Gene Analysis Of Wheat Leaf Rust Resistance Of Aegilops Tauschii And Wheat Cultivars (Lines)

Wheat leaf rust(Puccinia triticina) is one of the most important diseases in common wheat(Triticum aestivum L.) worldwide. Under favourable environmental conditions, the rust can cause yield losses of more than 40%. The most effective, economic and environmentally friendly way of controlling the disease is to use Lr genes in a breeding program. This type of interaction imposes a strong selection pressure on the pathogens to overcome the major gene resistance. Limited information is available on the possible Lr genes that are present in current wheat lines. Understanding the Lr genes in released wheat cultivars would be very useful for breeding new cultivars with resistance to leaf rust. In this paper, some accessions of Aegilops tauschii and wheat cultivars(lines) were evaluated the wheat leaf rust resistance in the seedling and adult stages using the genes postulation and molecular marker-assisted selection. The objectives are to evaluate wheat leaf rust resistance, comfirm the distribution of Lr genes in the materials, looking for the excellent wheat leaf rust resistence materials.1. The resistance of seventeen A. tauschii lines from Canadian to wheat leaf rust was evaluated and deduced at seedling stage by detached leaves and at adult stage in the field. The results show that A. tauschii accessions 30805, 30941, 30942, and 30938 show immune to P. triticina strains at both seeding and adult stage. The results indicated that these four accessions contained effective leaf rust resistance gene with high resistance to wheat leaf rust. It was deduced to have broad research value in breeding programs and wheat leaf rust control. The resistance genes in the accessions of A. tauschii were postulated, the result showed that 30939 and 30802 may contain Lr B, 30813, 30811 and 30803 may contain Lr18, 30941 and 30942 may contain Lr21, 30938 may contain Lr B and Lr15, 30823 and 30940 may contain Lr32, 30819 may contain Lr33. The results of marker assisted detection showed that Lr1 might be present in 40033 and 30823, and Lr9 was identified in 42471, and Lr21 was found in 30942. Five genes including Lr19, Lr24, Lr28, Lr29 and Lr34 cannot be detected in the 17 accessions.2. The specific STS marker of Lr10, Lr20, Lr26, Lr28, Lr34 and Lr47 were used in this study to do molecular marker-assisted detection in 53 wheat cultivars. 17 materials contained Lr10, Lr26, Lr28 and Lr34. Lr10 was identified in Fengkang13, 6068, Selkrik, and AC DOMAIN. Lr26 was found in Daliwang, Lufu16, Taikong8, Taiyu28, Wenmai8, Jimai30, Beijing837, and Niuzhute. Lr28 was found in Jinan17 and Funo. Lr34 was found in Mingxian169, 6068, Long94-4083, and Columbus. Lr20 and Lr47 were not present in the 53 materials according to the STS markers.3. To evaluate the wheat leaf rust resistance of two wheat production cultivars and eight wheat accessions of USA, 10 tested lines and 35 near isogentic lines with known leaf rust resistance genes(Lr genes) were inoculated with 12 Chinese P. triticina pathotypes at the seedling and adult stages respectively. Two wheat materials including 09p205 and 09p200, showed high resistance to all the used pathotypes at the both seedling and adult stages respectively. Three materials, Xinmai 16, 00-225-2-1-2-2, and 21941-6 showed adult-plant resistance. Four materials, 21898-3, 21924-4, 21915-3, and 21982-1 showed slow rusting resistance. In addition, 24 molecular markers were used to assess the presence of 20 known Lr genes in the 10 materials. The 10 wheat materials contain Lr2 c, Lr3 ka, Lr9, Lr14 a, Lr26, Lr34, and Lr37 either alone or in combination. Eight materials containing no less two Lr genes, 5 materials contain adult plant Lr gene. Beside Shimai 16, the others had application potential in wheat production.