Study On Effects Of Integrative Plant-Grain Choice Of Maize Inbred Lines

Variety retrogression is a universal phenomenon in agricultural production, so improving crop varieties by using proper technical means could delay the degradation of its species and prolong productive life of excellent varieties effectively. In this experiment, taking the Zheng Dan958 and its parents which extension area was the largest of the current promotion of maize varieties as material , through a multi-generation lines for gifted and excellent choice of grain and position on the basis of superior plant,the effect of growth and yield of hybrid posterity hybrid posterity after integrative plant-grain choice were studied by laboratory and field experiment . The main results were as follows:1.Seed vigor and seedling quality were enhanced after integrative plant-grain choice, and MS showed best ,the germination rate, the germination potential and the activity index of MS were more than that of CK by 11.67,4.02,1.37 percentage point, respectively. On seed vigor and seedling quality ,TS was a little better than CK, but the difference was not significant, all of SM,MS,LS were better than CK, especially MS; through the comparison of four treatments, TS was worse than MS, but MS and LS were better than SM.2. Integrative plant-grain choice improved the growth of hybrid posterity, especially matter accumulation, the effect on agronomic characters was not significant, the dry matter accumulation of SM was biggest, but the difference between MS and LS was not significant. The height and ear height of four treatments were higher more than CK only in the Silking period, and the difference was significant, but the difference on stem diameter and area of green leaf was not significant; specific leaf weight and dry matter accumulation of four treatments were more than that of CK, but the difference between US and CK was not significant in part of periods. The differences of the height ,ear height, stem diameter and area of green leaf were not significant among four treatments, the leaf weight ,injuried flow of fruit stem and dry matter accumulation of SU were lower than that of SM, SC and SL were higher than SM, and the differences were both significant.3. The choice of individual plant and grain position enhanced the chlorophyll content and the ability of anti-ageing, and was beneficial to photosynthesis, besides the photosynthetic capacity of SC and SL was move strong. The chlorophyll content and SOD activity of SM were higher than that of CK, but the difference among SM , SU and CK was not significant, however the difference both SC and SL with CK was significant, Pn,En,ETR,Fv/Fm,ФPSⅡ,qP of SM were higher than that of CK, the difference between SU and CK was not significant, the difference among SM,SC, SL and CK was significant, while MDA and NPQ of SM were lower than that of CK, the difference between SU and CK was not significant, and the difference among SM,SC, SL and CK was significant ;the chlorophyll content ,SOD activity, Pn,En,ETR,Fv/Fm,ФPSⅡand qP of SU were less than that of SM, and SC,SL were more than SM, however MDA and NPQ of SU were higher than that of SM,but SC,SL were lower than SM.4.After the choice of individual plant and grain position, the incidence of diseased leaves decreased, but the disease resistance improved, and the ability of anti-ageing enhanced; the index of gray leaf spot disease of SL was the least, and the index of rust diseased leaves of SC was the least. The incidence, index and epidemic degree of the two disease decreased comparing with CK after choice ;the disease incidence of SU was higher than that of SM, and the disease incidence of SC and SL were lower than that of SM.5. The yield-increasing effect was significant after integrative plant-grain choice, and the yield of SC was the most: 10438.62kg/hm~2, then SL, but the difference between SC and SL was not significant. Compared with CK, the percent of increasing yield of SM,SU,SC and SL was5.12%,4.33%,15.77%,16.4% ,respectively, the difference among SM, SC,SL and CK reached significant level; the yield of SU was less than that of SM by 0.75%, the difference was not significant,while the yield of SM was lower than that of SC and SL by 10.7%,10.13%,respectively, the difference was not significant yet.6. After integrative plant-grain choice, all of the content of lysine, crude fat, crude protein and starch increased, the quality of SL was best.Compared with CK, the content of lysine, crude fat, crude protein and starch of hybrid posterity of SM, SC and SL were more than that of CK, and the difference were significant, the crude protein content of SU was lower than that of CK, the difference reached significant level; the starch content of SU exceeded that of SM, and other indices of SU were all lower than SM, however all indices of SC and SL were more than that of SM.