Abstract: Abstract 【Objective】The present paper was aimed to evaluate the variability of content of fat and major fatty acids (hereafter referred as fat-related traits) in cultivated and wild soybean germplasm in China and to screen for accessions superior in fat-related traits so as to provide materials and guidelines in the improvement of fat-related traits in various eco-regions. 【Methods】The cultivated and wild soybean germplasms from various eco-regions[10] were sampled, tested, and analyzed for their fat-related traits. Based on single trait analyses, multivariate index, principal component analysis and cluster analysis were carried out to investigate the comprehensive variability of all fat-related traits in cultivated and wild soybeans from various eco-regions. 【Results】The results were as follows: (1) The average fat content of cultivated soybean in whole country was 17.21%, 6.22% higher than that of wild soybean; that of oleic was 23.25%, 7.75% higher than the wild; that of linoleic acid was 53.53%, 2.57% lower than the wild; and that of linolenic acid was 8.00%, 4.23% less than the wild; however, the variability of the fat-related traits in cultivated soybean was smaller than those in wild soybean. A similar tendency was observed in various eco-regions. As for the saturated fatty acids, there showed no large difference between the two species in whole country as well as in various eco-regions. (2)The multivariate variability in wild soybean was larger than that in cultivated soybean in whole country as well as in various eco-regions. The long term artificial selection reduced the variability, but made a wider direction of variation in cultivated soybean. (3) There showed a significant positive correlation between fat content and source latitude of accessions in cultivated soybean, but not in wild soybean, indicating the correlation in cultivated soybean was mainly due to artificial selection for fat content in the history. (4) Elite accessions with high fat content, high oleic acid content, high linoleic acid, low linolenic acid were screened out, respectively. Among them, N23547 and N23697 were the best with high fat content more than 23%, oleic acid more than 30% and linolenic acid less than 5%.【Conclusions】 The average contents of fat and oleic acid of cultivated soybean were significantly higher than, the average content of linolenic acid was significantly lower than, and the average content of linoleic acid was a little lower than that of the wild soybean, while no large difference in saturated fatty acids between the two species in China. Large variation of fat-related traits existed within all the eco-regions in the two species, even larger than those among eco-regions. The significant correlation between fat content and source latitude was mainly due to the long term artificial selection for fat content in the history.

Key words: Glycine max (L.) Merr., Glycine soja Sieb. et Zucc., Germplasm resources, Fat content, Fatty acid components, Variability