Abstract: 【Objective】The contents of folic acid in foxtail millet originated from different regions in Shanxi was analyzed to evaluate the relationship between the variation of folic acid content and ecological distribution in Shanxi, and provide supports for identification of millet quality and breeding.【Method】Totally 245 traditional millet varieties for breeding and planting in Changzhi, Fenyang and Taiyuan were collected, respectively, to determine folic acid content by indirect fluorescent method. The millet seeds were dried at 60℃ after recording the hull colour, and peeled by grinding, and then the color seed grains were marked, and sieved through 100 meshes. Folic acid was extracted by potassium dihydrogen phosphate in waterbath. To obtain the optimum extraction effect, the active carbon adsorbent treated by aniline was added to extraction, the extracts were eluted continuously with a mixture containing 3% ammonia and 70% ethanol, and indirect fluorescent method was used to determine the fluorescence intensity of folic acid oxidized by potassium permanganate.【Result】 The average content of folic acid in millets from Shanxi was 1.53 μg•g-1. Folic acid content in millets exhibited a normal distribution characteristic with the left deviation, indicating that the contents of folic acid in millets were gathered at higher level relative to average. Folic acid content in different regions showed a significant difference. The same variety grown in Fenyang showed the lowest folic acid content compared to that in Taiyuan and Changzhi. Data showed that daily mean temperature, sunshine time and relative humidity had no significant effects on the folic acid content, the rainfall affected significantly the contents of folic acid. The seed colour had no significant impact on folic acid content, but the color of peeled millet grains remarkably affected the contents of folic acid. The millet grains with brown and green color had the highest contents of folic acid, and the grains with yellow, canary yellow, pale yellow and white color were decreased in turn.【Conclusion】It was concluded that folic acid content in foxtail millet germplasms exhibited wide genetic diversity, some foxtail millet varieties with higher folic acid content were identified, thus providing valuable material supports for breeding with high quality and germplasm innovation. The variation range was determined between 0.37 and 2.37 μg•g-1 and the variation coefficient r was 26.2%. Folic acid contents in different ecological regions displayed a significant difference, and the contents of folic acid in millets from late maturing areas were significantly higher than that in mid-maturing areas for spring sowing millets. The color of millet grain significantly affected folic acid content. In this study, total 24 foxtail millet varieties with higher folic acid content were identified, and they accounted for 9.8% of all the tested materials based on the content distribution of folic acid. Among them, Jingu 21, as a major leading cultivar in agricultural production, should be widely extended in Shanxi province, because it is a cultivated variety with higher folic acid content, and the folic acid content in millet variety Jingu 21 reaches 2 μg•g-1.

Key words: Shanxi province , millet , germplasm resource , ecology type , seed color , folic acid content