Chaerani R, Smulders M J M, van der Linden C G, Vosman B, Stam P, Voorrips R E
Plant Research International, P.O. Box 16, 6700 AA, Wageningen, The Netherlands.
Theor Appl Genet. 2007 Feb;114(3):439-50. doi: 10.1007/s00122-006-0442-8. Epub 2006 Nov 9.
Alternaria solani (Ellis and Martin) Sorauer, the causal agent of early blight (EB) disease, infects aerial parts of tomato at both seedling and adult plant stages. Resistant cultivars would facilitate a sustainable EB management. EB resistance is a quantitatively expressed character, a fact that has hampered effective breeding. In order to identify and estimate the effect of genes conditioning resistance to EB, a quantitative trait loci (QTL) mapping study was performed in F2 and F3 populations derived from the cross between the susceptible Solanum lycopersicum (syn. Lycopersicon esculentum) cv. 'Solentos' and the resistant Solanum arcanum (syn. Lycopersicon peruvianum) LA2157 and genotyped with AFLP, microsatellite and SNP markers. Two evaluation criteria of resistance were used: measurements of EB lesion growth on the F2 plants in glasshouse tests and visual ratings of EB severity on foliage of the F3 lines in a field test. A total of six QTL regions were mapped on chromosomes 1, 2, 5-7, and 9 with LOD scores ranging from 3.4 to 17.5. Three EB QTL also confer resistance to stem lesions in the field, which has not been reported before. All QTL displayed significant additive gene action; in some cases a dominance effect was found. Additive x additive epistatic interactions were detected between one pair of QTL. For two QTL, the susceptible parent contributed resistance alleles to both EB and stem lesion resistance. Three of the QTL showed an effect in all tests despite methodological and environmental differences.
链格孢（Alternaria solani (Ellis and Martin) Sorauer）是早疫病（EB）的致病因子，在幼苗期和成株期均可侵染番茄地上部分。抗性品种有助于实现早疫病的可持续管理。早疫病抗性是一种数量性状，这一事实阻碍了有效的育种工作。为了鉴定和评估调控早疫病抗性的基因效应，在由感病的栽培番茄（Solanum lycopersicum，同义词Lycopersicon esculentum）品种‘Solentos’与抗病的秘鲁番茄（Solanum arcanum，同义词Lycopersicon peruvianum）LA2157杂交产生的F2和F3群体中进行了数量性状位点（QTL）定位研究，并用AFLP、微卫星和SNP标记进行基因分型。使用了两种抗性评估标准：在温室试验中测量F2植株上早疫病病斑的生长情况，以及在田间试验中对F3株系叶片上早疫病严重程度进行视觉评级。共在1、2、5 - 7和9号染色体上定位到6个QTL区域，LOD值范围为3.4至17.5。三个早疫病QTL在田间也赋予了对茎部病斑的抗性，这在以前尚未见报道。所有QTL均表现出显著的加性基因作用；在某些情况下还发现了显性效应。在一对QTL之间检测到加性×加性上位性互作。对于两个QTL，感病亲本对早疫病和茎部病斑抗性均贡献了抗性等位基因。尽管存在方法和环境差异，其中三个QTL在所有试验中均表现出效应。
