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Breeding for resistance to wheat diseases in Algeria


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By: A.Benbelkacem* and C.Djenadi
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Breeding for resistance to wheat diseases in Algeria

  1. 1. P.N.A.B Breeding for resistance to wheat diseases in Algeria A.Benbelkacem 1* and C.Djenadi² 1INRAA/URC Station ITGC, 25100 Algeria 2INRAA CRP M.Boualem Algiers Wheat for Food Security in Africa October 8 - 12, 2012, Addis Ababa, Ethiopia ABSTRACT Wheat production in Algeria is threatened by several biotic stresses. Diseases like Stripe rust (Puccinia striiformis) and leaf rust (Puccinia recondita), Septoria tritici leaf blotch, Tan spot (helminthosporium tritici repentis) and Fusrium or Take all are among the most prevalent diseases that occured this year mostly all over the Northern part of the country. Intensive cropping of high yielding varieties is rapidly replacing the traditional lower yielding landraces. At a breeding level in the National Wheat improvement Program, and since 2005, we had to go for a large screening of all cereal collections. As a result we could identify wheat lines that carry simultaneously adult plant resistance (APR) to leaf rust, yellow rust, Septoria leaf blotch and Tan spot in the favorable site and tan spot, septoria leaf blotch, stripe rust on bread wheat; take all is more present in durum wheat varieties in the semi arid site. Key words: Wheat, biotic stresses, screening, APR adult plant resistance, fleaf rust, stripe rust, septoria, tan spot, yield losses, breeding for disease resistance, Algeria . INTRODUCTION Results & discussion: Results of the surveys show that Durum wheat fields seem to be In Algeria, wheat is grown on approximately 2.5 million ha, though yields more affected this last season by take all or fusarium, they areare low due to abiotic and biotic constraints. Cereal production in Algeria (3 also slightly affected by leaf rust but not by yellow rust; in themillion tons on average) is facing several abiotic (drought, cold and salinity) bread wheat fields there is more susceptiblity to septoria tritici,and biotic (diseases and insects) constraints. During the best seasons and both leaf and yellow rusts. In general, all Northern area has awhere the abiotic stresses are hindered, diseases and insects are particular disease incidence.widespread and are the most damaging in all cereal growing areas of The severity is more apparent in the coastal and interior plainsAlgeria. Yield losses of 30 to 80% (epidemic situation) have been recorded than in the high plateau.almost annually. Septoria like diseases (50 to 65% incidence), leaf rust and, to Breeding efforts concentrate on achieving maximum yield potentials some extent, yellow rust were prevaling. Powdery mildew, root rotunder highly favorable environments, in addition to breeding for tolerance Fusarium or take all are becoming more present in wheat major biotic and abiotic stresses. In low rainfall areas, priority is given to Widespread stripe rust epidemics occurred in 2003 and 2004,drought tolerance and resistance to stresses such as cold and frost. and localized (eastern) in multiple years. Yield losses were asHowever, biotic stresses such as leaf rust (occurring in the sub-littoral high as 60 percent in susceptible varieties, but in recent years,regions), stripe rust, Septoria leaf blotch, and Tan spot are destructive in all major yield losses were prevented by widespread and timelywinter wheat regions and are considered the most important wheat applications of fungicides, based on accurate monitoring and thediseases in Algeria. Such diseases are therefore also a focus for breeders. prediction of disease epidemics. Annual surveys were undertaken to assess the prevalence, incidenceand severity of cereal diseases across the Northern part of the country in Studies of wheat cultivars have also identified sources of genetic resistance to stripeorder to draw maps that are very useful tool to tailor breeding objectives. rust. Durable resistance has been linked to genes such as Yr18, and some very effectiveThe survey allows also the collection of pathogen samples for major genes such as Yr9, Yr27, and Yr1 (which were associated with good parental linesdetermination of genetic diversity and virulence phenotyping. Durum and and hence extensively used in Algeria’s breeding program) have effectively reduced thebread wheat fields were evaluated for their reaction at the adult stage for impact of yellow rust for over a decade.the most prevailing diseases in different North East Algeria cereal growing Recent virulence on Yr27 has been detected in rust nurseries. The potential of wheat rustarea. On station work was mainly concentrating in screening for different epidemics from new emerging virulent rust races remains a real threat to most wheatpests and breeding for resistance. producing areas. New material selected during the yellow rust epidemic of 2004 has shown potential for resistance; four new cultivars (Tiddis, Boumerzoug, Akhamokh, and Massine) have been released in the past two last seasons and are being dispatched toMaterial & Methods: selected farmers for seed production. In collaboration with CIMMYT and ICARDA, theDiseases survey are one of the important ways to get acquainted of the program is also releasing a new wheat cultivar (Yacine) with high resistance to Ug99.pests situation in a region. North Eastern Algeria is mostly affected duringeach year by different pathogens. The survey is performed in the coastal,interior plains and high plateau areas. All wheat fields of the region areinspected in samples under natural conditions representing favorable andsemi arid regions; diseases are naturally expressed each year under fieldconditions. Severities and reaction types for the rusts and pycnidialcoverage for leaf blight diseases were recorded using the Saari & Prescottscale (1975).Nurseries developed through our breeding programs and newintroductions from CIMMYT & ICARDA were screened in hot spot sitesand selection was done at adult plant stage. ConclusionReferences: Biotic stresses are important in different wheat growing areas of Algeria; septoria likeBenbelkacem. A. (1991). Les céréales d’hiver. In Céréaliculture 25. ITGC.Caron. D. (1993). Maladies des blés et des orges. ITCF. Céréales de France. pp 43-53. diseases (septoria tritici, septoria nodorum and tan spot) and the main rusts (leaf and stripeEyal. Z, Scharen. A. L, Prescott. J. M et Van Ginkel. M. (1987). The Septoria diseases of wheat: rust) are the most prevailing ones. The existing wheat collections comprising, old land races,concepts and methods of disease management. CIMMYT, Mexico. pp 45. modern and new varieties have relatively low resistant rates (28% for bread wheat and 43% inSaari, EE & JM.Prescott, 1975. A scale for appraising the foliar intensity of wheat diseases.Plant Disease report. 59: 377-380. the durums). This studies gave a picture of the adult plant reaction to the different diseasesZillinsky F.J. (1983). Maladies commune des céréales à paille : Guide d’identification. CIMMYT, and permitted to select for the multiple resistant ones that can of use in the new wheatMexico. 141p. improvement program. Durable adult plant resistance sources are being increasingly used as parents in breeding programs. Creating and disseminating cultivars with continually improvedAcknowledgements: The authors acknowledge all the help given by CIMMYT and resistance needs to be a focus of African NARS, and the extension of modern technologicalICARDA . packages, such as integrated pest management (IPM), is needed.