An analysis of genes for resistance against Indian stem rust races in two bread wheat cultivars     

R. N. Sawhney  V. L. Chopra  M. S. Swaminathan 《Euphytica》1979,28(3):651-660

Summary The genetic constitution of two bread wheat accessions from the International Spring Wheat Rust Nurseries (E 5883 and E 6032) has been studied for reaction to four Indian races of stem rust. Analysis of E 5883 has revealed that for each of the races 15C, 21 and 40 a single dominant gene operates for resistance. The dominant gene against race 15C was identified as Sr6. The dominant genes for resistance against races 21 and 40 were found to be different from the genes described so far. Resistance against race 122 is controlled by a single recessive gene producing characteristically a 2 type of reaction. This gene was identified as Sr8.The resistance of E 6032 against each of the races 15C, 21 and 40 is controlled by two genes, one dominant and one recessive, which act independently. Dominant genes effective against 15C, 21 and 40 were conclusively identified as Sr6, Sr5 and Sr9b, respectively. From the correlated behaviour against races 15C and 40 as well as from the phenotypes of the resistance reactions rhe same recessive gene, undescribed so far, operates against the two races. The second recessive gene operating against race 21 was also observed to be different from those so far designated. E 6032 was, however, found to be susceptible to races 122.The presence of Sr6 both in E 5883 and E 6032 against race 15C was further confirmed through F₂ and F₃ segregation data.  相似文献   

The importance of abortive stoma penetration in the partial resistance and nonhost reaction of adult barley and wheat plants to leaf rust fungi     

R. E. Niks 《Euphytica》1987,36(3):725-731

Summary Early stages of the infection process of Puccinia hordei isolate 1.2.1 and of a P. recondita f.sp. tritici isolate were studied on adult plants of four barley lines and one wheat line. Two of the barley lines are extremely susceptible to P. hordei, the other two have a very high level of partial resistance.A histological study based on a trypan blue staining indicated that stoma penetration by P. hordei isolate 1.2.1 was equally successful on the susceptible as on the partially resistant adult barley plants. Abortion of substomatal vesicles was rare in all lines. These results do not support a hypothesis that mechanisms of partial resistance in adult plants differ from those in seedlings by a substantial abortive stoma penetration.Also in the nonhost combinations wheat-P. hordei and barley-P. recondita f.sp. tritici inhibition of stoma penetration and of substomatal vesicle development appears to play a biologically insignificant role in adult plants.The proportion of stoma penetration on the leaf sheaths of two of the barley lines was as high as on the leaf blades of the flag leaf and the leaf below the flag leaf. There was no evidence for stomatal exclusion as a crucial factor in the relatively low infectibility of leaf sheaths to leaf-blade specialized rust species.  相似文献   

Genes for Resistance to Yellow Rust in Seedlings of Wheat Cultivars from Pakistan Tested with British Isolates of Puccinia striiformis   总被引：1，自引：0，他引：1  

M. S. Perwaiz  R. Johnson 《Plant Breeding》1986,97(4):289-296

Seedlings of 26 wheat caltivars from Pakistan were tested with 18 British races of P. striiformis. It is postulated that the race-specific genes Yr6, Yr7, Yr9 and perhaps Yr2 were present among the cultivars, and that there was other resistance not controlled by these genes.  相似文献   

Variation for resistance to Puccinia hordei in Ethiopian barley landraces     

Fekadu Alemayehu  J. E. Parlevliet 《Euphytica》1996,90(3):365-370

Summary Up to 100 single plant derived lines of 18 Ethiopian barley landraces were evaluated for infection type in the seedling and adult plant stage, and for latent period in the adult plant stage only. A low infection type indicates the presence of race-specific resistance genes of the hypersensitive type, while the latent period is the major component of the polygenic, partial resistance.In the seedling stage 1721 of these single plant derived landrace lines were assessed for infection type against two barley leaf rust races. In the adult plant stage 1227 from these 1721 lines were evaluated for infection type against one race. In the seedling stage 2 (against race 1-2-1) and 29 against race A) out of the 1721 lines showed an infection type lower than 6–7 on the 0 to 9 scale. In the adult plant stage none of the 1227 lines had an infection type lower than 6–7 against race 1-2-1.The variation between and within the landraces for latent period in the adult plant stage was large. Some landraces such as landrace 212845 showed a highly significant and longer mean latent period than most other landraces. Virtually all plants in all landraces carry at least some partial resistance.The near-absence of race-specific, major, resistance genes and the high frequency of moderate levels of partial resistance indicates that the durability of leaf rust resistance in Ethiopian barley landraces is due to the latter type of resistance, and that the multiline principle does not operate.  相似文献   

Genes conferring low seedling reaction to Mexican pathotypes of Puccinia recondita f. sp. tritici,and adult-plant responses of recent wheat cultivars from the former USSR     

R. P. Singh  A. Morgunov  J. Huerta-Espino 《Euphytica》1995,81(3):225-234

Fifty-five spring bread wheat (Triticum aestivum L.) cultivars, mostly released between 1975 and 1991 in eight leaf rust-prone spring wheat growing regions of the former USSR, were tested in the seedling growth stage for reaction to 15 Mexican pathotypes of Puccinia recondita f. sp. tritici. In total, seven known and at least two unknown genes were identified, either singly or in combinations: Lr3 (7 cultivars), Lr10 (14), Lr13 (5), Lr14a (1), Lr16 (1), Lr23 (3); the unknown genes were identified in 14 cultivars. The first unknown gene could be either Lr9, Lr19, or Lr25; however, the second unknown gene in 9 cultivars was different from any named gene. Twelve of the 15 pathotypes are virulent for this gene, hence its use in breeding for resistance will be limited. The cultivars were also evaluated at two field locations in Mexico with two pathotypes in separate experiments. The area under the disease progress curve and the final disease rating of the cultivars indicated genetic diversity for genes conferring adult plant resistance. based on the symptoms of the leaf tip necrosis in adult plants, resistance gene Lr34 could be present in at least 20 cultivars. More than half of the cultivars carry high to moderate levels of adult plant resistance and were distributed in each region.  相似文献   

The Aegilops ventricosa segment on chromosome 2AS of the wheat cultivar 'VPM1' carries the cereal cyst nematode resistance gene Cre5   总被引：2，自引：0，他引：2  

J. Jahier    P. Abelard    M. Tanguy    F. Dedryver    R. Rivoal    S. Khatkar  H. S. Bariana  R. Koebner 《Plant Breeding》2001,120(2):125-128

Previous studies showed that the intermediate level of resistance in bread wheat line ‘VPM1’ to pathotype Ha12 of the cereal cyst nematode could be conferred by an Aegilops ventricosa‐derived gene, CreX, in chromosome arm 2AS, which also carries the rust resistance genes Yrl7, Lr37 and Sr38. Near isogenic lines (NILs) differing for the presence and absence of the Ae. ventricosa‐derived linked genes Yrl7/Lr37/Sr38 were tested with cereal cyst nematode. Lines carrying Yr17 produced significantly fewer nematode cysts than the controls. An infested soil experiment produced better differentiation among resistant and susceptible genotypes. Susceptibility of ‘Trident’ indicated that linkage between CreX and Yr17 is incomplete. Microsatellite markers did not differentiate between ‘Trident’ and CreX‐carrying genotypes. However, Xgwm636 (104) was associated with the presence of Yr17 in all six genetic backgrounds. Since none of the reported cereal cyst nematode resistance genes is located in chromosome 2AS, CreX was designated as Cre5.  相似文献   

