Effect of detopping on forage and grain yield of rice under agro-climatic conditions of D.I. Khan.

摘要

To study the effect of detopping on forage and grain yield of rice, an experiment was conducted at the Research Area, Faculty of Agriculture, Gomal University, D.I.Khan during kharif 2004 in a randomized complete block design with three replications. The experiment consisted of six treatments viz., Control (T1), detopping at 22 days after treatment (DAT, T2), 29 DAT (T3), 36 DAT (T4), 43 DAT (T5), and 50 DAT (T6). The effect of detopping was significant on all the yield and yield components, of rice except 1000-grain weight. In respect of all the six treatments, the highest plant height (125 cm), number of productive tillers hill-1 (9), panicle length (23.4 cm), number of spikelets panicle-1 (106.8), number of grains panicle-1 (90), number of sterile spikelets panicle-1 (18), 1000-grain weight (22 g), biological yield (9.6 t ha-1), straw yield (5.6 t ha-1), grain yield (4.1 t ha-1) and harvest index (42.70%) were obtained from control (no detopping). The yield and yield contributing characters decreased by detopping when compared with control. The results revealed that the highest green fodder yield (3.5 t ha-1) was obtained from foliage cutting at 50 DAT, and with the lowest grain yield (3.0 t ha-1). The highest grain yield (4.1 t ha-1) was recorded in the control, which was not significantly different from T2, T3 and T4. Detopping at 36 DAT (T4) gave an identical grain yield (3.5 t ha-1) to that of control plot with higher additional forage yield (2.4 t ha-1). Hence, it is concluded that detopping at an early vegetative stage of crop growth could produce almost similar grain or seed yield to that of control plot with the additional forage yield, and reduced lodging in case of excessive vegetative growth..