Synchronized boll development of Bt cotton hybrids and their physiological consequences

The temporal and spatial distribution of fruiting forms, their retention and shedding pattern was studied in field-grown Bt cotton hybrids MECH 12, MECH 162 and MECH 184 and their non-Bt (NBt) counterparts at the Central Institute for Cotton Research, Nagpur, India. Plant phenology in terms of time required for squaring and flowering did not vary significantly between Bt and NBt hybrids. However, boll bursting duration was slightly shorter in Bt plants (51 days) compared to NBt plants (55 days). Bt plants produced nearly 30% less squares, but retained 25% more bolls than NBt plants. The initial few sympodial nodes contained most of the open bolls in Bt plants, while they were mostly barren in NBt plants. This synchronized boll development in Bt plants altered the source