In the present study, molecular fingerprinting among selected ten seeded type date palm trees growing at Al Dakhlah Oasis, New Valley Governorate in Egypt was carried out, in this approach 10 RAPD and 10 ISSR primers were used. In RAPD markers, primers 1, 3, 4, and 6 showed the highest level of polymorphism with number of polymorphic amplicons of 100%. While primers 7 and 8 resulted in the lowest number of polymorphic bands with polymorphism level of 62% and 63%, respectively. The similarity between Acsad-Dakhla 6 and 7 (0.76%) was observed as maximum similarity. While, Acsad-Dakhla 5 exhibited a minimum degree of similarity with all the seeded type date palm trees ranging from 33% to 49%. According to ISSR, highest polymorphism was generated by primers 8 and 9 (100%). While primers 4 and 2 produced the lowest polymorphism 50% and 55.6%, respectively. The highest similarity was observed between Acsad-Dakhla 8 and Acsad- Dakhla 9. Acsad-Dakhla 5 and Acsad-Dakhla 7 showed close relationship but Acsad-Dakhla 10 was at distant from all the seeded type date palm trees and did not lie in any subcluster. In combined analysis, the similarity between Acsad-Dakhla 6 and 7 were similar to Acsad-Dakhla 9 and 10 showed maximum similarity (85%). While, Acsad- Dakhla 2 and 5 exhibited a minimum degree of similarity with all the seeded type date palm trees (47%). A high genetic diversity among selected ten seeded type date palm trees was present.

A greenhouse pot experiment was carried out to investigate the effect of salinity and potassium at different levels alone or in various combinations on growth, mineral and proline content in leaves of plantlets of Phoenix dactylifera L. cv. Bartomouda (in vitro production, two years old from acclima tized them). The following treatments were applied: three levels of salinity Na Cl + Ca C12 w.w 2:1 (14000, 16000 and 18000 ppm.) and two levels of potassium (2000 and 3000 ppm) in addition to control (no salts or potassium used), salts and potas sium were added in the irrigation water. In general, all levels of salinity significantly decreased various growth parameters such as plant height, number of leaves and roots, root length, fresh and dry weights of leaves than that of the control. These parameters were decreased with increasing salinity levels, whereas it, significantly increased Na, Ca and K contents in leaves with high content of proline. The treatment 18000 ppm salts gave the highest significant reduction of the growth parameters, while caused an increase in proline Na, Ca, and K contents compared to control treatment (no salts) . This was true in both seasons. The applications of potassium significantly increased the previous growth parameters as compared with the control treatment (without salts and potassium) the treatment 3000 ppm had the highest results. Moreover the applications of potassium gave high alleviated the negative effects of salt stress, the treatment 3000 ppm gave the best results on the growth parameters of date palm plantlets grown under salinity condition . Regarding the interaction the obtained data revealed that the interaction between treatment 3000 ppm potassium and 14000 salts produced the highest significant results. Gen erally, from the obtained results it can conclude that the plantlets of date palm produced by tissue culture can be tolerated salt stress by addition of potassium which can significantly ameliorate the harmful effects of salts, positive effects on the growth parameters of the plantlets was showed by potassium applications.

The red palm weevil (RPW) Rhynchophorus ferrugineus (Coleoptera: Curculionidae) is the most destructive pest of date palm Phoenix dactylifera L. in Middle East particularly in ArabGulf countries. Distribution of RPW infestations in relation to some factors was studied in date palm farms in Qatif Governorate, EasternSaudi Arabia. For these studies, 80 farms containing over 11000 date-palm trees were inspected. A scale for grading the infestation severity was developed. Numerical, but not statistical differences were in infestation levels with RPW, were found among farms due to their location (desert or oasis), irrigation system (dripping or flooding), intercropping (with or without) and pruning condition (pruned or unpruned). However, too small farms (less than 100 palm trees/farm) or too large farms (over 1000 trees) were highly infested while farms of 400-800 trees/farm were the least infested. Over 42% of infestations were concentrated at or below the soil surface. Light or surface infestations formed 45% while severe or deep infestations formed 19% of total infestations. Trees of 5-10 years old were the most infested while trees over 15 years were the least infested.