Inheritance of slow rusting to stem rust in wheat     

B. Skovmand  Roy D. Wilcoxson  B. L. Shearer  R. E. Stucker 《Euphytica》1978,27(1):95-107

Summary The inheritance of the slow rusting character was studied on F₅ progenies from seven spring wheat cultivars (Triticum aestivum) crossed in all possible combinations without reciprocals. The cultivars and their progenies were evaluated for slow rusting in 1974 and 1975 in epidemics of Puccinia graminis f. sp. tritici, races 15 and 151, and traces of other races. Slow rusting varied significantly among the parents and among the F₅ progeny of each cross. Transgressive segregation occurred in each cross, i.e. some progeny rusted more slowly than the parents and some faster. In crosses with both Idaed 59 and Kenya 58 the progeny distributions were skewed towards slow rust development but the distributions in the other crosses were normal. The genetic control of slow rusting was predominantly additive, and narrow sense heritability was approximately 80 percent. The number of segregating genes having an effect on slow rusting was estimated to be 2 to 12 pairs depending on the cross. Correlation between slow rusting and maturity was usually negative but in most crosses the relationship was small.Contribution No. 9624 from the Agricultural Experiment Station, University of Minnesota, St. Paul, Minnesota 55108.  相似文献   

A test of supposed mutants for stem rust resistance in wheat     

D. R. Knott 《Euphytica》1990,50(2):155-158

Summary Eight stem rust (Puccinia graminis tritici Eriks. and Henn.) resistant lines (designated TICENA lines) that had been selected by Veiga et al. (1981) following gamma radiation of BH-1146 wheat (Triticum aestivum L.) were studied. Six of the lines were resistant to race 15B-1 of stem rust and susceptible to race 56, and proved to carry the gene Sr7a. TICENA 4 carries two unidentified genes, each giving resistance to one of the two races. TICENA 10 carries Sr6, Sr7a and an unidentified gene giving resistance to race 56 but not 15B-1. The results raise doubts about the supposed origin of the lines as mutants.  相似文献   

Evaluation of seedling and adult plant resistance to stem rust in European wheat cultivars   总被引：2，自引：0，他引：2  

Amin K. Pathan  Robert F. Park 《Euphytica》2007,155(1-2):87-105

A total of 105 European wheat cultivars were assessed for seedling and adult plant resistance (APR) to stem rust using an array of Australian isolates of Puccinia graminis f. sp. tritici. Twenty-seven cultivars were susceptible at both seedling and adult plant growth stages. Twelve catalogued seedling stem rust resistance genes (Sr7b, Sr8a, Sr8b, Sr9b, Sr9g, Sr11, Sr15, Sr17, Sr29, Sr31, Sr36 and Sr38) were detected in the remaining cultivars, and 13 cultivars carried additional seedling resistance genes that could not be postulated with the isolates used. Low levels of APR to stem rust were found in the cultivars Artaban, Forno, Mec, Mercia, Pandas and Vlada. Although the genetic identity of this APR was not determined, it was clear that the only designated stem rust APR gene Sr2 was not present in any of the cultivars tested based on the absence of the linked traits seedling chlorosis and pseudo black chaff. One of these cultivars, Forno, is believed to carry the leaf rust APR gene Lr34, previously reported to be associated with improved resistance to stem rust. A detailed genetic characterisation of the APRs in these cultivars will be needed to understand their modes of inheritance and relationships with catalogued stem rust resistance genes. Such knowledge may help in developing cultivars with effective gene combinations that confer higher levels of protection.  相似文献   

Race-specificity of temperature-sensitive genes for resistance to Puccinia striiformis in Triticum dicoccoides   总被引：1，自引：0，他引：1  

Z. K. Gerechter-Amitai  C. H. van Silfhout 《Euphytica》1989,43(1-2):7-14

Summary Twenty-four entries of wild emmer possessing temperature-sensitive genes for resistance to yellow rust were studied in the seedling stage, at two temperature-profiles, with 15 pathogenic races from 11 countries in South America, Africa, Asia and Europe. It was shown that the majority of the resistance genes in these wild emmer entries were race-specific. In most of these entries a more resistant reaction was displayed at the higher temperature-profile; however in three entries a shift in reaction towards resistance was observed with certain races but towards susceptibility with some of the other races, suggesting that two different kinds of temperature-sensitive genes were involved in each of these entries. The similarity of temperature-sensitive genes occurring in wild emmer and in cultivated wheat is discussed.  相似文献