Evaluation for the retention of reproductive structures by Bt and non-Bt intra hirsutum cotton hybrids in different sowing dates and spacings

The retention of the reproductive structures (bolls) was evaluated at 90,120 and 160 days of maturity in eight Bt and non-Bt hybrids from three Private R&D establishments on three dates of sowings (90,120 and 160 days of maturity) and two spacings of 67.5 x 60 cm and 100 x 30 cm. Ankur group Bt hybrids; 651, 2226 and 2534 had reproductive structures retentivity higher than their non-Bt counterpart hybrids in all the three sowings and spacings. However, RCH group Bt hybrids; 134 and 138 had lesser/comparable boll retentivity in first two observations at 90 and 120 days in the earliest and the next sowing. In the last sowing with wider inter row spacing their trend was similar to Ankur group hybrids in the first sowing. MRC 6301 also behaved like RCH group hybrids. Bt hybrids of all the three establishments had more reproductive structure retentivity than their non-Bt hybrids counterparts in early, closer inter row and wider intra row sowing except for Bt hybrid RCH134 which had the highest bearing in the late sowing with wider inter row and closer intra row spacing. Association study indicated similar trend of boll bearing in Bt and non-Bt hybrids in early sowing and this trend seems to be reverse in later sowings