野生四倍体二粒小麦(Triticum dicoccoides)农艺性状的QTLs

摘要

The objective of the present study is to reveal and map quanti tative trait loci (QTL) conferring agronomic traits in tetraploid wheat, Triticum dicoccoides. An F2 mapping population with 150 indivi duals was developed by crossing T.dicoccoides accession Hermon H 52 with T.durum cultivar Langdon. Two versions of PCR-based mol ecular framework maps were constructed each mainly comprising of codominant mark ers and the dominant markers in coupling phase. Total map size exceeded 3000 cM and covered the entire genome. The following 11 traits of agronomic importance w ere measured: Plant height (HT), heading date (HD), spike number/plant (SNP), sp ikelet number/spike (SLS), spike weight/plant (SWP), single spike weight (SSW), kernel number/plant (KNP), kernel number/spike (KNS), kernel number/spikelet (KN L), 100-grain weight (GWH) and grain yield/plant (YLD). A new computer program MultiQTL was used to conducted the single-QTL analysis. Forty-nine QTLs were r evealed for the 11 traits ranging from two (HT) to seven (GWH) QTLs per trait. A ll the QTLs were proven significant at 5% or higher level by permutation test. B inomial test indicated that large number of QTLs were not detected by chance, an d so were real. The QTLs were not randomly distributed among chromosomes and alo ng chromosomes. Most of the QTLs clustered in six regions on four chromosomes. T wenty-three major QTLs (p＜0.001) were identified for the 11 t raits, and more than half (17) of them clustered in three regions on chromosomes 2A and 5A. Many of the QTLs were mapped to very small chromosomal segments of ＜5 cM. Some cryptic beneficial alleles were uncovered from T.dicoccoide s. The present study confirms that T.dicoccoides is a va luable germplasm for wheat improvement, could accelerate the genetic analysis of wheat, and has laid a solid foundation for QTL introgression and cloning from T.dicoccoides.%本研究对四倍体小麦与农艺性状关系密切的数量性状位点(QTL)进行分析和作图.利用二粒小麦(T.dicoccoides) Hermon H52和栽培品种langdon (T.durum)杂种F2中的150个单株进行作图.建立了显性、共显性两种以P CR为基础的分子框架图模型.该图谱超过3000cM,覆盖整个基因组.分析了11个重要农艺性状:株高(HT),抽穗期(HD),单株穗数(SNP),每穗小穗数(SLS),单株穗重(SWP),单穗重( SSW),单株粒数(KNP),单穗粒数(KNS),小穗粒数(KNL),百粒重(GWH),和单株籽粒产量(Y LD).运用新的计算机软件MultiQTL分析处理单个QTL,11个性状共检测到49个QTL位点.每个性状的QTL数目从2个(HT)到7个(GWH)不等.所有的QTLs通过统计检验在5%或更高的水平上达到显著;正态检验表明大多数QTLs是真实存在.这些QTL主要分布在四条染色体上的6个区域,并不是在染色体上随机分布,其中与11个性状有关的23个主要QTLs,一半以上分布在2A 和5A上的3个区域,而且许多QTLs排列在非常短的染色体片段上(小于5cM).在T.di coccoides中发现一些有利隐蔽等位基因.这一研究说明T.dicoccoides在小麦改良中是一个珍贵的种质资源,对它进行研究,能加快小麦的遗传分析,促进T.dicoccoides中有利基因向普通小麦渗透并对其基因克隆打下了坚实的基础.