Abstract

                                Field experiments were conducted using two rice genotypes with differential root activity. The genotype, TNRH 180 rice hybrid performed better with higher root activity than the variety PMK (R) 3 in both dry and summer season. Connecting irrigation methods, sub-surface drip irrigation at 125 % PE water level treatment maintained enhanced root activity at all the phenophases studied. The grain filling rate was positively correlated with root activity expressed as α-naphthylamine oxidation ability (RA) per gram of fresh root (RA ), RA per spikelet (RA grain RA per sink capacity (RA). It is inferred that RA could be an effective parameter that can be sink grain altered to improve grain filling and test weight in rice for enhanced productivity in surface and sub-surface drip irrigated conditions.

Key words : Surface and sub-surface drip, Aerobic rice, Grain filling, Root activity.