The Jujube Tree ( Zizyphus JujubaLam)

Abstract

The jujube ( Zizyphus jujubaLam) is a small, deciduous, ornamental fruit tree native to Asia but grown in the southeastern United States for over 150 years. The genus Zizyphusis in the Rhamnacea, or buckthorn family, and includes about 40 species of plants in tropical and subtropical regions of the northern hemisphere (15). Seven Zizyphusspecies are native to the United States and Mexico, but none is of economic importance (11). Z. jujubaand Z. mauritianaLam. are the 2 most important species. Both are of old-world origin. The relationship between Z. jujubaand Z. mauritianais obscured in the literature by the frequent illegitimate use of the name Z. jujubaby writers referring to Z. mauritiana(11). Z. jujubais the less tropical of the 2, and is native where temperatures range from −6°C to 48°C and rainfall from 125 to over 2000 mm (5-80 inches (8). Z. jujubais deciduous and has glabrous leaves. Because it is more important in China than in any other country, it is commonly called the "Chinese date." By contrast, Z. mauritianais evergreen, has pubescent leaves, and is commercially most important in India, where it is called Ber or Indian jujube (15). The phylogenetic relationship between the 2 species has not been worked out, nor has their cross compatibility been investigated. Khoshoo and Singh (12) counted chromosomes for 35 cultivars of Indian jujubes. The basic or x number for the group was 12; 33 cultivars were tetraploid (2n = 48), 1 was pentaploid (2n = 60), and 2 were octaploid (2n = 96). Limited work on the Chinese jujubes (12) indicated that most may be diploids (2n = 24).