Abstract
The utility of seventeen Microsatellite (SSR) markers and fifteen inter simple sequence repeats (ISSR) markers for the identification of twenty eight ramets of 11 varieties of walnut (Juglans regia) was explored. Thirty nine individual genomes were screened using 61 and 38 scorable fragments from SSR and ISSR markers, respectively. The least polymorphic SSR locus was WGA004 (two alleles) and the most polymorphic (5 alleles) was WGA276. Polymorphism information content values ranged from 0.08 (WGA004) to 0.43 (WGA032) in SSR markers and from 0.11 (AGA (AC)7) to 0.49 (CAC(TGT)5) in ISSR markers, with an average of 0.29 and 0.19, respectively. In most cases, grafted varieties with identical names also had the same microsatellites profile. The principal coordinate analysis and clustering (UPGMA) based on the combined marker set emphasized two failures in grafting or off-types, ramets identified as Serr 4 (S4) and Vina 1 (V1). The presence of two off-type ramets in the walnut research orchard emphasizes the importance of using molecular certification for proving true-to-type of walnut orchards. Using 13 polymorphic SSRs, we tabulated a DNA fingerprint chart of 11 walnut varieties. Except for ‘Chandler’, each cultivar could be distinguished using a combination of only two SSR loci. The 13 SSRs markers evaluated in this study could be used in future to identify clones produced from the varieties.
Role of kaolin on drought tolerance and nut quality of Persian walnut
