Evaluation of Lowland Rice ‘NERICA Varieties' and their Ratooning Ability in an Inland Valley.

Abstract
Triple cropping in inland valleys (IVs) is technically possible; however, the third crop between main crop and dry season cropping was not economically viable because of poor crop establishment due to soil inundation. Identification of appropriate technology such as ratooned crop is likely to fit into the niche that exists between lowland crop and vegetable. Field experiment was conducted at the University of Agriculture, Abeokuta, Nigeria in 2007 to evaluate the performance of the main and ratoon crop of selected high yielding lowland rice varieties of ‘New Rice for Africa’ (NERICA) (Oryza sativa L.) in lowland rice–ratooned rice–vegetable sequence. The first, second, and third crops in the sequence was planted or cut in May, September and December, respectively. The experiment was laid out in Randomize Complete Block Design in three replicates. The lowland rice varieties used were NERICA-L 19, NERICA-L 20, NERICA-L 22, NERICA-L 24, NERICA-L 25, NERICA-L 26, NERICA-L 41, NERICA-L 42, NERICA-L 44 and NERICA-L 47. The ten varieties were sown on the 16^th May, 2007 and harvested between 4^th and 16^th September, 2007. The culms of the harvested rice were cut at 5 to 10 cm above the soil surface between 5^th and 17^th August 2007 to stimulate ratooned crop growth. The plant height, panicles m^-2, number of grains panicle^-1, number of days to 50% flowering and grain yield of the main crop were varied. The grain yields of main rice crop range between 5.00 and 7.31 t ha^-1. The NERICA-L 41 and NERICA-L 42 varieties top the others in grain yield while NERICA-L 47 had the least. The plant height, panicles m^-2, number of grains panicle^-1, number of days to 50% flowering and grain yield of ratooned crop were at variance. The grain yields of ratooned crop range between 0.96 and 4.27 t h^-1. The total grain yield in 7 months of both main and ratooned crop ranged between 6.65 and 11.58 t ha^-1. Based on this evaluation, ratoon crop appeared to be viable technology that could fit into the existing niche and consequently increase the productivity of IV.