids with high yield potential and better fibre quality with CMS system.