Rice (Oryza sativa L.) establishment methods under irrigated and rain-fed lowlands of Kenya: Effect on growth and yield

An experiment was conducted at Ahero and Mwea during July 2017 to January 2018 season; to assess effect of direct seeding (DS) and transplanting (TP) on growth and yield of four rain-fed ( NERICA1 & 4, Komboka, MWUR4) and four irrigated (SARO5, Komboka, NIBAM11, MWIR2) varieties, on Kenyan lowlands. A split plot on randomized complete block design (RCBD) was used with three replicates; three seeds hill-1 were dibbled, later thinned to one on DS plots, one seedling was transplanted on TP plots. A (20×15) cm spacing used on both DS and TP plots. Data was subjected to analysis of variance, separation of means using Turkey's test at 5% probability level. Results on plant height, productive tillers hill-1, grain weight hill-1, 1000 seed weight, yields (rain-fed) showed non-significance (p> 0.05). Days to flowering onset (rain-fed) had significant differences on DSR and TPR. Productive tillers hill-1 (Irrigated) were significant (p<0.05) while grain yield, grain weight hill-1, 1000 seed weight, days to flowering onset (irrigated) were not significant (p>0.05). Grain yield (t ha-1) on rain-fed varieties indicated TP-Komboka (5.6), TP-NERICA1 (4.6) compared to Komboka and MWUR 4 (DS) at 4.9 and 4.3 respectively. Grain yield (t ha-1) (irrigated) had no yield gain on either TP or DS though they differed significantly with NIBAM 11 and MWIR 2 (TP) at 4.9 and 6.9 while DS- (MWIR2 and NIBAM11) at 5.9 and 4.8 respectively. Harvest index positively correlated to grain yield (rain-fed; r=0.693, p<0.001) (irrigated r =0.696, p<0.001). Variable costs were TP (KES: 81,850) compared to DS (KES 61,900). Although DS yielded less compared to TP, the aspect of water and labour saving would motivate its wide adoption contributing to enhanced rice productivity.