Genetic diversity of taro, Colocasia esculenta (L.) Schott, in Southeast Asia and the Pacific

Abstract

The genetic diversity of 255 taro (Colocasia esculenta) accessions from Vietnam, Thailand, Malaysia,Indonesia, the Philippines, Papua New Guinea and Vanuatu was studied using AFLPs. Three AFLP primer combinations generated a total of 465 scorable amplification products. The 255 accessions were grouped according to their country of origin, to their ploidy level (diploid or triploid) and to their habitat--cultivated or wild. Gene diversity within these groups and the genetic distance between these groups were computed. Dendrograms were constructed using UPGMA cluster analysis. In each country, the gene diversity within the groups of wild genotypes was the highest compared to the diploid and triploid cultivars groups. The highest gene diversity was observed for the wild group from Thailand (0.19), the lowest for the diploid cultivars group from Thailand(0.007). In Malaysia there was hardly any difference between the gene diversity of the cultivars and wild groups, 0.07 and 0.08, respectively. The genetic distances between the diploid cultivars groups ranges from 0.02 to 0.10, with the distance between the diploid accessions from Thailand and Malaysia being the highest. The genetic distances between the wild groups range from 0.05 to 0.07. First, a dendrogram was constructed with only the diploids cultivars from all countries. The accessions formed clusters largely according to the country from which they originated. Two major groups of clusters were revealed, one group assembling accessions from Asian countries and the other assembling accessions from the Pacific. Surprisingly, the group of diploid cultivars from Thailand clustered among the Pacific countries. Secondly,a dendrogram was constructed with diploid cultivated,triploid cultivated and wild accessions. Again the division of the accessions into an Asian and a Pacific gene pool is obvious. The presence of two gene pools for cultivated diploid taro has major implications for the breeding and conservation of germplasm.

Genetic structure and diversity of East African taro [Colocasia esculenta (L.) Schott]

“…This agrees well with report of Kreike et al (2004) and Mace et al (2006). This may be attributed to the limited number of taro accessions introduced to populations.…”

Screening for Drought Tolerance in Thirty Three Taro Cultivars

“…Ploidy data were obtained for 12 of the studied cultivars (Table 1) (Kreike et al, 2004;Traore, 2013). A correlation was found between STI and available ploidy levels (data not shown), indicating that in taro triploids can in fact have an advantage in yield and yield stability under drought.…”

“…Before the drought assay (2012)(2013), plants of all cultivars were multiplied, acclimatized and maintained in the experimental greenhouses. Ploidy levels of the studied varieties (whenever available) were obtained from Traoré (2013) and Kreike et al (2004).…”

On the origin of sweet potato (Ipomoea batatas (L.) Lam.) genetic diversity in New Guinea, a secondary centre of diversity

“…In the past decade, molecular markers have shown their potential to investigate origins of Pacific crops (Lebot, 1999;Kreike et al, 2004;Clarke et al, 2006, Hinkle, 2007Gunn et al, 2011;Perrier et al, 2011), complementing archaeological and anthropological data. Molecular markers have already been used to analyse the genetic base of sweet potato from Oceania and New Guinea (Zhang et al, 1998;Gichuki et al, 2003;Zhang et al, 2004), but studies thus far have used relatively small samples (fewer than 150 accessions).…”