PRODUCTIVITY OF DIFFERENT SEED SIZE OF PE ANUT CANOPY AS INFLUENCED BY PLANTING DENSITY

In the fall crop of 1991 and the spring crop of 1992, two peanut culti vars differing in seed size were seeded with different intra-row spaci ngs to determine the effect of plant density on the development and pr oductivity of peanut canopy. Generally, the pod yield and harvest inde x of both cultivars in the spring crop was higher than those in the fa ll crop. Pod and kernel yield of Tainan S.9 (small seed type cultivar) per unit land increased with increasing plant density in fall crop. b ut was not changed when plant density was increased in the spring crop , Pod and kernel yield of Tainan 11 (large seed type cultivar) per uni t land was not increased with increasing plant density in the spring a nd the fall crop. In both cultivars. early canopy development was hast ened and maximum crop growth rate was reached earlier when plant densi ty increased. Leaf area index (LAI) of both cultivars at the stage of maximum CGR. at the stage of maximum LAI. and the stage of maximum PFR increased with increasing plant density. But, the relationship of ULR and plant density of two cultivars was different. Pre-podding assimil ates which stored in vegetative organs had some contributions to final pod yield. The proportion of pre-podding assimilates translocated to pod in Tainan 11 (large seed type cultivar) was higher when plant dens ity was increased. Contradictory. the proportion of pre-podding assimi lates translocated to pod in Tainan S.9 (small seed type cultivar) was not chaneged when plant density was increased. Current assimilates fi xed during pod filling stage of Tainan 11 contributed 87-95% to final pod yield in both the spring and the fall seasons. In Tainan S. 9; 84- 92% and 70-80% of current assimilates fixed during pod filling stage c ontributed to the final pod yield in the spring and the fall crop, res pectively.