Genetic Diversity and Relationships among Indian Jujube (Ziziphus mauritiana Lamk.) Cultivars Using Morphometric Characteristics, matK Barcoding, and ISSR Markers

Indian jujube displays genetic diversity and does not prominently display minute morphometric variations, and this makes correct identification a difficult and long-term task. However, little work has been conducted to bring jujube cultivars into domestication. So, the present study aimed to evaluate eleven cultivars of Indian jujube in terms of the fruit’s morphometric characteristics, as well as molecular marker studies by plastidial megakaryocyte-associated tyrosine kinase (matK) barcoding and inter-simple sequence repeats (ISSR) markers for species differentiation, identification, and relationships among Indian jujube cultivars. The results of the morphometric characteristics showed that the mean geometric diameter, surface area, sphericity, sphericity ratio, shape index, fruit length, fruit diameter, fruit weight, and seed weight varied among cultivars. The results also showed that the color values of L*, a*, and b* for fruits differed in different cultivars. In addition, the results showed a discrepancy in the genetic diversity parameters related to the matK barcoding, ISSR markers, and relationships among Indian jujube cultivars. Substantially, hierarchical clustering by heatmap revealed that ‘Zytoni’ and ‘Um-Sulaem’ with spines seem to be mono-clades distinct from other cultivars, which related to variations in the expression levels of genes. Therefore, they should be relied upon together to distinguish and identify cultivars in order to maximize the effectiveness of local germplasm conservation and exploitation.