000			04218nab a22003977a 4500
001			G89613
003			MX-TxCIM
005			20220607163754.0
008			220607s2006 kz |||p|op||| 00| 0 rus d
022			_a1814-8417
040			_aMX-TxCIM
041			_arus
090			_aCIS-4879
100	1		_aMaraite, H. _922659
245	1	0	_aRelevance of pathogen diversity in management of leaf spot and leaf blight diseases on wheat in central Asia
260			_aKazakhstan : _bMinistry of Agriculture of the Republic of Kazakhstan, _c2006.
340			_aComputer File|Printed
500			_aAbstract in English and Russian.
500			_aPeer-review: No - Open Access: No
500			_aPeer review
520			_aDuring Helminthosporium leaf blight surveys performed in 2003, 2004 and 2005 between May and August on winter and spring wheat in various regions of Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan and in Western Siberia (Russia), samples of wheat leaves showing leaf spot and leaf blight symptoms were collected at 113 locations or plots and analysed at the Université catholique de Louvain, Belgium. The analysis under a microscope and/or isolation revealed the presence of Pyrenophora tritici-repentis on 77% of the samples. Its prevalence fell to 31% on the samples from the Omsk region in Western Siberia where Phaeosphaeria nodorum was detected on all analysed samples. Overall, P. nodorum was associated with lesions on 50% of the samples, with a strong decline in prevalence in South Kazakhstan, Kyrgyzstan and Uzbekistan. Mycosphaerella graminicola was detected on 23% of the samples and appeared more frequent than P. nodorum in the latter regions. Mixed infections of two or even three of these pathogens were observed on 43% of the samples. Cochliobolus sativus was detected on only 10% of the samples. Some 101 single conidia strains of P. tritici-repentis were inoculated for race characterization on a set of differential wheat genotypes. Of these, 87% belonged to race 1, while only 7%, 5% and 1% were identified as race 2, race 3 and race 4, respectively. Evolution in race prevalence in Central Asia might affect the stability of tan spot resistance. The distribution of the mating type ideomorphs was determined for 49 P. nodorum isolates. The proportion of MAT-1 and MAT-2 isolates appeared balanced (23:19) among the Kazakh and Russian origins, but no MAT-2 isolate has yet been found in Tajikistan. The role of ascospores in glume blotch epidemiology might be reduced for a population with a skewed proportion of the mating types. MAT-1 and MAT-2 ideomorphs of M. graminicola were present in a rather balanced proportion (24:17) throughout the surveyed area. Sensitivity in vitro of the P. nodorum and M. graminicola isolates to propiconazole (Tilt) and azoxystrobin (Amistar) was assessed in PDB. No resistant isolate was detected. The EC50 values of propiconazole and azoxystrobin ranged for M. graminicola from <0.003 to 0.013mg/L and 0.01 to 0.078mg/L, respectively; and for P. nodorum from 0.013 to 0.085mg/L and 0.016 to 0.267mg/L, respectively. The abundance of crop residues associated with conservation tillage practices, together with the frequent observation of Pyrenophora tritici-repentis pseudothecia on the stubbles as well as the regular isolation of both mating types of Phaeosphaeria nodorum and M. graminicola from the leaves, highlight the risk of a rapid evolution in the population structure of these pathogens with regard to the dispersion of virulence or fungicide resistance genes.
536			_aResearch and Partnership Program
546			_aText in Russian
594			_aINT1237
650		7	_2AGROVOC _91197 _aPathogens
650		7	_2AGROVOC _91206 _aPlant diseases
650		7	_2AGROVOC _91310 _aWheat
650		7	_2AGROVOC _911012 _aDisease management
651		7	_2AGROVOC _94372 _aCentral Asia
700	1		_aMercado Vergnes, D. _922893
700	1		_aRenard, M.E. _922895
700	1		_aZhanarbekova, A. _922894
700	1		_9826 _aDuveiller, E. _gDG's Office _8INT1237
773	0		_tAgromeridian _n634522 _gv. 2, no. 3, p. 105-114 _dKazakhstan : Ministry of Agriculture of the Republic of Kazakhstan, 2006. _wG89379 _x1814-8417
942			_cJA _2ddc _n0
999			_c26524 _d26524