| Summary: | Seed filling and yield of soybean under water and radiation deficits were investigated during 2011 and 2012. Treatments were irrigations (I1, I2, I3 and I4 for irrigation after 60, 90, 120 and 150 mm evaporation from class A pan, respectively) in main plots and light interceptions (L1: 100 %, L2: 65 % and L3: 25 % sunlight) in sub-plots. Seeds per plant under I1 and I2 decreased, but under I3 and I4 increasedas a result of radiation deficit. Maximum seed weight and seed filling duration of plants under 25 % light interception (L3) were higher than those under full sunlight (L1) and 65 % light interception (L2). In contrast, plants under full sunlight had the highest seed filling rate, particularly under water stress. Seed filling duration under severe light deficit (L3) was about 9 days longer than that under full sunlight (L1), leading to 15.8 % enhancement in maximum seed weight. Decreasing seed yield of soybean under well watering and mild water stress and improving it under moderate and severe water deficit due to low solar radiation are directly related with changes in seed filling duration and consequently in seed weight and number of seeds per plant under these conditions.
|
|---|