INTERACTIVE EFFECTS OF PLANTING SEASON, MULCHING AND VARIETY SELECTION ON GROWTH, DEVELOPMENT AND YIELD OF WHITE YAM IN THE TROPICAL WET-AND «¤??DRY CLIMATE OF NIGERIA

The effects of planting season, mulching and variety selection on growth, development and yield of white yam were evaluated in two trials in 2007 and 2008 cropping seasons. Mulching and planting season significantly increased tuber yield and also increased the expression of yield components and vegetative characters. The yield of Efuru and Ise-osi were more than that of Oneyere, particularly on mulched plots during the dry season planting. Early season plantingª¤? significantly (P < 0.05) influenced emergence rate, phenological growth and tuber yield. Irrespective of mulching materials, it was found that mulching significantly (P< 0.05) increased tuber yield by about 6-8 tonnes ha-1 season-1 over the unmulched. Furthermore, grass mulch had tuber yield of about 4-6 tonnes ha-1 season-1 greater than the polythene mulch and the unmulched plots. Growing yam variety that synchronizes the crop growth cycle with effective water availability during the early planting season with proper mulching is therefore recommended.ª¤