| The massive-spike-type of winter wheat cultivars Yumai66 was studied under the high-yielding condition with a multi-spike-type cultivars Yumai49,as control. The main results were as follows :1. There were differences both grain yield characteristics, which indicated that Yunai66 had lower grain yield than that of Yumai49, but more kernels per spike and higher kernel weight than that of Yumai49.This differences showed that the spike per united area is limited factor of the grain yield which will be enhanced .2.In the peak of tiller periods and tiller senescence periods, the differences of change of endogenous hormones contents between Yumai66 and Yumai49 were existed. Contents of IAA, ZR+Z of Yumai66 main-culms were respectively 167.7ng/g-FW> 220.1ng/g-FW, which were lower than that of Yuami49,but ABA contents higher. Contents of IAA , ZR+Z of two cultivars showed same trends, but with growing ,gap of contents of IAA, ZR+Z of Yumai66 between main-culms and tillers became big. The differences of two cultivars were existed in contents of ABA, both main-culms and tillers of Yumai49 maintain consistent, contents of tillers of Yumai66 increased. 3. With change of endogenous hormones, young-panicle-differentiationof tiller I, II of Yumai66 became slow and gap with main-culms large in double-ridge stage. In tiller senescence periods, ages of leaf between tillers and main-culms of Yumai66 became big ,in the meantime, gap of ages of leaf among tillers I, II and main-culms of it were respectively 3.2, 4.1. With growing ,dry matter accumulation(DMA) of main-culms, tiller I, II changed respectively from 0.474g, 0.161g, 0.190g at the turning green stage(2/18) to 0.625g^ 0.075g> 0.072g at jointing stages(3/25). On the Contrary, there were consistent between main-culms and tillers for Yumai49 about young-panicle-differentiation (tillers having been come up with main-culms at the late double-ridge ) .. DMA(main-culms, tiller I , II changed respectively from 0.207g, 0.178g, 0.187g at the turning green stage to 0.251g, 0.219g, 0.228g at jointing stages), ages of leaf (gaps of tiller I, II with main-culms keep about 3.1, 3.6.). Therefore, that formation of spike of massive-spike-type Yumai66 were much lower than that of control account for changes of endogenous hormones accordingly lead to changes young-panicle-differentiation, DMA, ages of leaf.4.Effects of spacing form on leaf area index(LAI), canopy apparent photosynthesis(CAP)rate were obvious. Under basic seedling 225 × 104/hm2, 300 × 104/hm2 condition, LAI of 16.7cm spacing form(Bi) larger than that of 23..3cm width (B3) and 23.3cm spacing form (B2). Under basic seedling 375×l04/hm^ 450×l04/hm2 condition, only before anthesis ,B1>B3>B2 . Under different basic seedling condition, CAP of different spacing form showed as a single-peaked curve and the peak value reached at anthesis. 16.7cm spacing form, basic seedling 375×104/hm2 treatment was the highest.. Under the identical basic seedling condition. DMA of16.7cm spacing form was the most;second,23.3cm width spacing form;third,23.3cm spacing form. There were same trends in the apparent photosynthesis per plant rate, which its peak was at initial grain filling .In short ,small spacing form or width spacing form have larger advantages in photosynthesis characteristics,DMA etc .5. Change trends of LAI with different density treatment were identical, the highest value of which was at anthesis. Before anthesis ,along increasing of basic seedling ,LAI of different treatment increase and after anthesis , LAI of basic seedling 375×104/hm2 was the highest . LAI of Yumai49 was lager than that of Yumai66 with different density treatments before anthesis ,but decreased after anthesis and became the smallest at grain filling stage .the Extinction Coefficient(K) of Yumai66 ,with density increasing, increased and became the largest at anthesis ,but lower than that of Yumai49 .CAP of different treatments showed the same trends .Before erecting ,the more density, the more CAP .At late grain filling , CAP...
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