Agronomic Assessment of Upland Rice Varieties under Unpredictable Rains in the Semi-Arid Conditions of South-Western Agro-Ecological Zone of Uganda

摘要

This paper examined agronomic performance of three upland New RICE for Africa (NERICA) varieties promoted by the Government of Uganda in its efforts to improve household food and income security among smallholder farmers. Three rain-fed experimental trials were conducted on station at Mbarara Zonal Agricultural Research and Development Institute (MBAZARDI), with semi-arid climate conditions typical of more than 50% of the South-Western Agro-Ecological Zone (SWAEZ) of Uganda. The experimental trials were established in the long rain seasons that often occur in September-December period. But results for only one successful long rain seasonal trial of 2010 are presented in this paper. Successful experimental trial for upland NERICA had an average precipitation of 130 mm that was well distributed especially from booting stage, which is the most sensitive growth stage for upland NERICA. During the growth period, NERICA 1 and NERICA 4 were significantly taller (p < 0.05) than NERICA 10. NERICA 4 had the highest yields: two-folds that of NERICA 1, but four-folds lower than that obtained in Namulonge Crops Resource Research Institute (NACRRI), the breeder station for NERICA in Uganda. Grain yields of NERICA 4 were also below the national average of rice productivity estimated at 2.5 t·ha~(-1). Although, NERICA 4 ranked top in terms of grain yields among the tested upland NERICA varieties and therefore, most possible candidate for smallholder rice farmers in the humid parts of the SWAEZ, it called for more breeding for upland NERICA varieties with traits that could increase their tolerance to low soil moisture most prevalent in the SWAEZ.