Characterization and evaluation of Grapes (Vitis vinifera L. ) diversity in Potohar region of Pakistan.

Abstract

Grape (Vitis Vinifera L.) belongs to family Vitaceae and is one of the top ranked fruit of world. It has a rich amount of genetic diversity. According to an estimate there are more than 10,000 cultivars of grapes that exist in nature. It is a highly nutritious fruit and has countless health benefits. However, in our country it is grown as a minor fruit and its production is too low to meet the demand for people. High quality grapes production is achieved in the world through morphological, biochemical and genetic characterization but little effort has been made in Pakistan to characterize grapes. Characterization of grapes is of great concern to estimate diversity and is a step forward toward effective and efficient use of germplasm. Potohar is one of the neglected areas which is rich in grapes diversity. The present study was planned to characterize local and exotic genotypes present in Potohar, Pakistan on the base of morphological, biochemical and genetic characteristics. In morphological qualitative characterization, 44 qualitative traits were selected from IPGRI descriptor. These morphological traits performed a significant role in analyzing grape diversity but the major traits that discriminate the genotypes included mature leaf variables (ML: DPHMV, ML: DPHMV, ML: DEHMV) and young leaf variables (YL: DPHBV, YL: DPHMV and YL: DEHMV). PCA grouped all genotypes on the base of their phenotypic relation and cluster analysis divided the genotypes in to three main classes. Genotypes in each class were similar on the basis of morphological characteristics. Regarding grape quantitative traits, great differences were observed in bunch and berry characteristics (length, width and weight). Local genotypes were more prominent in these characteristics while exotic genotypes Regenia, Perlet and Early White were evaluated as early mature genotypes to prevent berry rot at maturity due to monsoon rains in Potohar, Pakistan. Biochemical analysis indicated notable variations among the genotypes in all quantitative parameters of sugars (sucrose, glucose, fructose, mannose, ribose and xylose), enzymes (SOD, POD, CAT) and in phenolic components. In sugars, reducing sugars, xylose, total sugars and ribose played their contributory role in discriminating genotypes. SOD, POD and CAT had positive correlation in genotypes Gola, Gol, Chakwal Selection, Chesslas-B and White Seedless. Cluster analysis of biochemical attributes divided the genotypes in three main classes on the base of similarity. Variations observed within class was 49.96% while the variation observed between classes was 50.04%. In genetic characterization, 12 SSR primers produced distinguishing results and showed a highly polymorphic result with maximum PIC values 0.654, 0.662 and 0.565 in primers VMC4A1, VVMD32 and VrZAG62, respectively. One synonym case was also identified in the study. BRI-001 and Sundar Khani showed 95.83% similarity between them and from 24 alleles, 23 of them were similar. In PCA plot, genotypes Sundar Khani and BRI-001 were too close to each other and were merged into each other which showed that these two genotypes were very similar in genetic characteristics. Similarly, in cluster analysis, both genotypes Sundar Khani and BRI-001 were in same class and had the least distance between them which showed similarity in them. Besides these two genotypes all genotypes present in Potohar showed diversity on a molecular basis which concluded that grape genotypes present in Pakistan have huge diversity and can be successfully used to improve existing genotypes.