The Research On The Grain Filling Character Of Wheat Cultivars Of Different Ecological Types

To realize the change of filling characteristics of different ecological types sping wheat,eighty-nine spring wheat cultivars were selected to be used to study their grain filling characters under the north-west oasis ecological condition, the main results are as follows:1 .During the course of wheat grain filling,the process of the increase of different types grain's weight (that is,the process of grain filling) presents a shape of "S",which means the initial period was slow,the middle period was fast and the late period of filling tended stableness,and the growth curve of grain dry weitht could be simutated with Logistic equation.The correlation coefficient was above 0.9977 and regression equation was at significance.There was difference among the contribution rate to grain in three stages, which mainly manifested as the contribution rate to grain in middle period > that of initial period > that of late period of filling. The changes of grain filling rate of different types had a single-peak curve, which was the same as that of grain weight.2.At each stage of grain filling processes,the thousand kernel weight of coarsely grain was well over 57.8g,was 5.78g and 14.33g higher than that of medium grain and small grain respectively.The contribution rate to grain in different grain weight types were of significant difference at different stage of grain filling processes. In initial period,the contribution rate to grain of coarsely grain was lower than that of medium and small grain;In middle period,the contribution rate to grain presents: medium grain type> small grain type >coarsely grain type;In the late period of filling,the contribution to grain of coarsely grain was the highest. The average rate of grain filling(R),the whole period of grain filling (T),the maximum rate of grain filling (R_max),the time of maximum rate of grain filling (T_max) of coarsely grain types were higher than that of medium and small grain types;In initial and middle period,the rate of grain filling of coarsely grain type was faster than that of medium and small grain types,however,small grain types has the highest grain filling rate in the late period. In addition,the days of grain filling of slow growth period on coarsely grain type lasted longer and the time of maximum rate of grain filling was delayed to 19d after anthesis.The correlation analysis showed that the whole period of grain filling and the average rate of grain filling significantly affected coarsely and small grain weight,the influencing of T was more obvious than R for coarsely type grain weight, while the influencing of R was more obvious than T for small type;The medium type grain weight depended mainly on R.On further analysis,the grain weight was extremely significantly positively correlated with the rate of grain filling of gradual growth period (R1),was significantly or extremely significantly positively correlated with the days of grain filling of fast growth period (T2).3. At each stage of grain filling processes,the thousand kernel weight of large-panicle type was well over 59.7g,was 8.20g and 17.65g higher than that of medium-panicle and small-panicle types respectively.The contribution rate to grain in different spike types were of significant difference at different stage of grain filling processes. In initial period,the contribution rate to grain of large-panicle type was lower than that of medium and small-panicle types;In middle period,small-panicle type > medium-panicle type > large-panicle type;In the late period of filling,large-panicle type was the highest. R,T,Rmax of large-panicle type were higher than that of medium and small-panicle types. In initial and middle period, the rate of grain filling of large-panicle type were faster than that of medium and small-panicle types,however, small-panicle type has the highest grain filling rate in the late period. In addition, Tmax on different spike types were basically identical to 20d after anthesis.The correlation analysis showed that the whole period of grain filling and the average rate of grain filling significantly affected large-panicle and medium-panicle types,and the influencing of T was more obvious than R,however,grain weight of the medium-panicle type depended mainly on R.On further analysis, the grain weight of large-panicle types was extremely significantly positively correlated with the days of grain filling of slow growth period (T3),while that of small-panicle types depended mainly on the days of grain filling of gradual period (T1) and medium-panicle type was extremely significantly positively correlated with second parameters expect the rate of grain filling of slow growth period (R3). Therefor,Prolonging the days of grain filling of gradual and slow growth period (T1,T3) was a main way to increase the grain weight.4.At each stage of grain filling processes,the thousand kernel weight of high height type was well over 52.6g,there were no significant differences among the three types.The contribution rate to grain in those types were of significant difference at different stage of grain filling processes. In initial period,the contribution rate to grain of medium height type was higher than that of low and high height types;In middle period,low height type > medium height type > high height type;In the late period, high height type was the highest.R,T,Tmax of high height type were higher than that of medium and low height types. In initial and late period, the rate of grain filling of high height type were faster than that of medium and low height types;In middle period, medium height type has the highest grain filling rate. In addition, T_max of different height types were basically identical to 19d after anthesis.The correlation analysis showed that the whole period of grain filling and the average rate of grain filling significantly affected different height types,and the influencing of T was more obvious than R. On further analysis,the grain weight of different height types was extremely significantly positively correlated with the rate of grain filling of fast growth period (R2), R1, T2 and T3.5.At each stage of grain filling processes,the thousand kernel weight of late-ripening types was well over 57.8g, was 5.94g and 14.1g higher than that of middle-ripening and early-ripening types respectively.The contribution rate to grain in different maturity types were of significant difference at different stages of grain filling processes. In initial period,the contribution rate to grain of middle ripening type was higher than that of early-ripening and late-ripening types;In middle period,early-ripening type > late-ripening type > middle-ripening type;In the late period, late-ripening type was the highest. T,R_max of late-ripening type were higher than that of middle-ripening and early-ripening types.In initial and medium period,the rate of grain filling of late-ripening type were faster than that of middle-ripening and early-ripening types;In late period, early-ripening type has the highest grain filling rate .In addition,T3 of late-ripening type lasted longer and Tmax of different height types were basically identical to 19d after anthesis.The correlation analysis showed that T and R significantly affected late-ripening type,and the influencing of T was more obvious than R;Grain weight of the middle-ripening and early-ripening types depended mainly on R. On further analysis,the grain weight of late-ripening type depended mainly on R1,R3; while that of middle-ripening type was extremely significantly positively correlated with T1,R1,R2,R3;Early-ripening type was extremely significantly positively correlated with Rl,Therefor,increasing R1 was a main way to increase the grain weight.6.The relations between grain dry weight and their parameters was analyzed by correlation analysis,the analysis showed that the influencing of T was more obvious than R.On further analysis,grain dry weight and their parameters showing a very significant correlation. The linear regression analysis showed the main factors affecting grain dry weight were R2 and T3.