Introgression of Stem Rust Resistance into Popular Kenyan Wheat Varieties to Improve Production

2018 ◽  
Vol 17 (1) ◽  
pp. 1-11
Author(s):  
Tubei Jackline ◽  
Fredrick Njoka ◽  
Omwoyo Ombori ◽  
Peter Njau
1971 ◽  
Vol 13 (2) ◽  
pp. 186-188 ◽  
Author(s):  
D. R. Knott

Tests were carried out to identify and locate the genes for resistance to races 15B-1L and 56 in Hope and H-44. The gene Sr1 which conditions resistance to race 56 was found to be either very closely linked or more probably allelic to Sr9. It is proposed that it be redesignated Sr9d. The gene Sr2 which conditions adult plant resistance to race 56 appears to be on chromosome 3B. The recessive gene conditioning resistance to race 15B-1L was identified as sr17 which is on chromosome 7B.


2019 ◽  
Vol 20 (19) ◽  
pp. 4887 ◽  
Author(s):  
Li ◽  
Dong ◽  
Ma ◽  
Tian ◽  
Qi ◽  
...  

Wheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt) had been a devastating foliar disease worldwide during the 20th century. With the emergence of Ug99 races, which are virulent to most stem rust resistance genes deployed in wheat varieties and advanced lines, stem rust has once again become a disease threatening global wheat production. Sr52, derived from Dasypyrum villosum and mapped to the long arm of 6V#3, is one of the few effective genes against Ug99 races. In this study, the wheat–D. villosum Robertsonian translocation T6AS·6V#3L, the only stock carrying Sr52 released to experimental and breeding programs so far, was crossed with a CS ph1b mutant to induce recombinants with shortened 6V#3L chromosome segments locating Sr52. Six independent homozygous recombinants with different segment sizes and breakpoints were developed and characterized using in situ hybridization and molecular markers analyses. Stem rust resistance evaluation showed that only three terminal recombinants (1381, 1380, and 1392) containing 8%, 22%, and 30% of the distal segment of 6V#3L, respectively, were resistant to stem rust. Thus, the gene Sr52 was mapped into 6V#3L bin FL 0.92–1.00. In addition, three molecular markers in the Sr52-located interval of 6V#3L were confirmed to be diagnostic markers for selection of Sr52 introgressed into common wheat. The newly developed small segment translocation lines with Sr52 and the identified molecular markers closely linked to Sr52 will be valuable for wheat disease breeding.


1941 ◽  
Vol 19c (11) ◽  
pp. 438-445 ◽  
Author(s):  
T. Johnson ◽  
Margaret Newton

Eighteen stem rust resistant wheat varieties were tested, in the greenhouse, for their reaction to three physiologic races of Puccinia graminis Tritici Erikss. and Henn. at three different temperatures: a constant low temperature of about 60° F., a constant high temperature of about 80° F., and an intermediate temperature which fluctuated daily from 50° to 55° F. at night to 70° to 85° F. at midday.At the low and at the intermediate temperature some of the varieties proved immune while others proved highly or moderately resistant. At the high temperature five varieties (Bokveld, Iumillo, Gaza, Red Egyptian, and N.A. 95 Egypt) were immune or highly resistant; six varieties (Marquillo × Waratah, Hope, Hochzucht, Minor, Bobin Gaza Robin, and Federation × Acme) were moderately resistant; and seven varieties (Kenya, Syria, McMurachy, Sweden, Rhodesian, Talberg, and Eureka) were moderately or completely susceptible.


1970 ◽  
Vol 48 (8) ◽  
pp. 1439-1443 ◽  
Author(s):  
P. Bartoš ◽  
G. J. Green ◽  
P. L. Dyck

Thirty-four European wheat cultivars were classified into eight groups according to their reactions to seven North American races of Puccinia graminis f. sp. tritici. Cultivars of seven groups were crossed with a variety or single gene line having similar rust reactions. These crosses indicated that the resistance of Hybrid 80-3, Stabil, and Vrakuňská (group 1) was conferred by stem rust resistance gene Sr5; Admonter Früh (group 2) carries Sr5 and an unidentified gene; Flevina (group 4) carries Sr11; Erythrospermum 974 (group 5) carries Sr5 and Sr8; Étoile de Choisy (group 6) carries an unidentified gene for moderate resistance to all the races used; and Mironovskaja 808 (group 7) and Belocerkovskaja 198 (group 8) each carry an unidentified gene. The five cultivars in group 3 were not studied genetically but they react like Marquis and may carry Sr7b.


