Abstract: 【OBJECTIVE】Breeding for output and quality of tofu and soymilk in soybeans is highly concerned recently by the related industry. The objective of the present study was aimed at revealing the inheritance and QTL mapping of tofu and soymilk output for genetic improvement of the traits.【METHOD】Segregation analysis for tofu and soymilk output in two cropping years (2004 and 2005) were conducted by using a RIL population with 184 lines derived from Kefeng No.1×Nannong 1138-2 under the Major Gene Plus Polygene Mixed Inheritance Model according to Gai et al. (2003). Based on a genetic linkage map, spanned 3416.20 cM with 488 markers in 25 linkage groups, constructed from the RIL population, QTLs of tofu and soymilk output were mapped by using the composite interval mapping (CIM) procedure of the software Cartographer V. 2.5 according to Wang et al.(2001-2004).【RESULTS】The results from segregation analysis showed that tofu output was controlled by two linked major genes (recombination value 0.00) plus polygenes, with the major gene heritability of 13.23%~26.84%, and polygene heritability of 73.15%~86.77%; soymilk output was controlled also by two linked major genes (recombination value 0.00) plus polygenes, with the major gene heritability of 17.27%~22.29%, and polygene heritability of 77.71%~82.73%. The results of QTL mapping showed that two linked QTLs associated with tofu output between STAS815T and A676I on the linkage group C2 were identified with CIM, explaining 16.23%~23.18% of the total phenotypic variation, and a QTL related with soymilk output in the interval of satt728~K24I on the linkage group M was identified, explaining 4.73%~ 7.14% of the total phenotypic variation.【CONCLUSION】Both tofu and soymilk output in soybean were controlled under major genes with smaller heritability and polygenes with heritability more than 73.15% so that accumulating polygenes should be emphasized in the improvement of tofu and soymilk output. The results between segregation analysis and QTL mapping appeared somewhat consistent, therefore could be used for verification each other.

Key words: Tofu, Soymilk, Recombinant inbred lines (RILs), QTL mapping