GENETIC DIVERSITY IN ANCHOTE (Coccinia abyssinica (Lam.) Cogn) USING MICROSATELLITE MARKERS

Abstract

Anchote (Coccinia abyssinica (Lam.) Cogn) is an endemic crop species of Ethiopian origin mainly cultivated for its nutritious tuberous roots and tender leaves. Limited molecular marker resources hinder breeding and genetic studies for improvement, conservation and management of anchote genetic resources. The use of cross-species/genera transferable SSR markers is considered cost-effective strategy to ensure availability of markers in genetically understudied crops such as anchote. In this study we aimed to assess cross-transferability of cucurbit SSR markers to C. abyssinica and measure the genetic diversity of anchote and of its populations; across the cultivation range in Ethiopia. A total of 102 SSR primer pairs from cucurbit species were screened for transferability to anchote and polymorphic SSRs were identified. A total of 45 germplasm accessions collected from Western parts of Ethiopia were studied along with three cultivars of related species in Cucurbitaceae family using the polymorphic microsatellite markers. Out of 102 screened SSR primer pairs 46 (45.1%) were found transferable as they amplified scrabble band on anchote; of which only 24 primers pairs (23.5%) amplified polymorphic loci. Most of (53.6 %) of the SSR markers were transferred to anchote from Cucumis sativus L. All the analyzed 24 loci were highly polymorphic and detected a total of 354 alleles among all population, with an average of 15 alleles per locus. In the total germplasm collection the average genetic diversity, as quantified by the expected heterozygosity, was 0.88±0.06 per locus. Nei’s gene diversity index revealed that the genetic diversity of East Wellega anchote maintained in situ in the farmers’ field and ex situ in the DZARC gene bank was comparable, and retained the highest (I = 1.93) of all populations. Using discriminant analysis of principal components (DAPC), four clusters including outlier groups were detected. The DAPC analysis indicated that the most closely related populations were geographically occurred in closer proximity to each other. AMOVA attributed 95% of genetic variation to within population and only 5% to between populations. The results provide important genetic information in C. abyssinica to drive improvement, management and conservation decisions efforts. Analysis of genome wide functional factors and evaluation of agromorphological traits in additional germplasm set including wild anchote and other Coccina genetic resources would add necessary genetic information for improvement of the crop.