ABSTRACT We examined the effect of panicle position relative to canopy and of panicle angle on pollination and floret sterility in rice at anthesis in a paddy field. We set panicles of pot-grown rice at the flowering stage either upright (0°) or inclined (30°), either above or at canopy height (Experiment 1) and either beneath or at canopy height (Experiment 2), in three replications each. In Experiment 1 and Experiment 2, panicle inclination at 30° increased the percentage of florets with <20 total pollen grains on the stigma (TP20) by 21% and 27%, increased the percentage of florets with <10 germinated pollen grains on the stigma (GP10) by 21% and 30%, and increased floret sterility by 10% and 26%, respectively. Floret sterility was correlated with GP10 in all trials. GP10 was correlated with TP20. The effect of position on floret sterility was not significant. We conclude that panicle inclination at 30° significantly increased floret sterility even under the canopy condition. Uprightness of panicles should be an important objective in rice breeding and production. Abbreviations TP20, percentage of florets with <20 total pollen grains on the stigma; GP10, percentage of florets with <10 germinated pollen grains on the stigma. Graphical Abstract

中文翻译：

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冠层中的穗角和穗位置如何决定水稻（Oryza sativa L.）的授粉和结实

摘要 我们研究了穗位相对于冠层的位置和穗角对稻田开花期水稻授粉和小花不育的影响。我们在开花期将盆栽水稻的圆锥花序设置为直立 (0°) 或倾斜 (30°)，高于或在冠层高度（实验 1）以及低于或在冠层高度（实验 2），三个重复每个。在实验1和实验2中，30°的圆锥花序倾斜使柱头（TP20）上总花粉粒<20的小花百分比增加了21％和27％，增加了柱头上发芽花粉粒<10的小花百分比(GP10) 分别提高了 21% 和 30%，小花不育率分别提高了 10% 和 26%。在所有试验中，小花不育与 GP10 相关。GP10 与 TP20 相关。位置对小花不育的影响不显着。我们得出结论，即使在冠层条件下，30° 的穗倾斜度也显着增加了小花的不育性。穗的直立性应成为水稻育种和生产的重要目标。缩写TP20，柱头上总花粉粒<20的小花百分比；GP10，柱头上具有 <10 个发芽花粉粒的小花百分比。图形概要