Sedra M.H.,Center Regional Of La Recherche Agronomique Of Marrakech |
Zhar N.,Center Regional Of La Recherche Agronomique Of Marrakech
Acta Horticulturae | Year: 2010
The date palm (Phoenix dactylifera L.) is the biggest crop in Moroccan oasian ecosystem that produces dates and other products and preserves this system which is threatened by desertification. Several other constraints have also perturbed the development of the date palm sector, among them the Bayoud disease, caused by Fusarium oxysporum f.sp. albedinis (Foa) constitutes a serious threat for these oases. In order to control this disease, the use of resistant varieties was until now the most common way. However, the resistance durability depends on pathogen genetic variability notably the appearance of new physiological races. The last studies showed that the variability level was very low. Our research work aims to study the genetic variability in Fusarium oxysporum populations of 45 pathogenic and non pathogenic strains from different areas in Morocco and other Arab countries using specific and non specific PCR techniques. The pathogen strains of F. o. f. sp. canariensis (Foc) isolated from Canary island palm (Phoenix canariensis L.) have been used in this study. New RAPD and microsatellites ISSR primers were selected; these primers have generated 185 polymorphic markers. The dendrogram using average linkage and established by polymorphic bands revealed by RAPD and ISSR analyses showed the polymorphism in Foa strains without discriminating them to other strains and globally clustered the strains based on their geographic or isolation origins. The specific PCR using two specific couples of primers showed a relatively weak reliability level to detect Foa strains.
Abahmane L.,Center Regional Of La Recherche Agronomique Of Marrakech
Acta Horticulturae | Year: 2010
Research activities on date palm micropropagation have permitted to multiply a great number of known cultivars worldwide. However, micropropagation of some important rare or selected date palm genotypes is still hampered by the lack of offshoots. To overcome this problem, the use of tissues excised from inflorescences, at their emergence, has permitted to succeed in micro-propagation of many selected genotypes by using the organogenesis technique. However, some selected genotypes are still recalcitrant and it is very difficult to regenerate vegetative buds directly from cultured explants. In order to adapt this technique to such recalcitrant genotypes, the embryogenesis technique was tested to succeed in their multiplication. Three different auxins (2,4-D, Picloram and Dicamba) were tested on callus initiation from inflorescence tissues of a selected date palm genotype INRA-D12. Embryogenic callus was obtained on medium containing 12 mg L -1 of Dicamba, 2 mg L -1 of BA and 300 mg L -1 of activated charcoal. Obtained callus was multiplied on culture media devoid of 2,4-D and activated charcoal. After 4 multiplication cycles, a mixture of somatic embryos and vegetative buds were regenerated. Obtained buds were successfully multiplied and complete plantlets were regenerated. Vegetative buds were similar, both in terms of multiplication rate and behaviour, to those obtained directly from explants excised from date palm shoot tips. Produced plantlets were successfully acclimatized in a greenhouse and are now ready to be transferred to soil for field evaluation. Some vitro-plants will also be reserved for Bayoud resistance tests. In the present protocol, a relatively low auxin concentration and a limited number of callus multiplication cycles were used and this will be more secure concerning true-to-typeness of regenerants.
Ait Hmida A.,Center Regional Of La Recherche Agronomique Of Marrakech
New Medit | Year: 2010
The profitability of superintensive olive production has been at the heart of the debate over the past three years. Farmers and professionals are discussing whether this system is more cost-effective than intensive olive cropping. The aim of the present study is to address this issue through the financial assessment of two projects on olive cropping methods, intensive with 277 trees/Ha for cv. Moroccan Picholine and super-intensive with 1333 trees/Ha for cv. Arbequina, respectively. This work was conducted in the Haouz plain near Marrakesh. The results indicate that both projects are profitable with a 20.63% IRR for the superintensive and a 17.84% IRR for the intensive. The payback period on the investment is, respectively, of 8 years against 15 years for the two production methods. This delay in the payback period for the intensivelygrown olive trees is due to the fact that the cv. Morroccan Picholine comes into production later.