Soybean breeding for rust resistance in Thailand and extent of rust resistant cultivars used

Soybean is one of the important economic crops in Thailand. Soybean rust (Phakopsora pachyrhizi Syd.) which caused economic losses is considered as one of the major diseases. Breeding for soybean rust resistance has been one of the main objectives of soybean breeding programs. Since 1970, conventional breeding, mutation techniques and DNA marker assisted selection for rust resistance have been carried out for soybean breeding program in the kingdom. The tolerant varieties, SJ4, SJ5, Chiang Mai 60 (CM60) and Doi Kham are recommended to grow in soybean producing areas. In the part of Plant Pathology, the update research results indicated that there were eight races of rust in the North of the country. The new promising resistant lines, CM60-10kr-71 and MJ 9519-5 resisted to those eight races. (Reddish Brown Type), while MJ 9518-5 resisted to only seven races and susceptible to the race SM-44-1 (Tan Type). At the present time, the molecular biology has been used to facilitate the breeding program. It was found that two markers (Satt 12 and Satt 472) were associated with soybean rust resistance. Marker assisted selection will be used to select soybean rust resistant lines.