Synteny between bulb onion and bunching onion based on linkage maps.

已经建立了鳞茎洋葱（Allium cepa L.）和束状洋葱（A.）的连锁图谱。fistulosum l .)。由于这两个物种同属Cepa科，染色体数目相同（2n=16），因此可以认为它们之间存在高水平的宏观同步。然而，由于这两个物种的地图上很少有共同的标记，因此没有进行详细的比较。本研究的目的是在全基因组水平上评价束状洋葱和鳞茎洋葱的一致性。首先，我们在F_2群体中建立了黄鳞茎葱与红葱的基础连锁图谱。连锁图谱包括11个连锁组，164个标记，覆盖1040 cM。在8条染色体上分配10个连锁组，共65个标记。虽然两个SNP标记（F3' H和DFR）都位于Chr. 7上，但两个性状标记Pg和Ant1与DFR密切相关。在Chr 7上也检测到一个球茎色素沉着的QTL。所有DFR位点洋葱等位基因纯合的F_2个体均无色素沉着。在F_2和F_<2∶3>的DFR位点上，替换了小葱等位基因后，红色色素沉着程度显著变暗。因此，DFR是影响该群体球茎颜色的关键基因之一。

Linkage maps have been developed for bulb onion(Allium cepa L.) and bunching onion(A. fistulosum L.). It is considered that a high level of macrosynteny exists between these 2 species since they belong to the section Cepa and have the same chromosome number(2n=16). However, a detail comparison has not evaluated because there are few common markers onto the maps of both species. The objective of this study was to evaluate synteny at the genome-wide level between bunching onion and bulb onion. As a first step, we developed a basal linkage map in F_2 population between yellow bulb onion and red shallot. Linkage map consists of 11 linkage groups with 164 markers covering 1, 040 cM. Ten linkage groups were assigned to eight chromosomes with 65 markers. Although both SNP markers(F3' H and DFR) were located on the Chr. 7, two trait markers, Pg and Ant1, were closely linked to DFR. A QTL for bulb pigmentation was also detected on the Chr. 7.All individuals homozygous for onion allele at DFR loci showed no pigmentation in F_2 individuals. The degree of red pigmentation became significantly darkened by replacing shallot allele at DFR in both F_2 and F_<2 : 3>. Therefore, DFR is one of key genes involved in bulb color in this population.