Effect of Spacing on Seed Yield of Indigenous Rangeland and Forage Grass Species Grown under Drip Irrigation

Two indigenous rangeland forage species, Cenchrus ciliaris and Coelachyrum piercei, were investigated for their response to varying inter-row (50 and 100-cm) and inter plant spacing (25, 50 and 100-cm) under drip irrigation along with the perennial popular forage, Rhodes grass (Chloris gayana). Expression of traits, such as plant stand, plant height, number of tillers, number of panicles and seed yield, differed under varying inter-row and inter-plant spacing in different harvests. The grass species produced higher seed yield due to less interplant competition under wider (100-cm) than under narrow row (50-cm) spacing. Chloris gayana produced highest mean seed yield in wider inter-plant spacing (100-cm) under both inter-row spacings, viz. 100-cm (488 kg/ha) and 50-cm (449 kg/ha), followed by Cenchrus ciliaris (449 kg/ha under 100-cm and 377 kg/ha under 50-cm row spacing) and Coelachyrum piercei (274 kg/ha under 100-cm and 210 kg/ha under 50-cm row spacing). In respect of seed quality for samples harvested selectively or in bulk, the three grasses showed very low germination when tested immediately (1-2 weeks) after harvest, not only for bulk seed (0 to 1.5%) but also for selected seed (0.8% to 2.8%). Mean germination of grass species recorded after 12 months of harvests was significantly greater (53 %) than that recorded after 5 months (34 %) of harvests. Of the three grass species, Cenchrus ciliaris recorded significantly (p<0.01) highest germination % (50 %) followed by Chloris gayana (41 %) and Coelachyrum piercei (39 %). Selected seeds had significantly (p<0.01) higher germination (53 %) than bulk seeds (33 %).Keywords: