Effects Of Plant Configuration On The Source-Sink Characteristics And Yield Of Super Hybrid Rice

Reasonable plant configuration is an important basis for obtaining high and super high yield of rice.Clarifying the effects of plant configuration on yield and the source and sink characteristics and their relationship in yield formation process of super hybrid rice can provide support for further inreasing the yield per unit area of rice.Taking two super hybrid rice varieties（large panicle variety"Sanyouyihao"and medium panicle variety"Tianyouhuazhan"）as materials,under the condition of consistent basic seedlings in the field,the effects of different plant row spacing（equal row plant spacing,T1;wide row and narrow plant,T2）and different planting methods（two seedlings per hill,P1;one seedling per hill,P2;two separated seedlings per hill,P3）on the yield of super hybrid rice were compared,and the ways of high yield formation of T2P3 treatment was analyzed from the perspective of source sink relationship with T1P1 treatment as the control.The main results are as follows:（1）Compared with T1,the tillering rate of T2 treatment was slow at the initial stage of tillering,but its continuous tillering time was longer,and the number of tillers decreased less in the late stage,so the number of effective panicles was more and the yield was significantly increased.The combination of P3 and T2 could further improve the panicle rate,effective panicle number and yield,but it had no advantage in cooperation with T1.The number of effective panicles and yield of T2P3 treatment were the highest in both varieties,but their ways of increasing panicles were different,Sanyouyihao increased number of medium and large panicles,while Tianyouhuazhan increased number of medium and small panicles.（2）Plant configuration affected the leaf area index（LAI）and canopy leaf morphology of Super Hybried rice.In the middle and early growth stage,T1 and P2 had larger LAI,but it decreased faster.In the middle and late growth stage,the LAI of T2 and P3 was larger.At the mid-filling stage,the LAI of T2P3 was the largest,which was 27.63%-28.72%higher than that of control.The length,width and area of the upper three leaves showed that T2 was greater than T1,P3 was greater than P1 and P2.Compared with the control,the length,width and area of the upper three leaves in T2P3 treatment increased significantly,and area of the upper three leaves of Sanyouyihao and Tianyouhuazhan increased by 16.28%-17.77%and23.94%-27.52%,respectively.（3）Plant configuration had little effect on Leaf SPAD value,net photosynthetic rate and intercellular CO₂concentration,but P3 treatment significantly increased transpiration rate and decreased stomatal conductance,total water vapor conductance and total CO₂conductance.Compared with the control,transpiration rate increased by 24.59%-37.84%,the stomatal conductance decreased by 17.74%-33.81%,the total water vapor conductance decreased by 16.05%-30.12%,and the total CO₂conductance decreased by 16.28%-30.58%in T2P3 treatment of two varieties.（4）Compared with T1,T2 treatment had no advantage of improving population dry matter from tillering stage to booting stage,but the advantage was obvious after full heading.The total biomass and panicle dry weight of T2P2 and T2P3 treatment were the highest in the two varieties,and the total biomass of Sanyouyhao and Tianyouhuazhan in T2P3treatment increased by 23.45%and 22.12%,respectively compared with the control.（5）Plant configuration affected the distribution density of single stem and sheath mass at full heading stage.Compared with T1 treatment,T2 treatment significantly increased the number and proportion of stem and sheath with medium weight,and P2 and P3 treatment slightly reduced the number of stem and sheath with high weight compared with P1 treatment,but they improved the population uniformity.T2 combined with P2 and P3 treatment could significantly improve the total weight of stem and sheath at full heading stage,and the weight of stem and sheath of T2P3 treatment of Sanyouyihao and Tianyouhuazhan was 9.53%and 17.99%higher than that of the control respectively.（6）Plant configuration affected the distribution density of number of spikelets per spike at full heading stage.The number and proportion of medium spikelets in T2 treatment were significantly higher than those in T1 treatment.P2 and P3 treatments could increase the total amount of spikelets under wide row spacing,but the advantage was not obvious under equal row spacing.The total amount of spikelets in T2P3 treatment of Sanyouyihao and Tianyouhuazhan at full heading stage increased by 21.65%and 20.89%respectively compared with the control.（7）There was a highly linear correlation between stem weight and spikelet amount.Cultivating high weigt stems was the key to improve the total spikelet amount.Compared with the control,the tillering rate of T2P3 treatment was reasonable,the panicle rate was significantly improved,and the flowering efficiency of stem and sheath was higher.The flowering efficiency of Sanyouyihao and Tianyouhuazhan were 11.23%and 2.49%higher than the control,respectively.（8）Correlation analysis showed that the yield of two varieties was significantly positively correlated with the total number of spikelets and LAI at full heading stage,positively correlated with the output rate of stem and sheath material,while it had little correlation with ratio of total grain to leaf and ratio of filled grain to leaf at full heading stage and mid-filling stage.Plant configuration mainly improved the yield by increasing the total number of spikelets,Lai at full heading stage and the output rate of stem and sheath materials.In conclusion,plant configuration significantly affects the yield and source sink characteristics of Super Hybried rice.One seedling per hill and two separated seedlings per hill have the effect of increasing source,while wide row and narrow plant can increase source and sink simultaneously.Wide row and narrow plant combined with two separated seedlings per hill（T2P3）has the best effect on increasing source and sink,which can make super hybrid rice establish the coordination relationship of source and sink at a higher level,so as to realize yield increasing.