The ability to tolerate salt differs with the growth stages of rice and thus the yield components that are determined during various growth stages, are differentially affected by salt stress. In this study, we utilized chromosome segment substitution lines (CSSLs) from Nona Bokra, a salt-tolerant indica landrace, with the genetic background of Koshihikari, a salt-susceptible japonica variety. These were screened to find superior CSSLs under long-term saline conditions that showed higher grain yield and yield components in comparison to Koshihikari. One-month-old seedlings were transplanted into a paddy field without salinity. These were allowed to establish for 1 month further, then the field was flooded, with saline water maintained at 7.41 dS m-1 salinity until harvest. The experiments were performed twice, once in 2015 and a targeted study in 2016. Salt tolerance of growth and reproductive stage parameters was evaluated as the Salt Effect Index (SEI) which was computed as the difference in each parameter within each line between control and saline conditions. All CSSLs and Koshihikari showed a decrease in grain yield and yield components except panicle number under salinity. SL538 showed a higher SEI for grain yield compared with Koshihikari under salinity throughout the two experiments. This was attributed to the retained grain filling and harvest index, yet the mechanism was not due to maintaining Na+, Cl- and K+ homeostasis. Few other CSSLs showed greater SEI for grain weight under salinity compared with Koshihikari, which might be related to low concentration of Na+ in leaves and panicles. These data indicate that substitution of different Nona Bokra chromosome segments independently contributed to the maintenance of grain filling and grain weight of Koshihikari under saline conditions.

中文翻译：

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利用盐田稻田光光遗传背景评价稻谷产量和Nona Bokra染色体片段替代系的产量构成。

耐盐能力因水稻的生长阶段而异，因此，在各个生长阶段确定的产量成分受盐胁迫的影响不同。在这项研究中，我们利用耐盐的land地方品种Nona Bokra的染色体片段替代系（CSSL），结合了对盐敏感的粳稻越光（Koshihikari）的遗传背景。筛选它们以发现在长期盐水条件下优良的CSSL，与Koshihikari相比，这些CSSLs显示出更高的谷物产量和产量构成要素。将一个月大的幼苗移植到无盐的稻田中。允许它们再建立1个月，然后用保持在7.41 dS m-1盐度的盐水将水淹没直到收获。实验进行了两次，在2015年进行一次，在2016年进行一项针对性研究。生长和生殖阶段参数的耐盐性被评估为盐效应指数（SEI），其计算方法是对照条件和盐水条件在每条线中每个参数的差异。在盐度下，除穗数外，所有CSSLs和越光均表现出籽粒产量和产量构成要素的下降。在整个两个实验中，在盐度下，SL538的谷物单产SEI均高于Koshihikari。这归因于保留的谷物充实和收获指数，但其机理并非由于维持了Na +，Cl-和K +稳态。在盐度下，很少有其他CSSLs与Koshihikari相比显示出更大的SEI，这可能与叶片和穗中Na +的浓度低有关。