Performance of hybrid napier cultivars under rainfed conditions

Abstract

Hybrid napier, an inter-specific cross between bajra (Pennisetum glaucum (L.) R. Br.) and napier (Pennisetum purpureum Schum.) is a popular fodder grass with high nutritive value and herbage yield. Hybrid napier cultivars perform well under irrigated condition but their performance under rainfed condition is not evaluated. A field experiment was conducted at the College of Horticulture, Vellanikkara to evaluate the performance of 11 popular cultivars under rainfed conditions—CO-2, CO-3, CO-4, KKM-1, Suguna, Supriya, IGFRI-3, IGFRI-7, DHN-6, PTH and PBN-16. Slips were planted at a spacing of 60 cm X 60 cm in June, and growth, fodder yield and nutrient uptake were studied at 45 days interval. The first harvest was taken at 75 days after planting and subsequent harvests at 45 days interval. The cultivars differed significantly in various parameters such as plant height, tillers/plant, leaves/plant, leaf width, leaf length, leaf area index, net assimilation rate, relative growth rate, leaf area ratio, leaf: stem ratio and shoot: root ratio. Four harvests were made, the last being in January. Green and dry fodder yield were maximum during the first harvest, thereafter, yield decreased. In summer, no harvesting was done due to stunting and drying of plants. Among the eleven cultivars evaluated, CO-3 recorded the highest green fodder yield followed by DHN-6. Nutritive values and oxalate content showed significant differences among the cultivars. Crude protein content was maximum in CO-3 and IGFRI-3. In general, CO-3 showed supremacy over other cultivars in terms of overall nutritional quality. Oxalate content, an antinutritive factor, was found to be the highest in Suguna. Nutrient uptake was higher in the first harvest, and CO-3 had the highest nutrient removal. In summer, maximum RLWC was noticed in Supriya and CO-3, and the lowest in IGFRI-3. All the clumps of CO-3, CO-4 and PTH survived the dry periods and maximum mortality was noticed in PBN-16 followed by IGFRI-3, DHN-6, CO-2 and KKM-1. The study revealed that CO-3 is superior to all other cultivars with respect to yield, nutritive value and the ability to withstand drought, and hence, CO-3 is highly suited for rainfed cultivation. Since there was no mortality of clumps for CO-4 and PTH, these cultivars can also be considered. Although DHN-6 showed 25 percent mortality of clumps during summer, as it outyielded other cultivars during rainy period, it may be suitable for areas with well distributed rainfall.