Influence of plant population and sett size on biomass accumulation and quality of white yam (Dioscorea rotundata) intercropped in coconut (Cocos nucifera) gardens

A field experiment was conducted during 1998–99 and 1999–2000 (May-February) at College of Agriculture, Vellayani, Thiruvananthapuram, to investigate the effects of plant population and sett size on biomass accumulation and quality in white yam (Dioscorea rotundata Poir.) intercropped with coconut (Cocos nucifera L). Heaviest sett (300 g) planted at the widest spacing (90 cm x 90 cm) promoted the canopy growth. Tuber dry biomass production and total plant dry biomass production were highest in the closest spacing, 60 cm x 60 cm, that accommodated 20, 000 plants/ha. Efficient allocation of photo-assimilates for storage in tuber was favoured by the widest spacing, 90 cm x 90 cm, resulting in highest mean tuber weight and harvest index. Total biomass production, biomass accumulation in tubers as well as its partitioning ratio to tubers were notably higher with 300 g setts. Wider spacing (90 cm x 90 cm) also produced better quality tubers by accumulating more starch in tubers, while sett size did not alter tuber quality.