Effects of different sizes of planting material on the stablishment and precocity of durian

The growth and reproductive performance of different sizes of durian planting material (0.64-2.53 cm calliper size) aged between 6 and 30 months old was studied. The suitable size of planting material for improving durian precocity and thus reducing the juvenile phase was determined. The trial was carried out at MARDI Research Station, Jerangau in 1992 using clones, D24 and D99. Growth was monitored and data recorded were the girth size increment, flowering and fruit yield, for a period of 6 years after field establishment. Both D24 and D99 had vigorous growth, but D99 had significantly better survival rate after one year of planting and higher yield than D24 during reproductive phase. Initial tree calliper size had a negative influence on tree survival in durian. As the tree calliper size increased, the rate of tree survival was reduced. First flowering was detected 3 years after field planting in some of the trees but without fruit set. After 5 years in the field, all trees flowered and bore fruits. Results indicated that 2.0 cm planting materials had the highest growth rate and tree vigour, and was the optimum size for improving precocity. It also significantly produced highest mean fruit number (23 fruits).