Assessment of Genetic Variability for Fruit Nutritional Composition in the Ex-Situ Collection of Jujube (Ziziphus spp.) Genotypes of Arid Regions of India

Abstract

Jujube or ber (Ziziphus spp.) is one of the most important fruit crops of India’s arid and semi-arid regions because of its high adaptability to resource constraints hot (semi)arid region. Jujube is a rich source of minerals, vitamins and dietary antioxidants to arid zone dwellers, where it is known as poor man’s apple. Given the present rising trends in discovering and exploiting plant-based health-promoting compounds, it is imperative to know the extent of variability with respect to fruit nutritional compositions present in the jujube germplasms. In this study, we assessed genetic variability for fruit nutritional and functional quality traits in eighteen jujube accessions belonging to three species (Z. mauritiana, Z. rotundifolia and Z. oenoplia) from an ex-situ collection from Indian arid and semi-arid regions in two consecutive fruiting seasons (2020-21 and 2021-22). Results revealed significant variability among eighteen jujube genotypes for important fruits physico-biochemical parameters. The IC 625864 (Z. oenoplia) identified as a superior accession for fruit antioxidant potential with having high levels of total phenols (256.2 mg/100 g dry weight) and total antioxidants (423 mg/100 g in FRAP). Moreover, IC 625849 (Z. mauritiana) and IC 625848 (Z. rotundifolia) were other genotypes containing high levels of phenols and total antioxidant (FRAP). Thus, while aiming for simultaneous improvement for total antioxidants with phenols, IC 625848, IC 625849 and IC 625864 genotypes can be considered as valuable resource for jujube fruit quality improvement program. Further, the high levels of phenotypic variance with high genotypic variance coupled with high heritability and genetic advance particularly for total antioxidants, total phenols, and ascorbic acid contents in fruits, indicating them to be considered as reliable biochemical markers to identify the productive genotypes having higher amounts of dietary antioxidants. Depending on the identified genotypes for their richness in the particular phytonutrients, these can be exploited either for table purpose or biofortification of other products, or using in jujube breeding program for quality improvement.