AGRONOMIC PERFORMANCE OF FIVE SORGHUM VARIETIES IN A HUMID TROPICAL ZONE AS INFLUENCED BY FERTILIZER RATES

Abstract

The phenology, growth and yield performance of four new varieties of sorghum as influenced by NPK 15:15:15 rates were evaluated in Awka, Anambra State Nigeria, a humid tropical zone. The new varieties, Improved Deko, SK-5912, KSV-8 and CSR-01 were evaluated alongside BidaLocal, an existing Nigerian sorghum landrace whereas NPK rates comprised 0, 200 and 400kg/ha. Experimental design was 3 x 5 factorial experiment in randomized complete block design(RCBD). The findings showed significant (P<0.05) interaction effect on phenology of sorghum. All the new varieties significantly flowered and matured earlier than the landrace. Earliestflowering (≈ 69 days) and grain maturity (≈ 111 days) were recorded in Improved Deko across the NPK rates whereas latest flowering (≈ 114 days) and harvest (≈ 154 days) were observed in Bida local. This implied that the Improved Deko flowered (45 days) and matured (43 days) earlier than the Bida Local across the NPK rates. Bida Local produced more number of leaves with wider stems than the new varieties especially at 90 days after planting while fewest number of leaves and narrowest stems were observed in Improved Deko. Although there was a progressive increase in growth (plant height, number of leaves, stem girth) with increase in NPK rates but the mean values recorded with 200 kg/ha NPK application were significantly at par with those obtained with 400 kg/ha NPK application. Highest panicle weight (67.5 g/plant) and grain yield (2.33 t/ha) were significantly (P<0.05) recorded in SK-5912 when the variety received 200 kg/ha NPK. This grain yield (2.33 t/ha) from SK-5912 was higher than the world average sorghum production (1.45 t/ha) Varieties SK-5912, KSV-8 and CSR-01 and Improved Deko had 145.84%, 50.26% and 35.09% grain yield increase with 200 kg/ha NPK when compared to the local variety. The results obtained from the study showed that SK-5912, KSV-8 and CSR-01 sorghum varieties can adapt favourably to a humid region of Awka agricultural zone of Anambra State, Nigeria especially when the soil is amended with 200 kg/ha NPK.