抄録
Two azuki bean cultivars, Takarashozu (medium) and Akatsukidainagon (late), were grown in the equidistant square pattern at five population densities, and dry matter accumulation in the plant communities were analyzed. The main results obtained were summarized as follows: 1. The maximum dry matter production was not differed in densities over 16 pls./m2, irrespectively of variety, and was about 620 g/m2. 2. With increase in population density, dry weight of branches decreased remarkably and disappeared at the highest density. 3. CGR and LAI during growing season shifted higher with higher densities for Takarashozu, but were relatively constant for density for Akatsukidainagon. NAR dropped temporarily at the late July in the higher densities for Akatsukidainagon. 4. Relative light intensity at the bottom of the canopy was associated with LAI. The regression value (Ks) differed between varieties, and the LAI required for 95% light interception was 5.0 and 3.3 for Takarashozu and Akatsukidainagon, respectively. 5. The decrease in NAR with the increase of LAI initiated from LAI about 0.3. 6. The estimated values of LAIopt. and CGRmax. varied with varieties and stages. The maximum values of LAIopt. and CGRmax. were 4.1 and 14.7 g/m2/day, and 3.7 and 16.7 g/m2/day for Takarashozu and Akatsukidainagon, respectively. 7. The efficiency of dry matter accumulation per unit photosynthetically-active radiation (PAR) intercepted (EPAR, dry weight mg/kcal.) attained to the maximum near the maximum leaf area stage, then decreased. 8. Significant simple correlation coefficients were recognized between LAIopt., CGRmax. and EPAR (mean value of each stage), suggesting that the variations in LAIopt. and CGRmax. were partially due to photosynthetic activity changing with growth.
