No abstract

Одной из самых вредоносных болезней подсолнечника является ложная мучнистая роса. К настоящему времени в мире обнаружено более 45 физиологических рас патогена. Эффективным методом контроля над возбудителем болезни является введение доминантных генов устойчивости к нему в растение-хозяина. Современные технологии генотипирования с помощью ДНК-маркеров позволяют контролировать наличие этих генов на каждом этапе селекции. Апробированы известные из литературных источников девять STS и три SSR-маркера генов Pl5, Pl6 и Pl8, контролирующих устойчивость к расам P. halstedii, для идентификации этих генов у линий-дифференциаторов устойчивости подсолнечника, входящих в международный тест-набор для идентификации рас P. halstedii. Был отобран и апробирован молекулярный STS-маркер НАР3, пригодный для идентификации локуса Pl6, контролирующего устойчивость подсолнечника к возбудителю ложной мучнистой росы.

During the last years in Rostov region of Russian Federation highly virulent biotypes of broomrape have propagated, affecting both hybrids of foreign breeding, and the native sunflower assortment, which used to be resistant earlier. Apart from that, the resistance of some known European sunflower types to broomrape races had disappeared, which testifies about the presence of the races F, G, H in the region at least. Consequently, the search of the sources of resistance is urgent.14 samples of annual and 27 of perennial wild sunflower from the collection of Kuban experimental station VIR were tested for resistance to the most virulent broomrape population. From the annual species only H. petiolaris had weak degree of affection (1-3 tubercles/plant), while the other were affected to a high degree. The majority of perennial sunflower samples have shown the immunity.Perennial wild species of the sunflower of the same name that were used earlier in the research of Ruso et al. (1996) as resistant species against the Spanish populations of broomrape, show resistance also to high virulent O. cumana, which had propagated in the Rostov region of the Russian Federation.The immunity to broomrape of the studied wild perennial sunflower samples is not related to the absence of stimulating effect of root exudations on the seeds of the parasite. The immunity is more likely connected to physiologicalbiochemical features of cortex root cells.

One of the most dangerous diseases on sunflower is downy mildew caused by oomycete Plasmopara halstedii. Introduction of dominant genes of resistance to this pathogen into a host-plant is the most effective economic and ecologically safe method of this pathogen control. The current DNA-technologies allow controlling these genes presence at the any stage of breeding. Currently, the genes Pl6, Pl13 and Plarg are the most effective ones controlling resistance to the most races of P. halstedii. We approbated known from the literary sources two STS and two SSR-markers of these genes on the lines and breeding samples. Three studied molecular markers – HаP3 (locus Pl6), ORS1008 (locus Pl13) and ORS509 (locus Plarg) – allowed us identifying the mentions genes in lines and breeding samples of VNIIMK. The studied DNA-markers can be interested in marker-associated sunflower breeding on resistance to a downy mildew pathogen.

After a long period (about 30 years) without broomrape problems in sunflower fields, intensive infestations were observed in some parts districts of Northern Caucasus. Virulence of the pathogen populations from some regions of Northern Caucasus was compared with those of race F from Spain and a mixture of races F, G, H from the European part of Turkey. It was shown that the broomrape populations from Northern Caucasus have heterogeneous structure. The populations Svetlogradskaya, collected in 2005, and Morozovskaya, collected in 2006, were most virulent. The first has the virulence comparable to one from Turkey and it is a mixture of nonvirulent and virulent races for the studied sunflower genotypes. Race F predominates in the mixture and has a there is an admixture (although insignificant) of more virulent individuals. The population Privolnenskaya from 2003 collection, is a mixture of different races also, but it is less virulent, containing race E and some insignificant admixture of more virulent individuals (most likely race F).