Spikelet Sterility is Associated with a Lack of Assimilate in High-Spikelet-Number Rice
Spikelet Sterility is Associated with a Lack of Assimilate in High-Spikelet-Number Rice
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DOI：
10.2134/agronj2013.0115
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发表时间：
2013-11-01
期刊：
影响因子：
2.1
通讯作者：
Honda, Tohru
中科院分区：
文献类型：
--
作者：
Kobata, Tohru;Yoshida, Haruko;Honda, Tohru
新稻（Oryza sativa L.）小穗数高的基因型有时由于灌浆速率低而不能表现出其高产潜力。我们的目的是评估小穗不育对籽粒灌浆的影响，在HS品种，并确定是否开花前后的同化因子与小穗不育。两个粳稻×籼稻和一个粳稻×爪哇HS品种的种植和比较单一的标准籼稻和粳稻品种。较低的小穗肥力（较高的不育性）是伴随着较低的填充率的小穗（观察/潜在的粮食产量）在品种和HS品种承载不同的小穗数量作为N肥处理的函数。为了增加同化物供应到整个穗或穗下部，在抽穗时将植株密度减半或在抽穗中期去除穗的上半部分。密度减半，特别是去除上部穗，显着增加小穗育性的1.3至1.5倍，在穗下部的HS品种。在开花前后不利的同化条件下，HS品种的小穗育性容易降低。在HS品种中，去除上部穗显著增加了下部穗位雌蕊上的花粉数的1.3倍。这些结果表明，小穗不育在穗下部降低籽粒灌浆的HS品种和开花前后的同化物供应不足的结果，在小穗不育通过错误的授粉过程中。
New rice (Oryza sativa L.) genotypes bearing a high spikelet number (HS) occasionally cannot show their high yield potentials due to the lower grain-filling rate. Our objectives were to evaluate the effect of spikelet sterility on grain filling in HS cultivars and to determine whether the assimilation factor around anthesis is related to spikelet sterility. Two japonica x indica and one japonica x javanica HS cultivars were grown and compared with single-standard indica and japonica rice cultivars. Lower spikelet fertility (higher sterility) was accompanied by a lower filling percentage of spikelets (observed/potential grain yield) across cultivars and within the HS cultivars bearing different spikelet numbers as a function of N fertilizer treatments. To increase assimilate supply into the whole or lower part of the panicle, plant density was halved at heading or the upper half of the panicle was removed during the middle-heading period. The halved density, and the removal of the upper panicle in particular, significantly increased spikelet fertility by 1.3 to 1.5 times in the lower part of the panicle in the HS cultivars. The spikelet fertility in HS cultivars could easily be decreased under adverse conditions of assimilation around flowering. The removal of the upper panicle in the HS cultivars significantly increased by 1.3 times the pollen count on the pistil in the low panicle position. These results suggest that spikelet sterility in the lower part of the panicle lowers grain-filling in the HS cultivars and that inadequate assimilate supply around flowering results in spikelet sterility through a fault in the pollination process.