黄淮麦区26个小麦品种抗叶锈病初步鉴定

根据生物问遗传学原理，分析了26个黄淮麦区小麦品种对15个叶锈菌系的抗性状况，抗性最好的品种是徐州174，毒力频率为33．3％，毒力频率低于60％的仅有百农64、徐州8697等7个品种，2号和3号叶锈菌系的抗源品种最多，有22个，而14号和15号叶锈菌系无一抗源品种。总之，供试品种的抗叶锈性较差。     

A combination of leaf rust resistance gene Lr34 and lesion mimic gene lm significantly enhances adult plant resistance to Puccinia triticina in wheat

Leaf rust caused by Puccinia triticina is an economically-important disease in wheat worldwide.A combination of different types of resistance genes may significantly enhance rust resistance under rust-favorable conditions.To investigate the interactions between the rust resistance gene Lr34 and the lesion mimic gene lm on 1BL in Ning 7840,a segregating F8-10 population of 180 recombinant inbred lines was developed from Ning 7840/Chokwang and evaluated for both lesion mimic expression and leaf rust response at the adult plant stage in a greenhouse.A major quantitative trait locus(QTL),derived from Sumai 3,was co-localized with Lr34 on chromosome 7D and explained 41.5% of phenotypic variations for rust severity and 22.1% for leaf tip necrosis(LTN).The presence of Lr34 was confirmed by Lr34-specific markers cssfr1 and cssfr2 in Ning 7840 and Sumai 3.Unlike Lr34,lm conditioned a spontaneous lesion mimic phenotype and had a significant effect on reducing uredinial size,and a smaller effect on severity.Additive effects were observed between lm and Lr34 for severity and LTN,and an epistatic effect was observed for infection type.Single marker analysis also identified several other QTL with minor effects on severity,infection type,or LTN.     

2002年大竹县小麦条锈病流行原因及综合治理

经分析2002年大竹县小麦条锈病突发流行的原因,主要是条中30、31和32上升为优势种群,导致绵阳系列的小麦品种持久抗病性丧失,以及2002年春季的持续低温天气和防治不力等因素.提出了大竹县今后小麦条锈病综合治理的措施.     

Genes for resistance to stripe rust on chromosome 2B and their application in wheat breeding

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most damaging diseases of wheat worldwide. Growing resistant cultivars is the most economic and environmental friendly way to control the disease. There are many resistance genes to stripe rust located on wheat chromosome 2B. Here, we propose a strategy to construct the recombinant wheat chromosome 2B with multiple resistances to stripe rust by making crosses between wheat lines or cultivars carrying Yr genes and using marker-assisted selection, based on the reported information about resistance spectrum, chromosomal location, and linked markers of the genes. Pyramiding the resistance genes on 2B would afford a valuable strategy to control the disease by cultivating varieties with durable resistance. The possibility, efficiency, and prospect of the suggested strategy are reviewed in the paper.     

Identification of an AFLP marker linked to the stripe rust resistance geneYr10 in wheat

AFLP analysis of near-isogenic lines of the stripe rust resistance gene Yr10 was carried out with 6 PstⅠ- primers and 10 TaqⅠ-primers with the donor parent of Yr10 gene as the check. A total of about 4200 distinguishable bands were amplified, of which 5 were stable. The genetic linkage of the 5 polymorphic DNA fragments with the target gene were tested preliminarily on a segregating F₂ population derived from a cross between the gene donor parent “Moro” and susceptible cultivar “Mingxian 169”. The DNA fragment PT0502 was found closely linked to the Yr10 gene and cloned and sequenced. Based on the sequence specific primers for PCR were designed and synthesized. Genetic linkage analysis with 195 segregating F₂ plants indicated that the genetic distance was 0.5 cM between the main product SC₂₀₀ fragment produced by PCR with the primers and the Yr10 gene. The primers can be used to detect the Yr10 gene quickly, effectively and exactly.     

AFLP fingerprinting of Chinese epidemic strains of Puccinia striiformis f. sp. tritici

Amplified fragment length polymorphism (AFLP) was used to fingerprint the epidemic strains CY25, CY27, CY28, CY29, CY30, CY31, Hy3, Hy7, Sy13 and a mutant strain WV-4 of P. striiformis f. sp. tritici, the pathogen of wheat stripe rust. The results showed that (i) genetic diversity existed in the pathogen populations, and based on it a dendrogram of these strains was constructed by unweighted pair-group mean average to demonstrate the relationships of the tested strains; (ii) no significant correlation between virulence of the pathogens and the polymorphism of DNA fingerprints was found; ( iii ) AFLP fingerprints showed higher polymorphism than that of the virulence variation; (iv) several new pathotypes identified might evolve independently of the reference strains identified before.