Biodiversity and Conservation of Date Palm

Abstract

Date palm is one of the main horticultural crops of the ancient and recent world and an important source of food. Geographical distribution between 24° and 34°N latitude is considered as the main biodiversity centers of date palm distribution. There are about 5000 date palm cultivars besides countless varietal strains throughout the world, but every date-producing country has only few top commercial cultivars being cultivated and exported in all over the world. Commercial laboratories of tissue culture-derived date palm have contributed in spreading the cultivation and exchange safely cultivars of date palm worldwide. However, the date palm diversity is nowadays facing crucial problems such as Bayoud disease and red palm weevil (RPW) besides water shortage, urban settlement and disruption , rapid soil and genetic erosion and uncontrolled commercial exploitations of cultivating only elite cultivars. Numerous efforts have been made for in situ/on-farm conservation methods though effective but quite expensive and hence found only on small scale. The ex situ conservation methods of seed and DNA storage are not applicable due to their recalcitrant seeds and heterozygosity nature. Nevertheless, the in vitro conservation of date palm in form of shoot tips, axillary buds, embryos, and callus for longer periods by using slow growth or cold storage in vitro cultures and cryopreservation techniques is promising but might undergo somaclonal variation and less viability after thawing. The maintenance of field gene banks is found to be highly effective for conservation and providing the long-term preservation but relatively expensive and requiring huge space.