旱稻渗入系抽穗期根系性状定位

摘 要：目的]研究稻作抗旱的根系特征及其遗传机理，发掘旱稻有利基因，从水旱稻杂交中选育高产耐旱的稻作品种提供理论基础和研究材料。方法]以旱稻豪格劳为供体亲本，水稻沈农265为受体亲本，利用187个SSR标记构建了一套具有180个家系的旱稻渗入系群体，并采用单标记分析法，对拔节期根系6个性状：最长根长、粗根数、总根数、平均最粗根粗、根干重、总干重进行QTL定位。结果]抽穗期共检测到QTL38个，其中影响上述六个性状的QTL数目分别是6、6、4、6、4和12，它们的总贡献率分别为29%、27%、21%、33%、23%和61%。除此，在粗根数和总根数中分别检测到3个和1个来自豪格劳的等位基因的加性效应为负，其余均为正。除平均根粗外，其它5个性状的加性效应都较大。结论]89.5%的渗入位点对以沈农265为遗传背景的渗入系的6个性状根系有促进作用；定位到的影响不同根系性状的QTL多数成簇、集中分布；RM3853附近定位到影响四个性状的QTL，推测是一个在抽穗期与根系性状和抗旱密切相关的基因簇。

QTLs mapping on root traits of introgression lines at heading stage

Abstract：Objective] The objective of our study was to investigate the characters of root traits and the genetic mechanism of rice drought tolerance, explore the favorable genes of upland rice, and provides a theoretical basis and research materials in cultivating high-yield and drought-resistance species from the hybrid generations of upland and lowland rice. Method]A set of 180 introgression lines (ILs) population between an accession of upland rice Haogelao, as donor, and lowland rice Shennong265, as the recipient, was developed using 187 SSR markers. The QTLs at heading stage for six root traits namely MRL (maximum root length), TRN (thick root number), TNR (total numbers of root), ART (average root thickness), RDW (root dry weight) and TPW (total plant mass weight) were mapped using single-marker regression analysis. Result]A total of 38 putative QTLs for six root traits were detected using single marker analysis at heading stage. 6 QTLs associated with MRL were detected and the total contribution rate was 29%. A total of 6 QTLs affected to TRN were found at jointing stage and explained 27% phenotypic variance. 4 QTLs about TNR were detected and the total contribution rate was 21%. 6 QTLs which controlled the ART were detected and can explain 33% phenotypic variance. 4 QTLs related to RDW were identified in this study and the total contribution rate was 23%. 12 QTLs associated with TPW were detected and which could explain 61% of the phenotypic variance. 3 and 1 QTLs derived from Haogelao caused a decrease effect of TRN and TNR respectively. The additive effects of the characters were relatively large except ART. Conclusion] 89.5% QTLs derived from upland rice Haogelao improved the six root traits of the ILs in genetic background of lowland rice Shennong265. QTLs about different root traits distributed most in clusters on chromosome. Four QTLs were detected near RM3853. So, we speculated that RM3853 must be a new gene cluster related to root traits and drought tolerance of rice at heading stage.