Jojoba is considered a promising oil crop and is cultivated for diverse purposes in many countries. The jojoba seed produces unique high-quality oil with a wide range of applications such as medical and industrial-related products. The plant also has potential value in combatting desertification and land degradation in dry and semi-dry areas. Although the plant is known for its high-temperature and high-salinity tolerance growth ability, issues such as its male-biased ratio, relatively late flowering and seed production time hamper the cultivation of this plant. The development of efficient biotechnological platforms for better cultivation and an improved production cycle is a necessity for farmers cultivating the plant. In the last 20 years, many efforts have been made for in vitro cultivation of jojoba by applying different molecular biology techniques. However, there is a lot of work to be done in order to reach satisfactory results that help to overcome cultivation problems. This review presents a historical overview, the medical and industrial importance of the jojoba plant, agronomy aspects and nutrient requirements for the plant’s cultivation, and the role of recent biotechnology and molecular biology findings in jojoba research.

Genetic diversity among 13 different cultivars of date palm (Phoenix dactylifera L.) of Saudi Arabia was studied using random amplified polymorphic DNA (RAPD) markers. The screening of 140 RAPD primers allowed selection of 37 primers which revealed polymorphism, and the results were reproducible. All 13 genotypes were distinguishable by their unique banding patterns produced by 37 selected primers. Cluster analysis by the unweighted paired group method of arithmetic mean (UPGMA) showed two main clusters. Cluster A consisted of five cultivars (Shehel, Om-Kobar, Ajwa, Om-Hammam and Bareem) with 0.59-0.89 Nei and Li's coefficient in the similarity matrix. Cluster B consisted of seven cultivars (Rabeeha, Shishi, Nabtet Saif, Sugai, Sukkary Asfar, Sukkary Hamra and Nabtet Sultan) with a 0.66-0.85 Nei and Li's similarity range. Om-Hammam and Bareem were the two most closely related cultivars among the 13 cultivars with the highest value in the similarity matrix for Nei and Li's coefficient (0.89). Ajwa was closely related with Om-Hammam and Bareem with the second highest value in the similarity matrix (0.86). Sukkary Hamra and Nabtet Sultan were also closely related, with the third highest value in the similarity matrix (0.85). The cultivar Barny did not belong to any of the cluster groups. It was 34% genetically similar to the rest of the 12 cultivars. The average similarity among the 13 cultivars was more than 50%. As expected, most of the cultivars have a narrow genetic base. The results of the analysis can be used for the selection of possible parents to generate a mapping population. The variation detected among the closely related genotypes indicates the efficiency of RAPD markers over the morphological and isozyme markers for the identification and construction of genetic linkage maps.

Varietal identification of olives is an intrinsic and empirical exercise owing to the large number of synonyms and homonyms, intensive exchange of genotypes, presence of varietal clones and lack of proper certification in nurseries. A comparative study of morphological characters of eight olive cultivars grown in Saudi Arabia was carried out and analyzed using NTSYSpc (Numerical Taxonomy System for personal computer) system segregated smaller fruits in one clade and the rest in two clades. Koroneiki, a Greek cultivar with a small sized fruit shared arm with Spanish variety Arbosana. Morphologic analysis using NTSYSpc revealed that biometrics of leaves, fruits and seeds are reliable morphologic characters to distinguish between varieties, except for a few morphologically very similar olive cultivars. The proximate analysis showed significant variations in the protein, fiber, crude fat, ash and moisture content of different cultivars. The study also showed that neither the size of fruit nor the fruit pulp thickness is a limiting factor determining crude fat content of olives.

This investigation reports the impact of water stress on some anatomical traits of sapwood and other functional morphological features of green assimilatory shoots of Calligonum comosum L'Hér. (Erta), a good source of fuel wood. The major findings of the study are that in this species drought makes for: a) narrower vessels both in earlywood and latewood, b) thicker vessel walls, c) longer vessel elements and fibers, d) a higher frequency of small latewood vessels and a lower frequency of large earlywood vessels, e) narrower growth rings, f) a lower total fraction of vessels per xylem area, g) higher wood density, h) narrower depth of conducting phloem, i) higher specific mass of green photosynthetic shoots, and j) a lower chlorophyll content. Extremely narrow vessels arranged in radial files in latewood were recognized having 40% increased volume fraction in nonirrigated plants. This adaptation is believed to play an important role in the species survival during hot summer months.

To cite this paper: S. Hadi, N.S. Abstract'Shees' fruit abnormality manifested as cluster of small fruit-like structures on a single peduncle occurs at a high frequency in tissue culture derived plants of date palm. The abnormality is akin to parthenocarpy, which is known to be caused by altered hormone profile of flowers/fruits in many species. This study was conducted to elucidate the hormonal profile of date palm flowers and early fruits and to identify the hormones associated with 'shees' fruit formation. Hormone levels in young flowers/fruits of normal and 'shees'-bearing plants of cultivars 'Barhy' and 'Nabtet-Saif' were studied with HPLC at the time of pollination and subsequently after 10 and 20 days. In all these samples, out of seven hormones detected by HPLC, levels of indole-3-acetic acid (IAA) and gebberellic acid (GA 3 ) were significantly higher, while that of a 'kinetin-like' compound and an unknown compound were significantly lower in 'shees' flowers/fruits as compared to the normal counterparts. Other three unknown compounds did not show significant variations between normal and 'shees' fruits. Kinetin-like compound showed the same elution properties as kinetin standard during HPLC procedures. The compound was purified and an attempt was made to characterize the molecule with gas chromatography-mass spectrometry (GC-MS). On the basis of Wiley-229 library hit (entry 101383) the compound was identified as Benzeldehyde, 2-hydroxy-[(2-hydroxyphenyl) methylene] hydrazone with formula: C 14 H 12 N 2 O 2 and Mol weight: 240. We have tentatively designated the compound as BHH and are reporting the occurrence of this compound for the first time in date palm.