| dc.description.abstract | Maize is a priority staple food crop in Rwanda and helps farmers to generate income through the surplus sales; despite its low yields of 2.2 t/ha compared to 5.5t/ha worldwide. With the aim to participate in maize grain yield increase, the specific objectives of this research were: (1) to determine the effect of varying N, P, and K fertilizer rate on growth and yield of selected maize varieties and (2) to determine the effect of varying plant density on growth and yield of selected maize varieties. The study was conducted in eastern Rwanda in Bugesera district in two different sites. Field layout was RCBD with 3 replications under 2 x 3 x 4 factorial arrangement. Plant material were RHM 104 hybrid (V1) and ZM 607 OPV (V2). The planting densities were 83,334 plants/ha (D1), 68,334 plants/ha (D2) and 53,334 plants/ha (D3: control recommended by breeders). The fertilizer rates per hectare were NPK 175-68-68 (R1), NPK 150-59.5-59.5 (R2), NPK 97-51-51 (R3) and the control without NPK application (R4). The crop was gown from October 2017 to March 2018. Planting was done in a plot of 5 m x 4.5 m with 2 seeds/hill which were later thinned to one plant/hill. The distance between rows was 0.75 m with 32 hills/row, 26 hills/row and 20 hills/row for D1, D2 and D3 respectively. The data were analyzed using genstat 15th edition and mean were separated using LSD. Significant difference was observed between sites on plant height, ear height, number of ear harvested, grain moisture at harvesting, and grain yield. Observed interactions were planting density x fertilizer rate on days to anthesis and silking; variety x planting density x fertilizer rate on ear height, site x variety x fertilizer rate on grain moisture at harvesting and variety x planting density on grain yield. RHM 104 hybrid variety tolerated higher plant population than ZM 607 OPV and gave the highest grain yield, above 10 t/ha, with planting density of 68,334 plants/ha. This research revealed the possibility to increase grain yield through increased planting density up to 68,334 plants/ha using RHM 104 hybrid variety. Further research is needed toward site specific fertilizer recommendation and crop management for maximum agronomic efficiency. It is necessary to undertake other researches on all varieties recently released by RAB to determine varieties which are most tolerant to high planting densities and therefore giving highest grain yield | en_US |
