大豆重组自交系群体NJRISX豆腐和豆乳得率的QTL分析

QTL Mapping of Tofu and Soymilk Output in RIL Population NJRISX of Soybean

以176个家系组成的苏88-M21×新沂小黑豆重组自交系群体NJRISX为材料，通过MAPMAKER3．0构建了包含131个SSR标记、24个连锁群的遗传图谱，覆盖大豆基因组2044．6cM，标记平均间距15．6cM；经2005和2006两年试验，所获数据按主基因加多基因混合遗传模型分析干豆腐、湿豆腐和干豆乳得率的遗传机制；应用软件win QTL Cartographer Version2．5复合区间作图法（CIM）和多区间作图法（MIM）检测QTL。结果显示，在A2连锁群的Satt424-Sat_162区间检测到控制干豆腐和干豆乳得率的主效QTL各1个，qODT-A2-1可以解释15．7％-28．2％的表型变异，qODS-A2-1可以解释30．0％-34．8％的表型变异。检测到湿豆腐得率2个主效QTL，qOWT-A2-1位于A2连锁群的Satt424-Sat_162区间，可以解释20．7％-30．7％的表型变异，qOWT-L位于L连锁群的Satt481-Sat_397区间，可以解释19．0％-27．4％的表型变异。分离分析结果表明，干豆腐和干豆乳得率均属于1对主基因加多基因遗传，湿豆腐得率属于2对非连锁主基因加多基因遗传模型。上述QTL定位结果与分离分析所获的主基因数、贡献率及其和多基因的相对贡献可以相互验证，建议育种中要兼顾主基因和多基因的利用。

Genetic improvement of tofu and soymilk output is interested by both farmers and processors. The objective of the present study was to reveal the genetic system and map QTLs of tofu and soymilk output for improvement of the traits. The RIL population NJRISX consisting of 176 families was derived from a cross Su88-M21×Xinyixiaoheidou and was tested in two cropping years （2005 and 2006）. A genetic linkage map, containing 131 SSR markers, spanning 24 linkage groups （LG） at a total length of 2044.6 cM, with an average distance of 15.6 cM between the flanking markers was constructed by using MAPMAKER 3.0. Genetic analysis was performed under main gene plus polygene mixed inheritance model for the P1, P2, and RIL population and QTLs were mapped with both composite interval mapping （CIM） and multiple interval mapping （MINI） of the software Win QTL Cartographer Version 2.5 on output of dried tofu, wet tofu and dried soymilk. The main QTL qODT-A2-1 associated with dried tofu output, explaining 15.7%-28.2% of the total phenotypic variation was identified between Satt424 and Sat_162 on LG A2; the main QTL qODS-A2-1 related to dried soymilk output, explaining 30.0%-34.8% of the phenotypic variation was also between Satt424 and Sat_162 on LG A2; and two main QTLs qOWT-A2-1 and qOWT-L associated with wet tofu output, explaining 20.7%-30.7% and 19.0%-27.4% of the total phenotypic variation were identified between Satt424 and Sat_162 on LG A2 and between Satt481 and Sat_397 on LG L, respectively. The results from segregation analysis showed that dried tofu and soymilk output were dominated by one main gene plus polygenes and wet tofu output was by two unlinked main genes plus polygenes. In comparison, the number of main genes, the phenotypic variation proportion explained by the main genes, and the relative contri-bution of main gene vs. ploygene from both segregation analysis and QTL mapping were similar, and two genetic analyses could be used for verification each other. From described above, it was inferred that breeders for tofu and soymilk output should pay attention to both main genes and polygenes.