西瓜遗传图谱构建及其强雌性状定位研究

Linkage mapping in watermelon population segregation for subgynoecious trait

以雌花率稳定在80%以上的强雌性品系BG1(Citrullus lanatus var.lanatus)和普通花性型非洲野生西瓜900134(C.lanatus var.citroides)为亲本杂交自交获得F2群体,通过AFLP、RAPD及SSR技术对该群体进行扩增,建立了一个包括4个RAPD标记、140个AFLP标记、6个SSR标记和1个强雌性位点(subgy)的遗传图谱。该图谱包含17个连锁群,覆盖基因组1073.1cM,标记间平均图距为7.2cM。subgy定位在第5连锁群中,与s1454-1100、GT-CTA270两个标记连锁,距离分别为5.8cM和14.3cM。将特异条带s1454-1100回收、克隆、测序,设计特异SCAR引物,再对F2单株基因组DNA扩增,只在大部分的纯合强雌性单株和杂合普通花性型单株中扩增出一条375bp的特异带,以JoinMap3.0软件分析,该标记与与强雌性状位点的连锁距离为6.1cM,连锁较为紧密,表明已成功地将与西瓜强雌性连锁的标记转化为操作简便、表现稳定的SCAR标记,命名为SR375。

RAPD,AFLP and SSR markers were used to generate a linkage map in an F2 population derived from a cross between the subgunoecious line BG1 （female flower proportion above 80%）and normal sexual line 900134 （Afriacan wild germplasm,female flower proportion about 10% to 20%）. A linkage map covering 1 073.1 cM with a mean marker interval of 7.2 cM was constructed. 4 RAPD,140 AFLP,6 SSR markers and a subgy （subgynoecious trait）spanned 17 linkage groups. The location of subgy was defined in the linkage group 5 by genetic linkage and analysis to be associated with RAPD locus s1454-1100 and AFLP locus GT-CTA270 at 5.8 cM and 14.3 cM,respectively. The band s1454-1100 was collected and sequcenced to synthesis a sequence-characterized amplified region （SCAR）primer,which was used to amplify the individual DNA of the F2 population and obtained a special band of 375 bp in the most of homozygous subgynoecioius individuals and heterozygous normal sexual individuals. The genetic distance between this band and subgy was 6.1 cM by linkage analysis using the software Jionmap 3.0. The result indicated that a successful conversion of the SCAR marker from RAPD. This SCAR marker was designed as SR375. It will contribute to the further study and breeding for subgynoecioius in watermelon.