Intra-specific genetic diversity in water yam (Dioscorea alata L.) accessions collected from Myanmar, Papua New Guinea and Japan
2018
Olu-Olusegun, F. | Babil, P. | Kikuno, H. | Irie, K. | Toyohara, H. | Shiwachi, H.
Understanding germplasm diversity is valuable in improving underutilized water yam (Dioscorea alata L.) diversity. In this study, we investigated intra-specific genetic diversity based on morphological traits, SSR polymorphisms and ploidy levels in water yam accessions collected from Myanmar, Papua New Guinea (PNG)and Japan. The results of agro-morphological analysis showed that the distance between leaf lobes, petiole color, and wrinkles on the tuber surface strongly contributed to grouping. Furthermore, SSR polymorphisms were observed in all 12 microsatellite loci analyzed, revealing a mean polymorphic information content of 0.63, with total of 58 alleles detected. Analysis of molecular variance indicated 98% variation within populations and 2% among populations. Meanwhile, ploidy analysis revealed three ploidy levels:29 diploids (2n = 40), 8 triploids (2n = 60) and 4 tetraploids (2n = 80). Notably, only diploids were observed among accessions from Japan. In all three levels of analysis, no association with geographical origin was observed. Moreover, intra-specific diversity from each origin was relatively close, except during ploidy analysis. These findings suggest, for the first time, that accessions from Japan are as diverse as those from Myanmar and PNG.
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