摘要
Cassava (Manihot esculenta Crantz) is one of the most important economic crops in Thailand. However, the Thai cassava breeding gene pool was genetically narrow with only 11 distinct landraces. An attempt was made here to characterize 266 cassava clones collected from 80 farms in eight provinces using 35 SSR markers. A total of 365 polymorphic alleles were detected in the assayed samples. The molecular analysis of variance revealed that a large SSR variance (19.8%) was present among the farm samples. The genetic relationships of the 266 farm samples revealed by the principal coordinate analysis confirmed the large SSR variation observed among the collected cassava samples. The average dissimilarity (AD) of a cassava sample against the other 265 samples was calculated and the AD values obtained ranged from 0.256 to 0.502 with a mean of 0.319. Based on these AD values, a set of 50 unique cassava samples with AD values of 0.346 or higher was assembled from the on-farm samples to widen the genetic base of the Thai cassava breeding gene pool.
Cassava (Manihot esculenta Crantz) is one of the most important economic crops in Thailand. However, the Thai cassava breeding gene pool was genetically narrow with only 11 distinct landraces. An attempt was made here to characterize 266 cassava clones collected from 80 farms in eight provinces using 35 SSR markers. A total of 365 polymorphic alleles were detected in the assayed samples. The molecular analysis of variance revealed that a large SSR variance (19.8%) was present among the farm samples. The genetic relationships of the 266 farm samples revealed by the principal coordinate analysis confirmed the large SSR variation observed among the collected cassava samples. The average dissimilarity (AD) of a cassava sample against the other 265 samples was calculated and the AD values obtained ranged from 0.256 to 0.502 with a mean of 0.319. Based on these AD values, a set of 50 unique cassava samples with AD values of 0.346 or higher was assembled from the on-farm samples to widen the genetic base of the Thai cassava breeding gene pool.
