Yu Chuan-Yuan, Liu Yu-Qiang, Jiang Ling, Wang Chun-Ming, Zhai Hu-Qu, Wan Jian-Min
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Research Center of Plant Gene Engineering of Jiangsu Province, Nanjing 210095, China.
Yi Chuan Xue Bao. 2005 Sep;32(9):948-54.
Tiller angle is one of the most important morphological characters that has a significant effect on the formation of rice high-yield population. The tiller angles were measured in a japonica/indica RIL population with 71 lines and a genome-wide chromosome segment substitution line (CSSL) population with 65 lines at two experimental sites. A transgressive segregation was observed in both populations. QTL analysis of tiller angle was conducted based on the saturated RFLP marker linkage map and the CSSL graphical genetype. Five main-effect QTLs and three pairs of epstatic loci were detected in the RIL population. A main QTL, qTA-9, located on chromosome 9 at XNpb108 - C506, was identified at both experiment sites. The positive allele TA-9(I) on qTA-9 was contributed by indica rice IR24 with 28.6% average contribution to variance. Meanwhile, an analysis of CSSL graphical genetypes also showed that there was a positive allele on the IR24 chromosome substitution segment delimited by RFLP marker C609 and C506 with approximate 15 cM interval, which proved the existence of qTA-9. The TA-9(I) could increase tiller angle by about 15 degrees in japonica Asominori background under the two environments. The measurement of the F1 from the cross between background parent and CSSL AIS68 with TA-9(I) and the analysis of F2 population indicated that the TA-9(I) was an incomplete dominant gene. Genetype x environment interaction(G xE) was not widely present except a pair of epistatic loci with 5.32% contribution to variance of tiller angles and a relatively small additive effect. The combining action of the additive effect of the genes from both parents and the two-loci epistasis-effect may be responsible for the transgressive segregation of tiller angle in rice population. The value and approach of application of TA-9(I) in hybrid rice breeding program were discussed.
分蘖角度是对水稻高产群体形成有显著影响的最重要形态特征之一。在两个试验地点对由71个株系组成的粳稻/籼稻重组自交系群体和由65个株系组成的全基因组染色体片段代换系（CSSL）群体的分蘖角度进行了测量。在两个群体中均观察到超亲分离现象。基于饱和RFLP标记连锁图谱和CSSL图形基因型对分蘖角度进行了QTL分析。在重组自交系群体中检测到5个主效QTL和3对上位性位点。在两个试验地点均鉴定出一个位于第9染色体XNpb108 - C506处的主QTL，即qTA - 9。qTA - 9上的正向等位基因TA - 9(I)由籼稻IR24贡献，对变异的平均贡献率为28.6%。同时，对CSSL图形基因型的分析还表明，在由RFLP标记C609和C506界定的、间隔约15 cM的IR24染色体代换片段上存在一个正向等位基因，这证明了qTA - 9的存在。在两种环境下，TA - 9(I)在粳稻Asominori背景下可使分蘖角度增加约15度。对背景亲本与携带TA - 9(I)的CSSL AIS68杂交所得F1的测量以及对F2群体的分析表明，TA - 9(I)是一个不完全显性基因。除了一对对分蘖角度变异贡献率为5.32%且加性效应相对较小的上位性位点外，基因型×环境互作（G×E）并不广泛存在。双亲基因的加性效应与两位点上位性效应的联合作用可能是水稻群体中分蘖角度超亲分离的原因。讨论了TA - 9(I)在杂交水稻育种计划中的应用价值和方法。
