Maturity Group Classification of Check Varieties in National Soybean Uniform Trials of China

Abstract

Maturity Group (MG) is a widely-used system for soybean varieties classification in the world. However, it has not been adopted yet in China. In the current studies, we identified the MG catagories for 19 check varieties from the National Soybean Uniform Trials of China by comparing the check varieties with 38 MG standard varieties from the North America, which covered MG000–MGVIII. The check varieties from 16 trial groups represented most of the released soybean varieties in China.All standard and check varieties were sown in spring of Beijing and Wuhan, and the supplementary tests using local varieties were conducted in other 18 sites across the country. The results showed that the MGs of check varieties in the National Soybean Uniform Trials ranged from MG0 to MGVI. Some varieties from different trial groups could be classified into the same MGs, for example, MGIII included the varieties from the Late Group of the Northern Spring Planting Soybean Region, Northwest Spring Planting Soybean Region, all three (north, mid and south) zones of Huanghuaihai Summer Planting Soybean Region, and Southwest Mountainous Spring Planting Soybean Region; the varieties from Yangtze River Spring Planting Soybean Region and the Tropical and Subtropical Summer Planting Soybean Regions were classified into MGV and MGVI. Fudou 301 and Quandou 7,check vrieties from the Tropical and Subtropical Spring Planting Soybean Regions, belonged to MGII and MGIV, respectively.Based on the MG classification and other factors, the authors suggested that the Huanghuaihai Summer Planting Soybean Region can be changed to two (north and south) zones from the current three (north, mid, and south) zones, and the regionization of National Soybean Uniform trials in South China should also be modified. Late Maturity Group of the Northern Spring Planting Soybean Region and the Northwest Spring Planting Soybean Region, both belong to MGIII, should be separated because they are different ecotypes in drought tolerance. The results of this experiment pave the way for establishing the MG system based on biological identities of varieties in order to classify soybean varieties and regionalize the soybean production regions in China.