A New Glycine soja Germplasm Accession with Green Seed-coat Color

Abstract

Wild soybean (Glycine soja) is a useful genetic resource for broadening the genetic background of cultivated soybean. We selected a wild type soybean line showing a unique character consisting of a green seed-coat color at Yeongchun in Korea 1996 and designated it as KLG10084. The objectives of the present study were as follows; (1) to evaluate the agronomic characters of KLG10084 by comparing them to those of other wild-type accessions and cultivars, and (2) to evaluate the possibility of improving the seed-coat color in an interspecific cross of G. max ×G. soja. The major agronomic traits of KLG10084 were investigated and a genetic relationship was analyzed by comparing it to wild soybean (G. soja) and soybean cultivars (G. max) using the RAPD technique. KLG10084 was similar to IT184256, one of the G. soja accessions tested, that was known as a wild soybean exhibiting typical wild-type characters in stem diameter, pod size at maturity, seed size, hard seed and viny growth habit. A cluster analysis using UPGMA suggested that KLG10084 belonged to the group of wild soybean. It strongly indicated that the KLG10084 line corresponded to an accession of G. soja showing a green seed-coat color, based on morphological and RAPD analysis. The populations were generated by crossing KLG10084 with two different G. max cultivars, ‘Sobaegnamulkong’ and ‘Eunhakong’, and backcrossing it to the G. max parent to obtain BC₀ to BC₃ populations. The seed-coat color was evaluated on the populations representing each generation. The percentage of acceptable seed-coat color was 74% in the BC₀F₂, 90% in the BC₁F₂ and 97% in the BC₂F₂ generations, and approximately 100% in the BC₃F₂ generation in the population of Eunhakong × KLG10084. These results indicated that a single backcross is required to recover a commercially desirable seed-coat color in a population derived from an interspecific cross of G. max × G. soja when KLG10084 is used as a G. soja parent. Therefore, KLG10084 was considered to be a valuable gene source in overcoming the seed-coat color in interspecific crosses and was particularly useful for shortening soybean breeding programs by reducing the number of backcrosses that are required.