基于控制授粉技术的玉米弱势粒发育与库特征的关系

明确弱势粒败育和灌浆受限与其库容量或库活性关系，对于探讨弱势粒调控途径、实现密植群体产量挖潜具有重要意义。本研究以典型玉米杂交种郑单958和先玉335为材料，在控制授粉条件下(不完全授粉IcP、完全授粉CP)，比较成功发育弱势粒(IcP处理)和发育不良弱势粒(CP处理)的库容量和库活性及籽粒灌浆参数的差异。结果表明，不同控制授粉处理下，玉米弱势粒胚乳细胞增殖过程和最大胚乳细胞数无显著差异；IcP处理弱势粒可溶性酸性蔗糖转化酶(SAI)活性显著高于CP处理，平均差异和最大差异分别达12.6%和21.8%，且实测百粒重、籽粒终极生长量、最大灌浆速率和平均灌浆速率皆表现为IcP处理高于CP处理。可见，玉米果穗顶部弱势粒败育或灌浆停滞不受其库容量的限制，籽粒形成期的库活性是弱势粒败育或灌浆受限的核心限制因子。

Relationship of Inferior Kernel Setting with Sink Strength under Controlling Pollination

Clarifying the relationship of sink capacity and/or sink activity with kernel abortion and/or filling stagnation of inferior kernels, is of great importance for closing the yield gap by improving the grain filling of inferior kernels of maize. In this present study, two typical commercial maize hybrids Zhengdan 958 and Pioneer 335 were planted at two locations. At silking stage, two pollination treatments, incomplete pollination (IcP) and complete pollination (CP), were imposed to each cultivar at each location. The objective of incomplete pollination, in which the pollinated filaments within the basal region of the ear was decreased by handing-pollinating, was to stimulate the inferior kernel set in the apical region of the ear, where the inferior kernels should be aborted or filling-stagnated in complete pollination. The sink capacity, sink activity and grain filling parameters were compared within IcP and CP treatments. The endosperm cell division process and the maximum endosperm cell number of inferior kernels showed no difference between IcP and CP treatments, while the soluble acid invertase activity of IcP was significantly higher than that of CP, by 12.6% on an average and 21.8% at the maximum. Furthermore, the actual 100-kernel weight, the stimulated final kernel weight, the maximum kernel-filling rate and the mean kernel-filling rate of IcP treatment were also higher than those of CP. The results suggested that the abortion and/or filling stagnation of inferior kernels of maize is not limited by its sink capacity; sink activity during blister stage is the primary limited factor of the abortion and/or filling stagnation of inferior kernels.