Changes in chlorophyll and carotenoid content in oats associated with the expression of adult plant resistance to stem rust conferred by gene pg-11

1971 ◽  
Vol 49 (10) ◽  
pp. 1783-1785 ◽  
Author(s):  
D. E. Harder ◽  
J. W. Martens ◽  
R. I. H. McKenzie

The expression of adult plant oat stem rust resistance conferred by gene pg-11 is associated with a reduction of chlorophyll and carotenoid pigments in the leaf and stem tissue. Seedlings that possess gene pg-11 are susceptible to stem rust and have near normal pigment levels but with increasing age the pigment content decreases more rapidly than in plants without the gene and the plants become moderately resistant to stem rust. The ratio of chlorophyll to carotenoids remains unchanged at all stages of plant development. This gene has effects unlike any other known gene for stem rust resistance in oats.

2010 ◽  
Vol 61 (12) ◽  
pp. 1036 ◽  
Author(s):  
J. Zhang ◽  
C. R. Wellings ◽  
R. A. McIntosh ◽  
R. F. Park

Seedling resistances to stem rust, leaf rust and stripe rust were evaluated in the 37th International Triticale Screening Nursery, distributed by the International Wheat and Maize Improvement Centre (CIMMYT) in 2005. In stem rust tests, 12 and 69 of a total of 81 entries were postulated to carry Sr27 and SrSatu, respectively. When compared with previous studies of CIMMYT triticale nurseries distributed from 1980 to 1986 and 1991 to 1993, the results suggest a lack of expansion in the diversity of stem rust resistance. A total of 62 of 64 entries were resistant to five leaf rust pathotypes. In stripe rust tests, ~93% of the lines were postulated to carry Yr9 alone or in combination with other genes. The absence of Lr26 in these entries indicated that Yr9 and Lr26 are not genetically associated in triticale. A high proportion of nursery entries (63%) were postulated to carry an uncharacterised gene, YrJackie. The 13 lines resistant to stripe rust and the 62 entries resistant to leaf rust represent potentially useful sources of seedling resistance in developing new triticale cultivars. Field rust tests are needed to verify if seedling susceptible entries also carry adult plant resistance.


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.


Plant Disease ◽  
2021 ◽  
Author(s):  
Yahya Rauf ◽  
Prabin Bajgain ◽  
Matthew Rouse ◽  
Khalil A Khanzada ◽  
Sridhar Bhavani ◽  
...  

Adult plant resistance (APR) to wheat stem rust has been one of the approaches for resistance breeding since the evolution of the Ug99 race group and other races. This study was conducted to dissect and understand the genetic basis of APR to stem rust in spring wheat line ‘Copio’. A total of 176 recombinant inbred lines (RIL) from the cross of susceptible parent ‘Apav’ with Copio were phenotyped for stem rust resistance in six environments. Composite interval mapping (CIM) using 762 Genotyping-by-Sequencing (GBS) markers, identified 16 genomic regions conferring stem rust resistance. Assays with gene-linked molecular markers revealed that Copio carried known APR genes Sr2 and Lr46/Yr29/Sr58 in addition to the 2NS/2AS translocation that harbors race-specific genes Sr38, Lr37 and Yr17. Three QTL were mapped on chromosomes 2B, two QTL on chromosomes 3A, 3B, and 6A each, and one QTL on each of chromosomes 2A, 1B, 2D, 4B, 5D, 6D and 7A. The QTL QSr.umn.5D is potentially a new resistance gene and contributed to quantitative resistance in Copio. The RILs with allelic combinations of Sr2, Sr38, and Sr58 had 27-39% less stem rust coefficient of infection in all field environments compared to RILs with none of these genes and this gene combination was most effective in the US environments. We conclude that Copio carries several genes that provide both race-specific and non-race-specific resistance to diverse races of stem rust fungus and can be used by breeding programs in pyramiding other effective genes to develop durable resistance in wheat.


2014 ◽  
Vol 7 (3) ◽  
Author(s):  
Jessica E. Rutkoski ◽  
Jesse A. Poland ◽  
Ravi P. Singh ◽  
Julio Huerta‐Espino ◽  
Sridhar Bhavani ◽  
...  

