【作者】 王晓楠；

【导师】 李卓夫；

【作者基本信息】 东北农业大学 ， 作物遗传育种， 2007， 硕士

【摘要】 春小麦是黑龙江省主要粮食作物，然而近年来，由于与大豆、玉米、水稻相比，小麦的生产效益低，黑龙江省春小麦的种植面积已从过去的200万公顷下降到现在的不足20万公顷。虽然通过品种改良，黑龙江省春小麦的品质得到较大程度地提高，但单产水平低成了限制小麦生产效益的主要因素。小麦产量是由单位面积穗数、穗粒数、千粒重三者相互作用的结果，目前黑龙江省春小麦的播种密度控制在600～900万株／hm~2之间，种植密度已达合理群体的上限；而小麦千粒重又受品种特性和环境条件的制约，增加幅度有限，所以，穗粒数就成了限制春小麦产量提高的瓶颈。本试验从春小麦分化小穗数和结实率这两个方面出发，围绕小穗数分化过程中基因型间糖分代谢差异、基因型间结实率差异的原因、氮肥处理对小麦品种结实率的影响以及穗粒数与千粒重的关系等四个问题进行深入研究，试验结果表明：1．小穗数分化过程中，小麦与小黑麦植株体内的可溶性总糖、蔗糖含量差异显著，表现为小黑麦植株的可溶性总糖、蔗糖含量显著高于小麦。小麦品种间体内蔗糖含量进入二棱期后存在差异，表现为随植株体内蔗糖含量提高，小麦品种分化的总小穗数增多。小麦、小黑麦小穗分化过程中植株体内的果糖含量在单棱期以前没检测到，进入单棱期以后小麦、小黑麦植株体内的果糖含量仍然很低且差异不显著。2．小麦穗分化过程中，加快伸长期和单棱期的分化速率，延长穗分化的总天数，并增加二棱期的天数对增加每穗总小穗数有利。3．限制春麦结实率提高的时期是从幼胚形成至乳熟期的阶段。减少幼胚的退化率是提高春麦结实率进而提高穗粒数的关键。4．从幼胚形成到籽粒达1／3满仁状态，增加茎、叶中可溶性总糖和蔗糖的含量；从籽粒达1／3满仁至乳熟期，提高茎、叶可溶性总糖和蔗糖的输出量，可有效减少幼胚退化。5．氮肥处理显著改变小花分化的数量和幼胚败育率的高低。小花分化的数量受叶干物质输出量和叶中糖分代谢的影响。在小花分化过程中，叶干物质输出量与小花分化的数量密切相关；叶中可溶性总糖、果糖、蔗糖的输出量越高，分化的总小花数越多。适宜的氮肥处理能促进小花分化过程中叶干物质和叶中可溶性总糖、果糖、蔗糖的输出。幼胚形成后茎、叶中的可溶性总糖、蔗糖输出量、旗叶中可溶性总糖输出量均影响着幼胚败育率。适宜的氮肥处理能促进幼胚形成后茎、叶、旗叶中可溶性总糖、蔗糖的输出，减少了幼胚的退化。6．在三个氮肥处理下，小麦穗粒数与千粒重的关系因品种而异。各品种均在N1处理下穗粒数最多。东农126在三个氮素处理上千粒重差异不显著；龙辐9在N1处理下的千粒重最高；加—T在N2处理下的千粒重最高。籽粒灌浆过程中旗叶干物质的变化量与千粒重的关系最密切。茎中干物质的变化量虽最大，但对千粒重的影响不明显。所以在籽粒灌浆期间如何加快旗叶中积累的物质输出是增加千粒重的关键。更多还原

【Abstract】 Spring wheat is one of the improtant edible crops in Heilongjiang Provence of China. Recently,however, the planting area of spring wheat in this provence was descended from 2 million hactarsto less than 200 thousand hactars for the lower economic benefits than other crops such assoybean、corn and rice. The lower yield of spring wheat has become the main limiting factors forincreasing its benefits though the quality of the crop has been largely improved genetically. Theyield would be divided into three components e.g. spikes/hm~2、kernels/spike and 1000 grainsweight. Now 6-9 million plants/hm~2 reached to top of the normal wheat planting desity inHeilongjiang; 1000 grains weight of wheat was also restricted to 30-35 g by cultivars andenvironment in the province. So the kernels/spike became the bottleneck for high yield of springwheat.The diversity of genotypes in carbohydrate metabolism in the spikelets formation、the causeof the variation among genotypes in seed setting, the effect of N fertilization to seed settingpercentage of wheat cultivars and the relation between kernels per spike and 1000 grains weightwere studed in the trial for increasing spikelets and kernels in spring wheat. The results showed:. The significant differences among genotypes in the contents of both soluble totalsaccharinity and sucrose in plants were found in the process of spikelets differentiation in wheatand triticale, and the level of those two compounds in triticale was higher than that in wheat. Thedifference of sucrose content occurred among wheat cultivars after double ridge stage. A increaseof total spikelets was observed with the raise of sucrose in plant of wheat.No fructose was measured in the plants of wheat and triticale before the single ridge stage andafter the very stage the level of this ingredient was no different between the two species.2. The quicker rate of the elongated apex and single ridge stages, the longer of spikedeveloping and especially the double ridge durations in the process of the spike differenciationwould be advantage for increase of spikelets per spike in wheat.3. The period from embryo initiation to full filling of grain seemed to be the limit of grain setin spring wheat. The reduction of the embryo abortion would be the key of increase of seed set andfurthermore kernels of spike.4. The increase of the contents of both soluble total sugar and sucrose in the stem and leaves inthe period from embryo formation to 1/3 filling state and of the output amount of the same materials from the stem and leaves in the period from 1/3 filling to full filling states would reducethe embryo abortion effectively.5. The nitrogen fertilizer appliction could make improvement obviously in more florets andlower young embryo abortion. The florets of spike seemed to be affected by the sugar metabolismin leaves and dry-matter output from leaves. The higher the dry-matter output and amount ofsoluble total sugar、fructose and sucrose from leaves, the more the florets of spike in wheat. Theincrease of output of dry-matter and the soluble total sugar、fructose and sucrose from leaves wasobserved in the floret differentiation with optimum application of N fertilizer.The rate of the young embryo abortion could be influenced by the amount of soluble sugar andsucrose transportation from stem、leaves and flag leaf after embryo initiation. The embryo abortionreduced because of the increase of the output of those elements in the optimum N treatment.6. The relationship of grains per spike and 1000-grain weight might be varied among wheatcultivars in 3 nitrogen fertilizer treatments. The most kernels of spike presented in N1 in allcultivars. No diversity of 1000-grain weight of DongNong126 was found in all 3 N treatments. Thehighest 1000-grain weight of LongFu 9 was in N1 and that of Jia-T in N2. The varying amount ofdry-matter in the flag leaf had the most close relation to 1000-grain weight in the grain fillingperiod of wheat. The changing amount in stem had no influence on 1000-grain weight though itvaried largest. The key of increase 1000-grain weight of wheat was how to speed up the outputamount of dry-matter from flag leaf in the grain filling period.更多还原