Abstract
The experiment was carried out under the condition combining the shading periods (20days, 40 days, 60 days after emergence) and the shading grades (shade 1; 60% of the solar radiation, shade 2; 40% of that, shade 3; 25% of that). The results obtained were as follows. 1. As the shading period became longer and the shading grade higher, not only the early growth during the shading treatment but also the late growth after that was inhibited more remarkably. 2. The first and the last day of flowering, especialy the latter, were delayed with the prolongation of the shading period and with the increase in the shading grade, resulting in the prolongation of the flowering period. The development and growth of the vegetative and the reproductive branches were suppressed by the shading, and consequently, the total number of flowers decreased. 3. The shading at the early growth stage inhibited the fructification of the early flowers, and reduced the number of the mature pods per plant and the shelling percentage, resulting in the decrease in the yield. 4. It was considered that the critical light condition at the early growth stage of peanut plants to recover the subsequent growth and to gain the yield apporoximately similar to that of the plants grown under the natural light condition was 60% of the solar radiation during 60 days after emergence, 40% during 40 days, or 25% during 20 days.
