Study On The YS-Type Thermo-Sensitive Male-Sterile Wheat Line In Seed Production

To solve the question of hybrid wheat seed production immature technology, lower yield and higher cost, this paper used a series of YS-type thermo-sensitive male-sterile wheat line which were given by the hybrid wheat two-line topic-based group of Northwest A & F university to study the effect of two kinds of hormone on plant character, flower character, outcrossing rate and the hybrid seed yield of the male-sterile line particularly; to research the effect of plant height difference to the outcrossing rate and yield in the hybrid wheat conventional production; to analyse the effect of plant height and florescence difference to the outcrossing rate in the new system of producing hybrid wheat seed by mixing male sterile line and restorer line. The article provided the reliable model for the hybrid wheat breeding, thus can cause its wide-spread application. The main results were as follows:1. The hormone had certain influence to the wheat period of growth. MET in seed dressing which was 75~120g/hm2 can postpone the seedling stage, the heading period and florescence 2days, but the higher concentrations which was 135~150g/hm2 can defer seedling stage 3days, heading period 4days and florescence 3days separately. On the base of MET in seed dressing, it had no influence to growth period of main treatment on the highly concentrated (135~150g/hm2), but it may lead to ahead of time 1day to other treatment such as heading perid and florescence after spurting GA3 in the booting stage.The suitable concentration of MET in seed dressing can reduce plant height 1.43%~5.65%, particularly the length of three bottom internodes, increase the ears 24.88~66.51%, promote the stigma length 2.64%~6.16%, improve the stigma exsertion rate 0.88%~4.57% and enhance the angle of grain husk 6.93%~14.35% finally. Through the experiment of stigma viability, MET in seed dressing can also make the peak of stigma viability 3~4days in advance, and can obviously enhance the outcrossing rate, but not lengthen the duration times.In short, 135g/hm2 was the best concentration for MET in seed dressing, furthermore, lead the outcrossing rate to 35.63% and the hybrid seed production over 2000kg/hm2, however, further applying GA3 can not raise the hybrid seed yield. Through MET in seed dressing, it can optimize wheat group and outcrossing characteristic of sterile line, thus can raise the hybrid seed yield.2. According to the different materials in the years of 2005~2006 and 2006~2007, we drawed the similar conclusion: difference of plant height had tremendous influence to the outcrossing rate and yield in the hybrid wheat conventional production, and it achieved the extremely remarkable relevance after the correlation analysis. Under the condition of row-ratio of male vs female was 3:8 and from 5cm to 45cm of plant height difference, the outcrossing rate and yield increased gradually, and it shown the positive relevance along with difference of plant height from low to high.3. Through 8 kinds of different thermo-sensitive male-sterile wheat line with the same restorer line combinatorial experiment and according to flowering and plant height difference of the parents, we got that flowering difference had the remarkable relevance on the outcrossing rate, and plant height difference not in mixed-production by regression analysis, but plant height difference had the indirect effect to the outcrossing rate(indirect path coefficient=0.23)...