This study aimed to determine the best combinations of plant growth regulators and other conditions in order to achieve organogenesis and multiplication directly from shoot tips of date palm (Phoenix dactylifera L.) var. Maktoom without callus formation so as to avoid any possibility of undesirable genetic variability. Results revealed that MS modified medium supplemented with 2.0 mg/L 2ip, 1.0 mg/L BA, 1.0 mg/L NAA and 1.0 mg/L NOA was the best for bud formation from shoot tip after 16 weeks (6.2 bud per explant). Subculturing the formed buds on liquid agitated multiplication medium supplemented with 4.0 mg/L 2ip, 2 mg/L BA, 1.0 mg/L NAA and 1.0 mg/L NOA gave the optimum average of buds number (12.6 buds). In elongation stage MS medium with 0.5 mg/L GA 3 and 0.1 mg/L NAA enhanced plantlet length to 5.3 cm. Optimum rooting percentage 90% was achieved when shoots were transferred to a medium with 1.0 mg/L NAA. The average root number after 8 weeks was 5.4 with 9.0 cm length. Rooted shoots (plantlets) were transplanted in small pots containing a mixture of peatmoss and perlite (2:1) and placed in plastic tunnels or in a greenhouse. The survival percentage was 85% after 3 months when the plants were transferred to bigger pots. These results define a successful protocol for the in vitro propagation of Maktoom cv. date palm. Proc. III rd IC on Date Palm Eds: A. Zaid et al. Acta Hort 736, ISHS 2007

Genetic diversity in 30 date palm (Phoenix dactylifera L.) cultivars in Iraq representing 24 female and six male cultivars was investigated using 22 microsatellite [simple sequence repeat (SSR)] primers. The tested SSR markers showed a high level of polymorphism. A total of 188 alleles were detected at the 22 loci ranging from three to 21 with an average of 8.54 alleles per locus. The average of heterozygosity for all cultivars was 0.503; genetic distance among cultivars varied from 0.171 to 0.938 indicating diverse relationships. The cultivar Ghanami Akhder was highly divergent from ‘Ghnami Ahmer’, whereas ‘Jamal Al-Dean’ was very closely related to ‘Qitaz’. Unweighted pair group method arithmetic average ordered date palm cultivars into two main clusters. Principal coordinate analysis exhibited the similar clusters of cultivars as in the dendrogram.

Iraq is the birthplace of the date palm, and historically it was the domestication center of this crop. Moreover, for some years, Iraq was the largest producer of dates in the world. Many factors negatively have affected both the production and natural genetic diversity of the crop. However, efforts are being made by the Iraqi authorities and researchers alike to compensate for the serious damage the date palm sector has experienced over the past 30 years. New approaches have been introduced including biotechnology, grove management, pest control, and industrial practices. Production limitations have been diagnosed and constraints are on their way to be resolved. Date palm plantations are under stress from many biotic and abiotic factors including key insect pests like dubas bug, lesser date moth, trunk and stalk borers, and Old World date mite. Date palm diseases cause serious damages to date palm trees especially where stress factors are present such as palm weakness, soil salinity, high water table, borers, and tree aging. The use of plant tissue culture to support propagation by offshoots is necessary and started in the early 1980s. Both direct organogenesis and callus induction with subsequent asexual embryo formation protocols were achieved. Approximately, 600 date palm cultivars were grown in Iraq before 1980; however, currently their number is reduced to 500. Morphological

Date palm (Phoenix dactylifera L.) is considered one of the great socioeconomic resources in the Middle East and the Arab regions. The tree has been and still is at the center of the comprehensive agricultural development. The number of known date palm cultivars, distributed worldwide, is approximately 3000. The success of genetic diversity conservation or any breeding program depends on an understanding of the amount and distribution of the genetic variation already in existence in the genetic pool. Development of suitable DNA molecular markers for this tree may allow researchers to estimate genetic diversity, which will ultimately lead to the genetic conservation of date palm. Simple sequence repeats (SSRs) are DNA strands, consisting of tandemly repeated mono-, di-, tri-, tetra-, or penta-nucleotide units that are arranged throughout the genomes of most eukaryotic species. Microsatellite markers, developed from genomic libraries, belong to either the transcribed region or the non-transcribed region of the genome, and there is rarely available information on their functions. Microsatellite sequences are especially suited to distinguish closely related genotypes due to a high degree of variability making them ideally suitable in population studies and the identification of closely related cultivars. This chapter focuses on the methods employed to characterize date palm genotypes using SSR markers.

Micropropagation has great potential for the multiplication of female and male date palms of commercially grown cultivars by using inflorescences. This approach is simple, convenient, and much faster than the conventional method of using shoot-tip explants. We describe here a stepwise micropropagation procedure using inflorescence explants of Iraqi date palm cultivar Maktoom. Cultured explants were derived from 0.5-cm-long spike segments excised from 8 to 10-cm-long spathes. About 70% formed adventitious buds on Murashige and Skoog (MS) medium supplemented with 2 mg/L naphthalene acetic acid (NAA), 4 mg/L benzylaminopurine (BAP), and 40 g/L sucrose and maintained in the dark for 16 weeks before transferring to normal light conditions. The best multiplication rate was achieved with 3 mg/L 2ip and 2 mg/L; for shoot elongation, the best medium is MS containing 0.5 mg/L BAP, 0.5 mg/L 2ip, and 1 mg/L GA. Well-developed shoots were cultured for rooting in half MS medium amended with 1 mg/L NAA and 45 g/L sucrose. Plantlets with well-developed roots were successfully hardened in the greenhouse. Inflorescence explants proved to be a promising alternative explant source for micropropagation of date palm cultivars.