Population Growth Characteristics of Super Hybrid Rice Yangliangyou 6 with Different Transplanting Densities

The group growth and development characteristics of super rice,Yangliangyou 6,was studied under different planting densities with Shanyou 63 as a control.Chlorophyll content was evaluated with SPAD determinator,photosynthetic rate,transpiration rate and stomatal conductance were surveyed with CID porosity apparatus,and yield traits,dry matter,and basic agronomic traits were measured by conventional methods.The tillering capability of Yangliangyou 6 was medium to low.Before booting,Yangliangyou 6 showed rising in leaf area index as the transplanting density was increased.However,leaf area index stayed stable when the transplanting density reached 3.00 ×105 holes in 1 hm2.After heading,the photosynthetic rate,transpiration rate and stomatal conductance of Yangliangyou 6 declined,the slowest declining speeds at the transplanting density of 3.00 ×105 holes in 1 hm2.The transportation of photosythetic product to the seed enhanced,with the highest transportation at the transplanting density of 3.00 ×105 holes in 1 hm2.In different planting density trials,Yangliangyou 6 presented the largest number of total spikelets,the highest seed setting rate,stable 1 000-grain weight and highest yield level under 3.00 ×105 holes in 1 hm2 condition.The results indicates that an appropriate transplanting density is effective to improve yield potential for Yangliangyou 6.