四川常用杂交稻品种对低氮胁迫的响应差异及其筛选方法

Differences in response of hybrid rice to low nitrogen stress and screening methods in Sichuan Province

氮素是水稻生长发育过程中重要的营养元素,为明确杂交水稻对低氮胁迫的响应差异、促进耐低氮水稻品种的选育、构建符合生产需要的耐低氮水稻品种评价体系,以四川常用的26个杂交水稻品种为试验材料,采用田间试验的方法,通过比较低氮处理(LN,纯氮45 kg/hm2)和正常氮处理(NN,纯氮150 kg/hm2)下参试品种的产量构成、顶三叶SPAD动态和分蘖动态等数据,构建能够综合评价水稻耐低氮胁迫能力的评价方法.结果显示:(1)杂交水稻耐低氮产量评价指数(RICY)和耐低氮分蘖动态评价指数(RICT)对低氮处理产量影响最大,其通径系数分别为0.374和0.378;耐低氮返青评价指数(RICR)和耐低氮转色评价指数(RICC)对低氮处理的产量影响相对较小,其通径系数分别为0.249和0.213.(2)低氮条件下,水稻顶3叶SPAD值与水稻产量间的相关系数在返青期、分蘖盛期显著高于其他生育时期.本研究表明耐低氮综合指数RITCM可以用来评价水稻对低氮胁迫的耐受能力,二级指标RICT、RICR和RICC能较好地反映水稻分蘖动态、移栽返青和转色落黄等对低氮胁迫的耐受能力,可为低氮条件下水稻生产提供必要理论依据.

Nitrogen is an important nutrient element in the process of rice growth and development. This study tries to clarify the differences in response of hybrid rice to low nitrogen stress. Aiming to meet the needs of rice production, it attempts to construct an evaluation system of low-nitrogen tolerance rice varieties and to provide theoretical support for rice breeding. Field experiments were conducted with 26 hybrid rice varieties, commonly used in Sichuan as experimental objects. The yield components, dynamic SPAD value of top three leaves, and dynamic tiller number were compared between low nitrogen treatment (LN, pure nitrogen 45 kg/hm2) and normal nitrogen treatment (NN, pure nitrogen 150 kg/hm2). The purpose of this study was to construct an evaluation method that can comprehensively evaluate the tolerance of rice to low nitrogen stress. The results showed that: 1) Yield evaluation index of tolerance to low nitrogen (RICY) and dynamic tiller number evaluation index of tolerance to low nitrogen (RICT) had the greatest effect on the yield of low nitrogen treatment. Their path coefficients were 0.374 and 0.378, respectively. Turning green evaluation index of tolerance to low nitrogen (RICR) and the color conversion evaluation index of tolerance to low nitrogen (RICC) had relatively little effect on the yield of low nitrogen treatment. Their path coefficients were 0.249 and 0.213, respectively. 2) Under the low nitrogen treatment, the correlation coefficient between the SPAD value of top three leaves and rice yield was significantly higher at turning green stage and top tillering stage than that at other growth stages. The results showed that the comprehensive index of tolerance to low nitrogen (RITCM) could be used to evaluate the tolerance of rice to low nitrogen stress. Also, the secondary indicators such as RICT, RICR, and RICC could well reflect the tolerance of rice to low nitrogen stress, expressed as dynamic tiller number, color of transplanting seedlings turning green, and turning the color yellow. It can provide the necessary theoretical basis for rice production under low nitrogen environment.