Abstract
Heterosis in the F1 and inbreeding depression in the F2 generation for yield and yield components in three New Plant Type (NPT) x indica [(NPT 89 x IR 36), (NPT 89 x Pusa Basmati 1) and (NPT 63-01 x Pusa Basmati 1)] were studied in a field experiment in Kharif 2002. Significant positive heterosis was seen for plant height, panicle length and grain yield per plant while the traits days to 50 % flowering, days to maturity, number of productive tillers per plant, average grain length, average grain breadth, L: B ratio exhibited a significant negative (but low) heterosis over the better parent in negative direction. A high negative heterosis was observed for number of spikelets per panicle, number of filled grains per plant and sterility percentage. This identifies favourable heterotic combinations that can be exploited in hybrid breeding programme. Heterotic analysis of yield components indicated a new ideotype for rice with medium tall culms, a larger number of productive tillers per plant with more filled grains and greater 100 seed weight.
