Low-temperature response to major agronomic traits by using recombinant inbred line （RIL） populations derived from towada/kunmingxiaobaigu

Chinese. 【目的】培育重组自交系群体是发掘或定位水稻孕穗开花期耐冷性QTL的重要基础。本研究通过培育＂十和田/昆明小白谷＂重组自交系群体（RIL）,在云南自然低温条件下,分析RIL的株高、穗长、穗伸出度、单株结实率、特定结实率和穗粒数等主要农艺性状低温反应,为耐冷性相关性状的遗传分析及QTLs定位等提供研究材料和参考。【方法】以由230个家系组成的＂十和田/昆明小白谷＂RILs及其亲本为试验材料,2001年在昆明和呈贡,2002年在昆明和剑川,2003年在昆明进行了孕穗开花期耐冷性自然低温鉴定,并对株高、穗长、穗伸出度、单株结实率、特定结实率和穗粒数等性状进行方差和相关分析。【结果】株高、穗伸出度和穗粒数3性状以基因型控制为主,穗长以基因型×环境互作为主,单株结实率和特定结实率以试点环境控制为主。在5种生长环境下,上述6个性状F值为4.019～97.284,株系间均具有极显著差异。在每个试点环境条件下,单株结实率与特定结实率都表现出极显著的正相关关系,相关系数为0.826～0.885;株高与穗长和穗伸出度均表现出极显著的正相关关系。在5种不同生长环境下6个性状变异系数大小顺序依次是特定结实率（66.3%）〉穗伸出度（57.4%）〉单株结实率（37.2%）〉穗粒数（16.2%）〉株高（9.6%）〉穗长（6.4%）;特定结实率、穗伸出度和单株结实率反应最敏感,穗粒数、株高和穗长不太敏感。【结论】本研究培育的＂十和田/昆明小白谷＂RIL可作为水稻孕穗开花期耐冷性研究的遗传材料;特定结实率、穗伸出度和单株结实率是孕穗开花期自然低温胁迫反应最敏感的性状指标,株高、穗长和穗粒数的变异与孕穗开花期低温胁迫的相关程度还有待进一步研究;在水稻孕穗开花期耐冷性自然鉴定评价中,必须进行多年多点的鉴定评价。

English. [Objective] Development of the recombinant inbred line populations is an important basis for detection of QTLs of cold tolerance at booting stage in rice. This study was to offer reference data and ideal populations for QTLs and genetic analysis on major agronomic traits of cold tolerance through developing ＂Towada/Kunmingxiaobaigu＂ （RILs）. Low-temperature response of major agronomic traits of plant height （PH）, panicle length （PL）, panicle exsertion （PE）, spikelet fertility （SF）, specific spikelet fertility （SSF） and spikelets per panicle （SPP） were analyzed under natural low-temperature growing environments in Yunnan Province. [Method] A set of 230 RILs derived from the cross of Towada and Kunmingxiaobaigu. Their parents were tested for the analysis of variance and correlation of PH, PL, PE, SF, SSF and SPP, in Kunming and Chenggong in 2001, in Kunming and Jianchuan in 2002, and in Kunming in 2003, respectively. [Result] Results showed that PH, PE and SPP were mainly attributed by genotypes. PL was mainly influenced by genotypes ~ environments interaction. SF and SSF were mainly attributed by environments. Under the five different growth environments, F values of the six agronomic traits mentioned above ranged from 4.019 to 97.284. Significant difference was revealed between the lines. Under each environment, it indicated significantly positive correlation between SF and SSF, with correlation coefficients ranged from 0.826 to 0.885. It indicated significantly positive correlation between PH, PL and PE. Under the five different growing environments, variation coefficients of the six characters ordered in SSF （66.3%）〉 PE（57.4%）〉SP（37.2%）〉SPP（16.2%）〉PH（9.6%）〉PL（6.4%）. SSF, PE and SF were most sensitive to low temperature stress at booting stage, while SPE PH and PL being least. [ Conclusion ] The RILs of＂Towada/Kunmingxiaobaigu＂ can be used as a genetic population to investigate cold tolerance at booting stage. SSF, PE and SF are most sensitive to cold tolerance at booting stage in rice. So far the variation of PH, PL and SPP related to cold tolerance is not clear under natural low-temperature environment. More tests in different environments and years are required to identify and evaluate cold tolerance at booting stage in rice.