Heterosis studies in GMS based diploid cotton.

A study of heterosis over better parent and checks was carried out during 2005-06. GMS based hybrids were generated byutilizing 18 genetic male sterile lines of G. arboreum and 3 testers of G. herbaceum. The hybrids exhibited high heterosisover better parent and varietal check Rahs-14, while they also exhibited considerable heterosis over standard check,Chamtkar-222 and varietal check, DLSa-17, for seed cotton yield (kg/ha). The two hybrids, Million-GMS × Jayadhar andGAKA-423 × H-221 which were recorded significant positive heterosis for seed cotton yield(kg/ha) over standard checkChamatkar-222 also have significant positive heterosis for yield component trait like boll number and fibre quality traits like,2.5 per cent span length and fibre strength over all the checks. Only few hybrids recorded significant positive heterosis foreconomic traits like seed index, lint index and ginning outturn, while many hybrids recorded significant positive heterosis forfibre quality traits like 2.5 per cent span length and fibre strength over standard check, Chamatkar-222 and varietal checkRahs-14. The hybrids, GMS-4 × DDhC-11, GAKA-8614 × DDhC-11 and GMS-4 × DDhC-11 recorded significant positiveheterosis over standard check, Chamatkar-222 and varietal check Rahs-14 for 2.5 per cent span length and fibre strength.