Evaluation of some walnut genotypes in the west of Iran using fruit characteristics and RAPD marker

Abstract

Persian walnut (Juglans regia L.) belongs to the family Juglandaceae is one of the most important nut crops in Iran. In this research, morphometric and genetic variations among some genotypes of Persian walnut collected from different parts of west Iran were evaluated based on nut characteristics and RAPD markers. In the first experiment, 29 traits related to nut and kernel were used to evaluate genetic potential of 119 walnut genotypes. The primary results of fruit morphometric characteristics showed that there is high variability in the some evaluated traits such as fruit shape, nut diameter and Kernel removal from nut in studied genotypes. Also, in the second experiment, the genetic diversity among 50 genotypes of walnut was evaluated using 13 RAPD markers. A total of 87 alleles were produced in the 13 RAPD markers with their sizes ranging from 140 to 2500 bp. The number of observed alleles for each locus ranged from 4 (OPA-18 and OPA-13) to 11 (OPA-09), with an average of 6.46 alleles per locus. Shannon's information index (I) value was observed to be highest (3.20) in the OPA-09 locus, while the OPA-13 locus had the lowest value (0.70) with an average of 1.66 among RAPD locus. The Jaccards’ genetic similarity coefficient ranged from 0.08 to 0.79 among genotypes. Finally, our results demonstrate some of these genotypes have been desirable traits and must be conserved as valuable genetic resources, from the perspective of breeding.

Keywords

• Cluster analysis
• Genetic resource
• RAPD
• Walnut