Vegetos

Abstract

Present investigation assess the performance of 9 Bt transgenic cotton hybrids, viz. Four Bollgard I (Ankur 2226 Bt, JKCH 1945 Bt, NCEH 9 Bt and RCH 134 Bt), five Bollgard II (RCH 134 BG II, Tulasi 9 BG II, Ankur Jassi BG II, MLCH 315 BG II and KDCHH 441 BG II) along with one non-Bt hybrid (LHH 144) for insect pests, diseases, yield and fibre quality parameters at Cotton Research Farm, Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana. Overall mean boll infestation was comparatively low in Bt cotton hybrids ranging from 0.0 to 1.51 and 0.0 to 0.92 per cent on boll and loculi basis, respectively as against 12.37 and 6.70 per cent in non-Bt check LHH 144. Evaluation of Bt hybrids against cotton leaf curl disease was carried out under screen house conditions at Ludhiana and under field conditions at Regional Station, Abohar along with local non Bt variety F 1861 (resistant check) and RS 921 (susceptible check). Among all genotypes, only LHH 144 was found to be resistant to cotton leaf curl disease. All the hybrid entries showed resistance to bacterial blight due to low incidence, however found susceptible to fungal foliar disease. Therefore selection towards CLCuD and sucking pest tolerance in transgenic hybrids is crucial to realize the full potential of transgenic plants for sustainable cotton production. Among all hybrids, RCH 134 Bt recorded the highest mean seed cotton yield (2342 kg/ha) as compared to other test Bt hybrids (851 to 2083 kg/ha) and non-Bt hybrid, LHH 144 (1491 kg/ha). All Bt hybrids were superior to non-Bt LHH 144 with 8 to 57 per cent increase in yield except Ankur 2226 Bt, JKCH 1945 Bt, NCEH 9 R Bt, MLCH 315 BG II and KDCHH 441 BG II which were inferior suggesting that selection of superior genotypes with better yield characteristics is vital for developing transgenic cotton.