Evaluation of Long Panicles Lines in Several Environments.

Increasing number of grains per panicles is a strategy followed by the CIAT-FLAR breeding program to increase yield potential in rice. The objective of this study was to evaluate contrasting experimental rice lines and checks in several locations in Colombia and Venezuela for yield, yield components, and agronomic traits.  Twelve genotypes were evaluated in yield trials in CIAT Palmira, La Victoria Experimental Station, La Carolina Farm in Portuguesa Venezuela, and Farm 178 in Calabozo Venezuela during the dry season 2007-2008. Results showed several long panicles lines with higher yields than checks in all locations; however, none of the lines  was superior in all environments due to significant gxe interaction. In general, number of grains per panicles was positively associated with yield, but negatively with number of panicles per square meter indicating compensation between yield components. Also, long panicles lines had higher index harvest in Palmira and higher yields across locations. There was not relationship between number of grains per panicles and stability, some long panicles had high yield but were unstable and some had high yields and were stable.  These results indicate that breeding for more grains per panicle or “paniculas largas” is a correct strategy to increase yield potential in rice; however, it is necessary to take into account the interrelationships and compensations between yield components, to maintain good plant type and short  plant height, lodging tolerance and low sterility. These results suggest that in order to take advantage of the long panicle trait a strategy based on specific adaptation can be more successful.

Key words: Yield potential, long panicles, yield components.