TITLE:
Identification of Genetically Distinct Cassava Clones from On-Farm Plantations to Widen the Thai Cassava Breeding Gene Pool
AUTHORS:
Preeya P. Wangsomnuk, Benjawan Ruttawat, Prapit Wongtiem
KEYWORDS:
Cassava; Distinctness; SSR; Ex Situ Conservation; Core Collection
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.8,
July
30,
2013
ABSTRACT: 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.