Increased seed size has greater contribution in yield improvement in recent naked oat (Avena sativa L. subsp. nudisativa) cultivars than cultivars derived from landraces. However, the underlying grain-filling mechanisms associated with seed size and grain yield in naked oat have received limited study. Two field experiments and a pot experiment compared grain-filling mechanisms, seed size and grain yield of ten naked oat cultivars, including old (landraces, released before 1950s) and new (released since 2008) cultivars. In both well-watered and water-deficit conditions, the new cultivars had higher grain yields, higher thousand kernel weights (TKW) and higher grain numbers per spike, but fewer fertile spikes per unit area or per plant, and no significant differences in grain number per unit area or per plant, than old cultivars. The findings in both the field and pot experiments demonstrated that increased grain-filling rate, rather than duration, enhanced seed size (TKW) and grain yield in the new cultivars. The increased grain-filling rate in a new cultivar was associated with higher rates of endosperm cell division and higher number of endosperm cells, compared to that in an old cultivar, but there were no significant differences in starch synthesis enzyme activity and ABA concentration between the old and new cultivars. As a result of current breeding and selection, the increased the grain yield of new cultivars of naked oat is primarily due to increased seed size (increased sink size) arising from a greater number of endosperm cells per grain, and not because of increased enzyme or phytohormonal activity. The larger seed size is important in the production of oats for food rather than for forage.

中文翻译：

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在良好浇水和缺水条件下，加速灌浆速度增加了近期裸燕麦品种的种子大小和籽粒产量

在最近的裸燕麦 (Avena sativa L. subsp. nudisativa) 品种中，增加的种子大小对提高产量的贡献大于源自地方品种的品种。然而，与裸燕麦种子大小和籽粒产量相关的潜在籽粒灌浆机制受到的研究有限。两个田间试验和一个盆栽试验比较了十个裸燕麦品种的灌浆机制、种子大小和籽粒产量，包括旧品种（地方品种，1950 年代之前发布）和新品种（自 2008 年以来发布）。在水分充足和缺水条件下，新品种的籽粒产量较高，千粒重（TKW）较高，每穗粒数较高，但单位面积或单株可育穗数较少，籽粒无显着差异。单位面积或单株数，多于老品种。田间和盆栽试验的结果表明，新品种的籽粒灌浆率增加，而不是持续时间增加，种子大小（TKW）和籽粒产量增加。与旧品种相比，新品种籽粒灌浆率增加与较高的胚乳细胞分裂率和较高的胚乳细胞数量相关，但淀粉合成酶活性和 ABA 浓度在不同品种之间没有显着差异。新旧品种。作为当前育种和选择的结果，裸燕麦新品种的籽粒产量增加主要是由于每粒胚乳细胞数量增加引起的种子大小增加（增加的水槽大小），而不是由于酶或酶的增加所致。 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?植物激素活性。