GENETIC DIVERSITY OF FRUITS IN WILD JUJUBE (Ziziphus lotus L. DESF.) NATURAL POPULATIONS FROM ALGERIA

Abstract

The analysis of genetic diversity between Ziziphus lotus populations using 35 ISSR primers showed a moderate polymorphism (61.31%), a polymorphism information content of 0.35, a resolving power of 2.51 and a marker index of 0.79. The evaluation of the discriminatory power of the ISSR markers was done by means of three parameters: (i) Polymorphic information content (PIC) which is the probability in detecting polymorphism by a primer or primer combination between two randomly drawn genotypes, it was calculated using the formula PIC = 1 - ?;2, where p¡ is the frequency of the ith allele (Sehgal et al. 2009; Lamare and Rao 2015); (ii) Resolving power (Rp) which is the ability of each primer to detect level of variation between individuals, it was calculated as Rp = EIb where Ib (band informativeness) takes the values of: 1 - [2|0.5 - p|], where p is the proportion of individuals containing the band (Prevost and Wilkinson 1999; Lamare and Rao 2015), and (iii) marker index (MI) in order to characterize the capacity of each primer to reveal or detect polymorphic loci among the genotypes, as a product of two functions - the polymorphic information content and effective multiplex ratio (EMR) (Milbourne et al. 1997; Varshney et al. 2007; Lamare and Rao 2015) : MI = PIC x EMR. A dendrogram was constructed based on the simple matching coefficient (SM) and the UPGMA (unweighted pair-group method with arithmetic averages) cluster method with the program NTSYSpc (Numerical Taxonomy and Multivariate Analysis System version 2.1). Molecular analysis The total number of bands produced by the IS SR primers (TBN), the number of polymorphic bands (PB), the percentages of polymorphic bands (% P), the polymorphic information content (PIC), the resolving power (RP) and the marker index of the ISSR primers are shown in Table 4. [...]at different altitudes strong isolation of populations may occur due to drastic differences in phenology between higher and lower altitude and mountain barriers which restrict the gene flow between populations causing complex and varied genetic variation (Lamare and Rao 2015).