大豆脂肪及脂肪酸组分含量的QTL定位

脂肪及脂肪酸组分的改良是大豆油脂品质育种的主要方面。本研究旨在构建遗传图谱，定位大豆脂肪及脂肪酸组分的QTL，为大豆油脂品质育种提供参考。以Essex×ZDD2315的114个BC₁F₁单株为作图群体，构建了250个SSR标记和1个形态标记，具有25个连锁群的遗传图谱，覆盖大豆基因组2 963.5 cM，平均每个连锁群上10.0个标记，标记平均间距11.8 cM。用BC₁F₃家系3个重复的表型平均值代表相对应的BC₁F₁单株表型值，采用Win QTL Cartographer 2.5复合区间作图法（CIM）检测到18个控制脂肪及脂肪酸组分含量的QTL，位于9个不同的连锁群上，表型贡献率为9.6%~34.5%；多区间作图法（MIM）检测到与CIM区间相同的7个QTL（fat-1, pal-1, st-1, ole-1, lin-1, lin-4和lio-2），区间相近的2个QTL（ole-4和lin-5），位于6个不同的连锁群上，表型贡献率为8.2%~39.3%。CIM法检测到的其他9个QTL有待进一步验证。大豆脂肪及脂肪酸组分含量的主效QTL数量不多，效应大的不多，可能还受许多未能检测出来的微效基因控制，育种中既要注意主效QTL的利用，又要考虑微效多基因的积聚。

QTL Mapping for Fat and Fatty Acid Composition Contents in Soybean

Genetic improvement of fat and fatty acid composition content of soybean seed is interesting to both farmers and processors. The objective of the present study was to aim at constructing a genetic linkage map and mapping QTLs conferring fat and fatty acid composition contents in soybean. The mapping population with 114 BC1F1 plants of the soybean backcross (Essex×ZDD2315)×ZDD2315 was established and tested for their genetic variation, and then used to construct a genetic linkage map by using MAPMAKER 3.0. The genetic linkage map contained 250 SSR markers and one morphological marker, spanning 25 linkage groups (LG) at a total distance of 2 963.5 cM. Each LG contained 2 to 20 markers, with average distance being about 11.8 cM. The methods of composite interval mapping (CIM) and multiple interval mapping (MIM) of Win QTL Cartographer Version 2.5 were used for QTL mapping. With CIM, 18 QTLs conferring the contents of fat and fatty acid composition in soybean seed were mapped on nine LGs, i.e. B2, C1, D1b-1, D2, E, H-1, I, L and N-1, explaining 8.2%–39.3% of the total phenotypic variation, while with MIM nine QTLs were detected on six LGs, i.e. B2, C1, D1b-1, D2, H-1 and N-1, explaining 9.6%–34.5% of the total phenotypic variation. Of which seven QTLs, i.e. fat-1, pal-1, st-1, ole-1, lin-1, lin-4 and lio-2, were located on the same regions as that under CIM, while the other two, i.e. ole-4 and lin-5, were close to those under CIM. The other nine QTLs detected with CIM, but not common with MIM, need to be further verified. The number of major QTLs with large effect conferring the contents of fat and fatty acids appeared not as many as expected, while the minor QTLs with small effect accounted for a certain amount of the variation. Therefore, both major and minor QTLs should be considered in the improvement of fat quantity and quality in soybean seeds.