Comparison Studies On The Productivity Of Different Nodes Of Main Stem In Rice

The rice population are made up of individuals,whereas every individual rice plant are made up of main stem and tillers of different nodes on it.The rice productivity is under the condition of population,and the productivity of every individual rice is determined by the yield of different nodes of main stem.Since the population is formed by individuals,basis for regulating the population structure can be made only when characteristics of the quantity changes about the productivity of different nodes of individual plant are clarified.Recently,researches about the productivity of rice appear to be turning to the nodes on the basis of studies on individual plant,and discussions about the productivity of different nodes have been made from different viewpoints. Precisely analyzing the productivity of different nodes and clarifying the factors of yield about different nodes can help exploit the productivity of different nodes with high efficient and provide support of skill for precise cultivation and quality population production of rice.Experiment 1 was performed under potted individuals,Shanyou63 as the test material in the spring.Plants in the experiment were controlled artificially by removal of some tillering nodes on the main stem,forming node combinations of different quantities and different positions(lower position,middle position and upper position on the main stem),doing research into productivity characteristics of each node of main stem.The results indicated:1)the Number of spikelets is interrelated significantly with the effective panicles,leaf area,biomass in rice heading date,larger number of panicles,larger leaf area and higher biomass showing larger number of spikelets, thereby increasing grains per spike and economic yield;2)With node position shifting bighter, effective panicles,leaf area and biomass of each node in rice heading date decreases gradually, indicating that lower nodes are the predominant nodes that produce effective panicles,leaf area and biomass;3)In the ripe date,economic yield of each node decreases from the lower nodes to the upper nodes in each treatment,though the number of effective panicles of the plants that had the lower tillering nodes removed is smaller,grain number per spike of middle and upper nodes increases clearly and the node productivity and the eonomic yield per plant is not lower than the CK either,for instance the treatment with tillering nodes from 2^ndto 6^thshows the highest economic yield,and other treatments with nodes 2^nd,3^rdand 6^thto 8^th,with nodes from 4^thto 8^th,and with nodes from 5^thto 7^thalso indicate relatively higher economic yield though with relatively less tillering nodes;4)This experiment also indicates that competition exists in the internal nodes and among different nodes on the main stem.Eliminating or decreasing these competition can help increase the grain number per spike.For instance,the treatment with the nodes from 2^ndto 6^th,from 4^thto 8^thand from 6^thto 10^theach has five tillering nodes,but the one with tillering nodes from 2^ndto 6^thhas the largest number of effective panicles and the least number of grain number per spike for the strongest competition in the internal nodes.The treatments with tillering nodes from 2^ndto 6^th,from 2^ndto 4^th,from 2^ndto 3^rdand only 2^ndshow decreasing tillering nodes as well as decreasing competition among nodes gradually,while the treatment with only 2^nd node that tillers has the largest grain number per spike on average.This study has provided new theory supports for further improving quality of the population under the condition of super-high yield cultivation.Experiment2 was performed in the field,scarce planting(100cm×50cm)with the Shanyou63 used as the materials,aimed to exploit the economic yield of the main stem and the primary(P),second(S),tertiary(T)tillers of the nodes from 2^ndto 9^thon the main stem.Each treatment consisted of the main stem and one,tow or four specific nodes classified into lower-position nodes(L),middle-position nodes(M)and upper-position nodes(U)on the main stem.Each plant in the same treatment was controlled artificiallywith the same number of panicles 16 and the same number and order of P,S and T tillers at the specific nodes.The results were as following:1)in the treatments with the same number of specific nodes on the main stem,the average number of total leaves and panicle weight on the main stem increase as the position ascends and increase as the number of specific nodes decreases between the treatments with different number of specific nodes on the main stem.2)in the treatments with same number of the specific nodes,the average panicle weight of P is U＞M＞L;the average panicle weight of S is M＞U＞L in the treatments with one specific node,U＞M＞L in the treatments with tow or four specific nodes;the average panicle weight of T is M＞U＞L in the treatments with one specific node,U＞L＞M in the treatments with tow specific nodes,U＞M＞Lin the treatments with tow specific nodes.3)the average panicle weight of a whole plant is M＞U＞L in the treatments with one or tow specific nodes,U＞M＞L with four specific nodes.From 1)to 3)show that the economic yield of tillers of L is not higher than the tillers of M or U,though the tillers of L emerge earlier and have more leaves than the tillers of M and U.4)hierarchy(account for occupy percentage of mai spike)of the average panicle weight of tillers increase as the positions of specific nodes shift bighter while the trend becomes slow as the number of specific nodes increases.5)the number of main stem spikelets is closely correlated with leaf blade elongation from the leaf sheath of the main stem,the same with the primary tillers;the relationship between the average rate of leaf blade elongation from the leaf sheath of the main stem and the average panicle weight of tillers show differences at different node position,generally presenting a parabola,except when there is only one tillering node on the main stem,the average panicle weight of tillers decreases rapidly from M to U nodes.Summing up the study results above indicates that in order to compare the productivity of lower,middle and upper nodes on the main stem,number of the tillering nodes and the makeup of tillers must be the same and without this premise,each conclusion is unilateral.At the last,this paper has made further discussions about the higher yield of the upper nodes from the characteristics of ecology,physiology,botany and development under the individual planting.