Effects of Shading at Different Growth Stages on Different Traits and Yield of Soybean

Abstract

Intercropping and relay-intercropping are important technologies to improve land utilization rate and crop yield,but their yields are limited by shading,which is different for intercropped soybean and relay-intercropped soybean at different growth stages.To clear the effect of shading at different growth stages on morphology and yield of soybean,we treated Guixia 2,Nandou 12,Nandongkang 22,E61,and C103 with the 50% transmittance shading net using the natural light as control.The results showed that effects of shading on different morphological characters were different at different growth stages,showing a significant influence on length of main stem and main stem length/stem diameter during the early growth period(VER1 and VER2).Compared with control,the main stem length and main stem length/stem diameter were increased by 45.75% and 93.64%,respectively.Shading had significant influence on the number of branches and the height of lowest pod at the late growth stage(R1R8 and R2R8).Compared with control,the number of branches was decreased by 29.97% and the height of lowest pod was increased by 28.59%.The effects of shading on yield of cultivars with different growth periods were different,the cultivars with R/V below 1.4 was affected significantly by the early growth period shading,the cultivars with R/V equal to or greater than 1.5 was easily affected by the late growth stage shading.Results of correlation analysis and path analysis showed main stem length,first internode length,branch height,stem length/stem diameter and stem length/branch number were negatively correlated with yield per plant significantly,branch number was positively and significantly correlated with yield per plant,main stem length/stem diameter and main stem length/branch number could be key indices for yield per plant.