2016 ◽  
Vol 52 (No. 4) ◽  
pp. 242-249 ◽  
Author(s):  
Li Tian-ya ◽  
Wu Xian-xin ◽  
Xu Xiao-feng ◽  
Wang Wan-lin ◽  
Cao Yuan-yin

To determine stem rust resistance genes of wheat varieties in Yunnan province, 11 Chinese strains of Puccinia graminis f.sp. tritici with different virulence and 1 artificial mutant strain were used in 110 wheat varieties. The results indicated that among the 45 Sr genes, Sr31, Sr5, SrTmp, Sr30, Sr36, Sr8a, Sr11, Sr24, Sr29, Sr34, Sr9e, Sr26, Sr38, Sr47, and SrTt3 were characterised in 55 wheat varieties singly or in combination. Sr5, Sr31, SrTmp, Sr36, and Sr30 were contained in 17, 16, 5, 5, and 3 cultivars, respectively. Six cultivars contained Sr24 and/or Sr34. Three plant materials likely contained one or more of Sr8a, Sr11, Sr34, and Sr23 genes as well as other unknown genes. The 16 immune or highly resistant varieties contained one or more of Sr9e, Sr26, Sr38, Sr47, SrTt3, and other unknown resistance genes. The reaction types on 22 of the tested cultivars were different from those on Sr genes tested, and their resistance genes could not be analysed. Additionally, 17 varieties were susceptible to all the tested strains, having no postulation value. Our study provides a basis for improved breeding of stem rust resistant wheat in China.


2011 ◽  
Vol 47 (Special Issue) ◽  
pp. S146-S154 ◽  
Author(s):  
A. Kokhmetova ◽  
A. Morgounov ◽  
S. Rsaliev ◽  
A. Rsaliev ◽  
G. Yessenbekova ◽  
...  

In Central Asia, stem rust (Puccinia graminis f.sp. tritici) causes considerable damage, especially during growing seasons with high rainfall. Ug99 is a race of stem rust that is virulent to the majority of wheat varieties. To develop disease-free germplasm, wheat material was screened using the predominant stem rust races of Kazakhstan and tested in two nurseries; CIMMYT-Turkey and the Plant Breeding Station at Njoro, Kenya. A total of 11 pathotypes of P. graminis f.sp. tritici were identified in Kazakhstan from the stem rust samples collected in 2008–2009. In particular, pathotypes TDT/H, TPS/H, TTH/K, TKH/R, TKT/C and TFK/R were highly virulent. Of the 170 advanced lines of wheat, 21 CIMMYT lines resistant to 5 aggressive Kazakhstani pathotypes of P. graminis were identified. A high level of resistance was observed in 11 wheat cultivars and advanced lines: Taza, E-19, E-99, E-102, E-572, E-796, E-809 (Kazakhstan), Ekinchi (Azerbaijan), Dostlik, Ulugbek 600 (Uzbekistan) and Umanka (Russia). Based on data obtained from Turkey-CIMMYT and the Plant Breeding Station Njoro, Kenya nurseries, out of 13 tested entries, 6 wheat breeding lines which were resistant to both stem and yellow rust and 10 wheat lines which showed high and moderate levels of resistance to Ug99 were selected. Using the sequence tagged site (STS) molecular marker Sr24#12, associated with Sr24/Lr24, seven wheat entries resistant to stem rust were identified. These results will assist breeders in choosing parents for crossing in programmes aimed at developing varieties with desirable levels of stem rust resistance in Kazakhstan and they will also facilitate stacking the resistance genes into advanced breeding lines.


2016 ◽  
Vol 106 (11) ◽  
pp. 1352-1358 ◽  
Author(s):  
Jayaveeramuthu Nirmala ◽  
Shiaoman Chao ◽  
Pablo Olivera ◽  
Ebrahiem M. Babiker ◽  
Bekele Abeyo ◽  
...  

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, can cause severe yield losses on susceptible wheat varieties and cultivars. Although stem rust can be controlled by the use of genetic resistance, population dynamics of P. graminis f. sp. tritici can frequently lead to defeat of wheat stem rust resistance genes. P. graminis f. sp. tritici race TKTTF caused a severe epidemic in Ethiopia on Ug99-resistant ‘Digalu’ in 2013 and 2014. The gene Sr11 confers resistance to race TKTTF and is present in ‘Gabo 56’. We identified seven single-nucleotide polymorphism (SNP) markers linked to Sr11 from a cross between Gabo 56 and ‘Chinese Spring’ exploiting a 90K Infinium iSelect Custom beadchip. Five SNP markers were validated on a ‘Berkut’/‘Scalavatis’ population that segregated for Sr11, using KBioscience competitive allele-specific polymerase chain reaction (KASP) assays. Two of the SNP markers, KASP_6BL_IWB10724 and KASP_6BL_IWB72471, were predictive of Sr11 among wheat genetic stocks, cultivars, and breeding lines from North America, Ethiopia, and Pakistan. These markers can be utilized to select for Sr11 in wheat breeding and to detect the presence of Sr11 in uncharacterized germplasm.


1935 ◽  
Vol 13c (6) ◽  
pp. 355-357
Author(s):  
T. Johnson ◽  
O. Johnson

Analyses were made to determine the organic nitrogen content of immature and mature tissues of six wheat varieties at a stage of growth about a week prior to the emergence of the flag leaf. The immature tissues comprised the leaves folded within the uppermost sheaths, while the mature tissues were represented by the fully grown leaves of the upper half of the plants. In all the varieties the nitrogen content of the mature tissues was greater than that of the immature ones. The greater susceptibility of the younger tissues can not, therefore, be attributed to a higher organic nitrogen content.


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