The inheritance of adult plant resistance to stem rust derived from wheat cultivars Bonza and Chris

1997 ◽  
Vol 77 (2) ◽  
pp. 289-292
Author(s):  
D. R. Knott
Keyword(s):  
Triticum Aestivum ◽  
Plant Resistance ◽  
Stem Rust ◽  
Adult Plant Resistance ◽  
Complex Mixture ◽  
Recessive Gene ◽  
Triticum Aestivum L ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Recessive Genes

The wheat (Triticum aestivum L.) cultivars Bonza and Chris have adult plant resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) in addition to genes for specific resistance. Both cultivars were crossed to a susceptible wheat, LMPG. Lines carrying the adult plant resistances of the two parents were produced by selecting for seedling susceptibility in the greenhouse and adult plant resistance in the field to race 15B-1 (TMH). Three homozygous lines derived from Bonza and two from Chris were crossed and backcrossed to LMPG. Backcross F2 families were grown in a field nursery inoculated with a multi-race mixture of eight stem rust isolates including 15B-1. Stem rust severities in percent were recorded. An analysis of the data indicated that adult plant resistance of Bonza was controlled by a single recessive gene and that of Chris by two complementary recessive genes. Since the resistance was effective against a complex mixture of virulent stem rust races, it should be of interest to wheat breeders. Key words: Stem rust, Puccinia graminis, common wheat, Triticum aestivum, adult plant resistance

Inheritance of resistance to stem rust in 'Bonza', 'Chris', 'FKN-II-50-17', 'MRFY', 'Thatcher', 'Marquillo', and 'Hope' wheats

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 269-276
Author(s):  
M. Padidam ◽  
D. R. Knott
Keyword(s):  
Triticum Aestivum ◽  
Plant Resistance ◽  
Stem Rust ◽  
Adult Plant Resistance ◽  
Major Gene ◽  
Triticum Aestivum L ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Seedling Resistance ◽  
Minor Genes

Resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks, and Henn.), particularly adult plant resisitance to race 15B-1, was studied in seven wheat (Triticum aestivum L.) cultivars or lines: 'Bonza', 'Chris', 'FKN-II-50-17', 'MRFY', 'Thatcher', 'Marquillo', and 'Hope'. Each of the seven was crossed with a susceptible parent and either F4- or F5-derived lines developed by single seed descent. All of the lines were tested with race 15B-1 in field nurseries. Lines derived from parents carrying seedling resistance to race 15B-1 were also tested as seedlings in the greenhouse with race 15B-1, and in some cases races 56, 29, and C65. The data indicated that 'Bonza' carries Sr6, probably Sr5, an unidentified gene giving resistance to race 56, two unidentified genes for resistance to race C65, and two minor genes that combine to produce intermediate adult plant resistance. 'Chris' carries Sr5, Sr7a, Sr8a, and Sr12. In addition, it may have three minor genes for adult plant resistance. 'FKN-II-50-17' carries Sr6 and may have four minor genes that combine to produce moderate adult plant resistance. 'MRFY', which is seedling susceptible to race 15B-1, carries Sr9b, possibly Sr5, plus an unidentified gene for resistance to C65. In addition, it appears to have one major gene for adult plant resistance plus two or more minor genes. 'Thatcher', 'Marquillo', and 'Hope' had only limited resistance to race 15B-1 in the field and no genetic analysis of their crosses was possible. The four parents that had good resistance to race 15B-1 in the field, 'Bonza', 'Chris', 'FKN-II-50-17', and 'MRFY', all carry minor genes for adult plant resistance that had little effect individually but produced moderate resistance when combined. The genes Sr5 and Sr9b, which have no effect on resistance to 15B-1 is seedlings, were found to significantly increase resistance in adult plants in the field.Key words: stem rust, Puccinia graminis tritici, wheat, Triticum aestivum, adult plant rust resistance.

Inheritance of resistance to stem rust in six wheat lines having adult plant resistance

Genome ◽  
1988 ◽  
Vol 30 (3) ◽  
pp. 283-288 ◽  
Author(s):  
D. R. Knott ◽  
M. Padidam
Keyword(s):  
Triticum Aestivum ◽  
Plant Resistance ◽  
Stem Rust ◽  
Adult Plant Resistance ◽  
Descent Method ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Inheritance Of Resistance ◽  
Seedling Resistance ◽  
Resistant Parent

Inheritance of resistance to race 15B-1 of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks, and Henn.) was studied in six lines of wheat (Triticum aestivum L.) having adult plant resistance. The six lines were crossed to a susceptible line and the progenies were advanced to the F5 generation by the single seed descent method. From 91 to 135 F5-derived F7 lines from each cross were tested with race 15B-1 in field nurseries and selected lines were tested in a multirace nursery. The number of genes controlling resistance was estimated by grouping the F7 lines into those as resistant as the resistant parent and other lines, and testing against the ratios expected with various numbers of genes. In 1982, for all six crosses, the segregations fit best to either three- or four-gene ratios. The mean rust severities for the F7 lines in each cross were concentrated at the susceptible end of the distribution. Apparently the genes for resistance had small effects that were multiplicative rather than additive. Under lighter epiphytotics in 1983 and 1984, additional F7 lines were classified as resistant as the resistant parents. The F7 lines were generally more resistant to the multirace mixture than to race 15B-1. The resistant parents probably carried genes for specific seedling resistance to some of the races but in some cases may have carried additional genes for adult plant resistance.Key words: stem rust, Puccinia graminis tritici, wheat, Triticum aestivum, adult plant resistance.

The field reaction to stem rust of 'Chinese Spring' substitution lines carrying chromosomes from 'Hope' and 'Thatcher' wheats

1986 ◽  
Vol 28 (1) ◽  
pp. 12-16
Author(s):  
D. R. Knott
Keyword(s):  
Stem Rust ◽  
Chinese Spring ◽  
Rust Resistance ◽  
Adult Plant Resistance ◽  
Triticum Aestivum L ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Substitution Lines ◽  
Field Reaction ◽  
Rust Severity

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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