控制甜瓜雄花分化基因的遗传分析及初步定位

利用甜瓜全雌系WI998(无雄花)与雌雄异花同株品系3-2-2(有雄花)杂交,F1代全部表现为雌雄异花同株(有雄花)。F2代群体分离比率有雄花:无雄花为3:1。F1代作父本与全雌系WI998(无雄花)回交,群体分离比率有雄花:无雄花为1:1;F1代作父本与雌雄异花同株品系3-2-2(有雄花)回交,群体全部表现为有雄花。结果表明,控制甜瓜雄花分化的基因为一对显性基因,命名为An。同时以F2代分离群体为试材,采用SSR分子标记初步构建了甜瓜的遗传图谱,定位了控制甜瓜雄花分化基因(An)。图谱由5个连锁群组成,包括18个SSR标记,1个形态学标记,覆盖基因组总长度442.7 cM,标记间平均距离为24.6 cM。初步将控制甜瓜雄花分化基因(An)定位在第2连锁群上,其两侧标记分别是MU4182-2和MU5028-1,与An的间距分别为42.8和26.0 cM。控制甜瓜雄花分化基因的发现进一步完善了甜瓜性别分化基因的表达机理。

Genetic analysis of controlling staminate expression gene and preliminary mapping of melon

The gynoecious melon(Cucumis melo L.)line WI998(absence staminate) was crossed as female parent with the monoecious melon line 3-2-2(presence staminate).The F1 generation was all monoecious.The ratio of sex expression on F2 generation of the crossing segregated was 3: 1(presence staminate: absence staminate).The F1 was backcrossed as male parent to WI998,and the ratio of sex expression on BC1P1 generation segregated was 1: 1(presence staminate: absence staminate).Whereas the F1 was as male parent backcrossed to 3-2-2,and the ratio of sex expression on BC1P2 generation was all presence staminate.The results showed that a dominant gene control the differentiation of staminate flowers on melon.The gene was named as An.The F2 population was used to construct the map of melon and to map the An gene by using simple sequence repeat(SSR) markers in this research.The genetic map consisted of five linkage groups,contained 18 SSR markers and one morphological marker.It spanned total of 442.7 cM genetic distance with a 24.6 cM average interval.Two SSR markers,MU4182-2 and MU5028-1 were mapped near the An gene.Linkage analysis indicated that the An gene was located on the linkage group 2.These markers distance of An gene were 42.8 and 26.0 cM,respectively.The founding of An gene of controlling presence staminate on melon will be having great foundati on onresearch of sex expression genes and their working principle on cucurbit.