ABSTRACT

Increasing the yield potential of rice (Oryza sativa) is the main objective of breeders and cultivators engaged in rice improvement programs. Erect panicle (EP) rice is generally high-yielding with panicles that remain non-curved until maturation. The aim of our study was to evaluate the association of agronomic traits with rice productivity in EP rice. Here, we used the recombinant inbred lines (RILs), crosses between Liaojing5 (erect panicle japonica type) and Wanlun422 (high-yielding indica type). The yield varied among the RILs, and the flag leaf length of EP RILs was negatively correlated with the yield; however, the correlation was not significant in the non-EP RILs. The flag leaf length of the EP RILs was also negatively correlated with biomass increase during the late ripening stage. This may reflect the canopy structure of the EP RILs with short flag leaves which had a larger leaf area index in the lower strata. Additionally, the chlorophyll content in the lower leaf significantly differed among the EP RILs with flag leaves of different lengths, resulting in a higher photosynthetic ability of the lower leaf of EP RILs with short flag leaves. In the present study, an EP line, which has the shortest flag leaf, showed a higher yield than Wanlun422 in both years. EP RILs with short flag leaves might show a higher canopy photosynthetic rate in the later ripening stage; therefore, this trait could be a potential phenotypic marker for achieving high yield of EP rice.

摘要

提高水稻的产量潜力（Oryza sativa) 是从事水稻改良计划的育种者和栽培者的主要目标。直立圆锥花序（EP）水稻通常产量高，圆锥花序在成熟前保持不弯曲。我们研究的目的是评估 EP 水稻农艺性状与水稻生产力的关系。在这里，我们使用重组自交系（RILs），在辽荆5（直立穗粳型）和万轮422（高产籼型）之间杂交。RILs的产量不同，EP RILs的旗叶长度与产量呈负相关；然而，在非 EP RIL 中，相关性并不显着。EP RILs 的旗叶长度也与成熟后期的生物量增加呈负相关。这可能反映了EP RILs的冠层结构，具有较短的旗叶，在较低地层具有较大的叶面积指数。此外，不同剑叶长度的EP RILs下叶叶绿素含量差异显着，导致短剑叶EP RILs下叶的光合能力更高。在本研究中，具有最短旗叶的EP系在这两年的产量均高于万轮422。短旗叶的EP RIL在成熟后期可能表现出较高的冠层光合速率；因此，该性状可能是实现 EP 水稻高产的潜在表型标记。导致具有短旗叶的 EP RILs 的下叶具有更高的光合能力。在本研究中，具有最短旗叶的EP系在这两年的产量均高于万轮422。短旗叶的EP RIL在成熟后期可能表现出较高的冠层光合速率；因此，该性状可能是实现 EP 水稻高产的潜在表型标记。导致具有短旗叶的 EP RILs 的下叶具有更高的光合能力。在本研究中，具有最短旗叶的EP系在这两年的产量均高于万轮422。短旗叶的EP RIL在成熟后期可能表现出较高的冠层光合速率；因此，该性状可能是实现 EP 水稻高产的潜在表型标记。