Stem lignin content(SLC) in common wheat(Triticum aestivum L.) contributes to lodging resistance. Caffeic acid 3-O-methyltransferase(COMT) is a key enzyme involved in lignin biosynthesis. Characterization of TaCOMT genes and development of gene-specific markers could enable marker-assisted selection in wheat breeding. In the present study, the full-length genomic DNA(gDNA) sequences of TaCOMT genes located on chromosomes 3 A, 3 B, and 3 D were cloned by homologous cloning. Two allelic variants, TaCOMT-3 Ba and TaCOMT-3 Bb, were identified and differed by a 222-bp insertion/deletion(InDel) in the 3′-untranslated region(3′-UTR). A co-dominant gene-specific marker based on this InDel was developed and designated as Ta COMT-3 BM. A total of 157 wheat cultivars and advanced lines grown in four environments were used to validate the associations between allelic patterns and SLC. The SLC of cultivars with TaCOMT-3 Ba was significantly(P<0.01) higher than that of those with TaCOMT-3 Bb, and the marker TaCOMT-3 BM could be effectively used in wheat breeding.
FU Lu-pingXIAO Yong-guiYAN JunLIU Jin-dongWEN Wei-eZHANG YongXIA Xian-chunHE Zhong-hu
Improved lodging resistance is important for achieving high yield in irrigated environments.This study was conducted to determine genotypic variation in lodging resistance and related morphological traits among winter wheat cultivars planted at two densities,and to identify key traits associated with lodging resistance.Lodging performance of 28 genotypes,including 24 released cultivars and four advanced lines,was evaluated at 250 plants per square meter and 500 plants per square meter in Shandong province during the 2008–2009 and 2009–2010 crop seasons.At the higher density,the average grain yield was 2.6%higher,even though lodging score rose by as much as 136%.The higher planting density increased lodging through increased leaf area index(LAI),plant height,center of gravity and length of basal internodes,and reduced grain weight per spike and diameter of the lower two stem internodes.LAI,center of gravity and diameter of first internodes,as the important indicators for lodging resistance,were significantly correlated with lodging score,with R=0.62,0.59 and–0.52(P<0.01),respectively.Plant pushing resistance was significantly associated with diameter and length of the first internodes(R=0.71–0.77,P<0.01),indicating it could be used to assess the strength of the lower stem.Higher planting density could be used to select genotypes with lodging resistance in irrigated environments.Cultivars carrying high plant density tolerance and high yield potential,such as Jimai 22 and Liangxing 66,were recommended as leading cultivars for production as well as elite crossing parents for further increasing yield potential in the Yellow and Huai Valleys Winter Wheat Zone in China.
Yonggui XIAOJianjun LIUHaosheng LIXinyou CAOXianchun XIAZhonghu HE
OsDep1(dense and erectpanicle 1)控制水稻产量性状,影响穗长、直立性和着粒密度。根据水稻OsDep1基因序列,采用同源克隆技术克隆了普通小麦第5同源群染色体上的TaDep1基因,它包含5个外显子和4个内含子,与水稻OsDep1基因结构相似。TaDep1-A1、TaDep1-B1和TaDep1-D1的编码序列长度分别为918、888和900bp,编码305、295和299个氨基酸残基。在普通小麦品种中检测到5个TaDep1-A1等位变异、4个TaDep1-B1等位变异和2个TaDep1-D1等位变异。根据TaDep1-A1和TaDep1-B1位点不同等位变异间的SNP和InDel,开发了3对显性互补标记和1个共显性标记,可以准确鉴别不同等位基因。共显性标记dep19是根据TaDep1-B1第5外显子一个30bp的InDel开发的,可准确区分TaDep1-B1c与TaDep1-B1a、TaDep1-B1b和TaDep1-B1d。用这些标记对406份小麦品种进行检测,不同基因型的千粒重、株高、穗长、小穗数和穗节间均差异不显著。
