Heterosis for physiological traits in hybrid rice (Oryza sativa L.)

Abstract

Hybrid rice (Oryza sativa L.) has unique advantage of better physiological efficiency. However the information on physiological traits in this crop are limited. Present study was therefore undertaken using five male sterile lines viz., PMS 9A (L1), PMS 10A (L2), V 20 A (L3), IR 58025A (L4) and IR 62829A (L5) and seven pollinator varieties viz., BR 736-20-3-1 (T1), IR 31406 (T2), IR 50400-64-1-2-2-22 (T3), IR 8866-20-3-1-4-2 (T4), MDU 3 (T5), MDU 4 (T6) and Pomi (T7). The 35 hybrids obtained in a line x tester mating fashion were evaluated in RBD for the nature and magnitude of heterosis for four physiological traits including leaf areas index (LAI), total chlorophyll content (TCC) at maximum tillering stage, total dry matter accumulation (TDMA) and harvest index (HI) after maturity along with grain yield per plant (GYP). The hybrids and parents were raised at Agricultural College and Research Institute, Madurai, Tamil Nadu during Rabi 1996-97 by adopting standard agronomical practices. Relative heterosis (RH), heterobeltiosis (HB) and standard heterosis (SH) were calculated and significance of heterosis was tested using 't' test. This information on the extent of heterosis would help in the choice of the best crosses for commercial exploitation.