Ratooning ability and its effect on grain yield of upland Nerica rice varieties in Central Kenya

Abstract Field experiments were conducted at Mwea Irrigation Agricultural Development (MIAD) Centre in central Kenya (0o 41'S, 37o 20'E, 1159m) to assess rice ratooning ability and its effect on grain yield. Four upland NERICA (NERICA 1, 4, 10 and 11) and one local Oryza sativa (Duorado precoce) rice varieties were planted in randomized complete block design with three replicates. The main crop was harvested at maturity after which the tillers were hand cut to stubble of about 15cm tall. The stubbles were left to grow without application of any further input until the ratooned plants were ready for harvesting. Ratooning ability among the NERICAs ranged from 26% (NERICA 1) to 39% (NERICA 4) while Duorado precoce recorded the lowest (19%). Total grain yield (main crop plus ratoon) differed significantly (p<0.05) among the rice varieties with NERICA 4 attaining the highest total yield (6206kg ha-1) while the local variety Duorado precoce attained the lowest (3376kg ha-1). NERICA 4 and NERICA 10 recorded remarkable yield increase of more than 1500kg ha-1 (the average yield of upland rice in Subsahara Africa) with no additional input. NERICA 4 recorded the highest grain yield and ratooning ability and is therefore recommended for Central Kenya though the yield and ratooning ability of the other three NERICA varieties were also encouraging. Results of this study can serve as a guide on how ratooning can be used to maximize upland rice yield in Central Kenya.