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 530-537 ◽  
Author(s):  
E. R. Kerber ◽  
P. L. Dyck

A partially dominant gene for adult-plant leaf rust resistance together with a linked, partially dominant gene for stem rust resistance were transferred to the hexaploid wheat cultivar 'Marquis' from an amphiploid of Aegilops speltoides × Triticum monococcum by direct crossing and backcrossing. Pathological evidence indicated that the alien resistance genes were derived from Ae. speltoides. Differential transmission of the resistance genes through the male gametes occurred in hexaploid hybrids involving the resistant 'Marquis' stock and resulted in distorted segregation ratios. In heterozygotes, pairing between the chromosome arm with the alien segment and the corresponding arm of the normal wheat chromosome was greatly reduced. The apparent close linkage between the two resistance genes, 3 ± 1.07 crossover units, was misleading because of this decrease in pairing in the presence of the 5B diploidizing mechanism. The newly identified gene for adult-plant leaf rust resistance, located on chromosome 2B, is different from adult-plant resistance genes Lr12, Lr13, and Lr22 and from that in the hexaploid accession PI250413; it has been designated Lr35. It is not known whether the newly transferred gene for stem rust resistance differs from Sr32, also derived from Ae. speltoides and located on chromosomes 2B.Key words: hexaploid, Triticum, Aegilops, aneuploid, Puccinia graminis, Puccinia recondita.


Plant Disease ◽  
2021 ◽  
Author(s):  
Tianya Li ◽  
Yiwei Xu ◽  
Xue Zhang ◽  
Xian Xin Wu ◽  
Yazhao Zhang ◽  
...  

Oat stem rust, caused by Puccinia graminis f. sp. avenae (Pga), is one of the most devastating diseases of oat. The most cost-effective and eco-friendly strategy to control this disease is the use of resistant cultivars. However, P. graminis f. sp. avenae can overcome the resistance of cultivars by rapidly changing its virulence. Thus, information on the virulence of P. graminis f. sp. avenae populations and resistance of cultivars is critical to control the disease. The current study was conducted to monitor the virulence composition and dynamics in the P. graminis f. sp. avenae population in China and to evaluate resistance of oat cultivars. Oat leaves naturally infected by P. graminis f. sp. avenae were collected during 2018 and 2019 and 159 isolates were derived from single uredinia. The isolates were tested on 12 international differential lines, and eight races, TJJ, TBD, TJB, TJD, TJL, TJN, TGD, and TKN, were identified for the first time in China. The predominant race was TJD, virulent against Pg1, Pg2, Pg3, Pg4, Pg8, Pg9, and Pg15, accounting for 35.8% and 37.8% in 2018 and 2019, respectively. The sub-predominant races were TJN (30.2% in 2018, 28.3% in 2019) and TKN (20.8% in 2018, 12.3% in 2019). All isolates were virulent to Pg1, Pg2, Pg3, and Pg4, and avirulent to Pg6 and Pg16. The three predominant races (TJD, TJN, and TKN) were used to evaluate resistance in 30 Chinese oat cultivars at the seedling and adult-plant stages. Five cultivars, Bayan 1, Baiyan 2, Baiyan 3, Baiyan 5, and Baiyan 9, were highly resistant to the three races at both seedling and adult-plant stages. The results of the virulences and frequencies of P. graminis f. sp. avenae races and the resistant cultivars will be useful in understanding the pathogen migration and evolution and for breeding oat cultivars with stem rust resistance.


1986 ◽  
Vol 28 (1) ◽  
pp. 12-16
Author(s):  
D. R. Knott

Studies were done in an attempt to determine the inheritance of adult plant resistance to stem rust (Puccinia graminis f. sp. tritici Eriks. and E. Henn.) in the wheat (Triticum aestivum L.) cultivars 'Hope' and 'Thatcher'. 'Chinese Spring' substitution lines carrying individual chromosomes from 'Hope' and 'Thatcher' were tested in field rust nurseries, three times each with races 15B-1 and 56, and twice with multirace mixtures. In 1976 it was found that the date of heading often had a significant effect on rust severity, with early lines showing less rust. In 1977 and 1984 the lines were divided into three groups based on maturity and were planted on three dates about 10 days apart to make heading dates more uniform. The data indicate that 'Hope' has genes for resistance to race 56 on chromosomes 3B (Sr2) and 4D, and to a multirace mixture on 1B, 3B, and 7B. 'Thatcher' possibly has genes for resistance to race 56 on chromosomes 6A and 3B (Sr12). The results show that the resistance of both cultivars is complex and most genes have only small effects.Key words: Triticum, Puccinia, rust resistance, substitution lines.


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