Studies On Population-Quality Indices And Its Relationships And Yield Of High Yield Wheat

This paper systemically studied the Population-Quality indices, physiological characteristic, yield and it's three components and the relationships among them, with 2 new cultivars bred by Henan Agricultural university in different sowing times and sowing densities and Yumai 49,Yumai 18 (suitable density and date ) treatments under field conditions in 2002-2003 and 2003-2004 growing seasons.The main results were as follows:1. Population-Quality indices reflect better or worse quality of population during wheat high-yield cultivation. The results indicated that increasing the percentage of main stems and tillers while stabling suitable panicles was the important and easily grasped indication of Population-Quality. The biggest, optimum LAI in booting and keeping area of green leaves longer time played very important roles in the dynamic change in growing and development period of LAI. High or low harvest dry matter, to certain extant, decided in dry matter accumulation from heading to harvest, and the basic factor for high-yield results from increasing dry matter accumulation after heading. Increasing grain-leaf area ratio based on suitable LAI can enhance level-population-quality, furthermore, boosting yield.2. As a very important index, the level of CAP can reflect the suitable degree of LAI, is closely related to LAI. In this experiment, the CAP generally appeared as a single-peaked curve and the peak value reached at anthesis. The earlier sowing treatments ascend rapidly and appeared advantages in the early growth period than the later ones. But in the middle and late growth period, the differences of CAP among the sowing date treatments appeared insignificantly. CAP of the highest density treatments appeared higher than other density treatments while declined rapidly at the last stage. Except for the last stage of filling, CAP of the lowest density treatments showed disadvantages at other stages.3. Fitting sowing date and density did benefit to strong and weak grain fill at the same filling speed, reduce the ratio of shrunken grains, increase kernel's weight based on the data of trends of kernel's weight and filling speed of the different treatments. Studies on the content dynamic change of four hormones showed that ZR contentwould be decreased if sowing date arranged too early or too late. But to sowing density, there is no apparent discrepancy in different treatments. IAA content showed an almost unanimous trend among different sowing date and sowing density treatments, yet there is a higher IAA content in fitting sowing date and low density treatment than other treatments. ABA content Change in different sowing date treatments showed distinctly in strong grain, that is to say, the ABA content peak of the earliest sowing date treatment appeared earlier while the latest sowing date treatment appeared later than other treatments and the ABA content peak in fitting sowing date treatment were accord with the peak of filling speed. To different sowing date treatments, the content of GA3 in strong grain appeared evidently higher than in weak grain. On the other hand, there were different sequences among different sowing density treatment, furthermore, the peak content of ABA in lower density appeared earlier than in higher density treatment.4. Effects of different sowing density treatments on chl content became apparent at late filling stage and car content showed a little higher in fitting density than in other density treatments of the both cultivars. C/N in stem and grain of Guomai l's 300>0) before booting stage, augment of CAP along with LAI. From booting to early filling stage, the correlation between CAP and LAI appeared quadratic equation: Y=a+b*X+c*X2. From every curve we can see that there was one peak appeared in Guomai's treatments and the suitable LAI showed apparently from booting to early filling stage. But to Yunong 9901, the trend took on CAP increasing accompany with LAI under density scope of this experiment. To additional, the results of correlations between hormone and grain weight, speed of filling showed that GA3 had achieved positively significant or very significant level and effects of the ratio of GA3 to the other three hormones on grain weight and speed of filling of earlier sowing, fitting density treatment achieved positively significant or very significant level too.Based on the above results, population-quality indices have a dynamic changing process and the last high yield of wheat were obstained by population in line with single, nutrition growing harmony with procreation growing. During the process of population control, the first step is that we should make certain suitable sowing date and fitting seedlings according to the cultivar's characteristic to assure that population had a suitable development jumping-off point. The second step is that we should adopt reasonable control methods to assure that population developing in suitable track. We should grasped perfectly extent of the maxim LAI and control the decline ratio of high efficiently LAI at the third step. At last, increasing population dry matter especially for photosynthates transporting and accumulating after heading should be increased to avoid premature senility or later mature. Guomai 1 has higher tillering ability and semi-winter while Yunong 9901 has general tillering ability and weak spring...