Variable radiation use efficiency in rice cultures grown at different locations

Variation in radiation use efficiency (RUE) amongst 81 rice cultures was assessed at Hyderabad, Maruteru and Pattambi locations. The RUE was computed for each culture at panicle initiation stage (RUE_pi) and at physiological maturity (RUE_m) for each location. RUE_pi and RUE_m differed significantly amongst cultures and also between locations. The interaction between location and cultures was also found to be highly significant. The mean RUE_pi for all the cultures was 1.08, 0.56 and 1.22 g MJ⁻¹, respectively, for HYD, MTU and PTB. The average RUE_m estimated was 0.37, 0.60 and 0.93, respectively, for HYD, MTU and PTB. Out of the 81 rice cultures, very few entries consistently showed high RUE at all the three locations and at both the stages. The cultures IET 21023 and IET 20986 recorded higher, though not the highest, RUE, at panicle initiation and maturity stages at all the three locations and produced TDM and grain yield higher than the mean TDM and grain yield for all the test cultures.