Micic Z, Hahn V, Bauer E, Melchinger A E, Knapp S J, Tang S, Schön C C
State Plant Breeding Institute (720), University of Hohenheim, Stuttgart, Germany.
Theor Appl Genet. 2005 Jul;111(2):233-42. doi: 10.1007/s00122-005-2004-x. Epub 2005 Jun 10.
Midstalk rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an important cause of yield loss in sunflower (Helianthus annuus L.). Objectives of this study were to: (1) estimate the number, genomic positions and genetic effects of quantitative trait loci (QTL) for resistance to midstalk rot in line TUB-5-3234, derived from an interspecific cross; (2) determine congruency of QTL between this line and other sources of resistance; and (3) make inferences about the efficiency of selective genotyping (SG) in detecting QTL conferring midstalk rot resistance in sunflower. Phenotypic data for three resistance (stem lesion, leaf lesion and speed of fungal growth) and two morphological (leaf length and leaf length with petiole) traits were obtained from 434 F3 families from cross CM625 (susceptible) x TUB-5-3234 (resistant) under artificial infection in field experiments across two environments. The SG was applied by choosing the 60 most resistant and the 60 most susceptible F3 families for stem lesion. For genotyping of the respective F2 plants, 78 simple sequence repeat markers were used. Genotypic variances were highly significant for all traits. Heritabilities and genotypic correlations between reMidstalk rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an important cause of yield loss in sunflower (Helianthus annuus L.). Objectives of this study were to: (1) estimate the number, genomic positions and genetic effects of quantitative trait loci (QTL) for resistance to midstalk rot in line TUB-5-3234, derived from an interspecific cross; (2) determine congruency of QTL between this line and other sources of resistance; and (3) make inferences about the efficiency of selective genotyping (SG) in detecting QTL conferring midstalk rot resistance in sunflower. Phenotypic data for three resistance (stem lesion, leaf lesion and speed of fungal growth) and two morphological (leaf length and leaf length with petiole) traits were obtained from 434 F3 families from cross CM625 (susceptible) x TUB-5-3234 (resistant) under artificial infection in field experiments across two environments. The SG was applied by choosing the 60 most resistant and the 60 most susceptible F3 families for stem lesion. For genotyping of the respective F2 plants, 78 simple sequence repeat markers were used. Genotypic variances were highly significant for all traits. Heritabilities and genotypic correlations between resistance traits were moderate to high. Three to four putative QTL were detected for each resistance trait explaining between 40.8% and 72.7% of the genotypic variance (PTS). Two QTL for stem lesion showed large genetic effects and corroborated earlier findings from the cross NDBLOSsel (resistant) x CM625 (susceptible). Our results suggest that SG can be efficiently used for QTL detection and the analysis of congruency for resistance genes across populations.
由核盘菌（Sclerotinia sclerotiorum (Lib.) de Bary）引起的向日葵茎腐病是向日葵（Helianthus annuus L.）产量损失的一个重要原因。本研究的目的是：（1）估计源自种间杂交的TUB-5-3234品系中抗茎腐病数量性状位点（QTL）的数量、基因组位置和遗传效应；（2）确定该品系与其他抗性来源之间QTL的一致性；（3）推断选择性基因分型（SG）在检测向日葵中赋予茎腐病抗性的QTL方面的效率。在两个环境下的田间试验中，通过人工接种，从CM625（感病）×TUB-5-3234（抗病）杂交组合的434个F3家系中获得了三个抗性性状（茎部病斑、叶片病斑和真菌生长速度）和两个形态性状（叶片长度和带叶柄叶片长度）的表型数据。通过选择60个茎部病斑抗性最强和最感病的F3家系来应用SG。对于相应F2植株的基因分型，使用了78个简单序列重复标记。所有性状的基因型方差都极显著。抗性性状之间的遗传力和基因型相关性为中等至高。每个抗性性状检测到3至4个假定的QTL，解释基因型变异（PTS）的40.8%至72.7%。两个茎部病斑QTL表现出较大的遗传效应，证实了之前NDBLOSsel（抗病）×CM625（感病）杂交组合的研究结果。我们的结果表明，SG可有效地用于QTL检测和群体间抗性基因一致性分析。
