Chromosome regions associated to stem rust resistance in durum wheat (Triticum durum Desf.) germplasm
Material type:
TextPublication details: Beijing (China) Chinese Academy of Agricultural Sciences : 2010Description: p. 151Summary: A panel of durum cultivars and advanced breeding lines (187 accessions in total) suitable for association mapping studies (Maccaferri et al., 2006) has been characterized for stem rust response in Ethiopia. Three dedicated field trials were carried out in main- and off-season under artificial inoculation with stem rust race Ug99 and a mixture of highly virulent Ethiopian races. The phenotype frequency distributions indicated that the genetic control of the disease response, in the germplasm collection herein considered is probably controlled by several genes/QTLs. Based on the means over seasons, eight accessions showed severity scores lower than 10% (i.e. high levels of resistance over seasons). An additional 16 genotypes exhibited promising levels of resistance (DSS between 10 and 20%). The molecular genotypes of the accessions at 186 simple sequence repeat (SSR) markers have been subjected to the association test with the phenotypic data, considering only allelic variants with frequency higher than 0.10. The association analysis was carried out using the general linear model (GLM) with estimates of population structure (based on 96 loosely linked markers) used as covariates. Several chromosome regions putatively involved in the genetic control of stem rust response were identified. Two chromosomal regions were significantly associated (P 0.05 experiment-wise significance threshold) with stem rust resistance: one on the long arm of chr. 1B near Sr14 and one on chrs. 2B near Sr28 and Sr9. Significant associations were also detected in other regions. Among the chr. regions that showed highly significant associations (P 0.01, marker-wise) while not harboring characterized Sr genes, it can be mention the distal portion of chrs. 1AS, 1BL, 2AL and 3AS and the centromeric portion of chr. 2AS. These results suggest that durum wheat resistance to the Ethiopian races of stem rust and to Ug99 is likely oligogenic and that there is potential to identify previously uncharacterized resistance genes of minor effect. The molecular markers tagging the favorable alleles could be valuable for marker-assisted breeding. At the Cereal Disease Laboratory (University of Minnesota), the accessions are being characterized for their seedling infection types with stem rust races TTKSK, TRTTF and TTTTF.
| Item type | Current library | Collection | Call number | Status | Date due | Barcode | Item holds | |
|---|---|---|---|---|---|---|---|---|
| Conference proceedings | CIMMYT Knowledge Center: John Woolston Library | CIMMYT Staff Publications Collection | CIS-6275 (Browse shelf(Opens below)) | Available |
Abstract only
A panel of durum cultivars and advanced breeding lines (187 accessions in total) suitable for association mapping studies (Maccaferri et al., 2006) has been characterized for stem rust response in Ethiopia. Three dedicated field trials were carried out in main- and off-season under artificial inoculation with stem rust race Ug99 and a mixture of highly virulent Ethiopian races. The phenotype frequency distributions indicated that the genetic control of the disease response, in the germplasm collection herein considered is probably controlled by several genes/QTLs. Based on the means over seasons, eight accessions showed severity scores lower than 10% (i.e. high levels of resistance over seasons). An additional 16 genotypes exhibited promising levels of resistance (DSS between 10 and 20%). The molecular genotypes of the accessions at 186 simple sequence repeat (SSR) markers have been subjected to the association test with the phenotypic data, considering only allelic variants with frequency higher than 0.10. The association analysis was carried out using the general linear model (GLM) with estimates of population structure (based on 96 loosely linked markers) used as covariates. Several chromosome regions putatively involved in the genetic control of stem rust response were identified. Two chromosomal regions were significantly associated (P 0.05 experiment-wise significance threshold) with stem rust resistance: one on the long arm of chr. 1B near Sr14 and one on chrs. 2B near Sr28 and Sr9. Significant associations were also detected in other regions. Among the chr. regions that showed highly significant associations (P 0.01, marker-wise) while not harboring characterized Sr genes, it can be mention the distal portion of chrs. 1AS, 1BL, 2AL and 3AS and the centromeric portion of chr. 2AS. These results suggest that durum wheat resistance to the Ethiopian races of stem rust and to Ug99 is likely oligogenic and that there is potential to identify previously uncharacterized resistance genes of minor effect. The molecular markers tagging the favorable alleles could be valuable for marker-assisted breeding. At the Cereal Disease Laboratory (University of Minnesota), the accessions are being characterized for their seedling infection types with stem rust races TTKSK, TRTTF and TTTTF.
Genetic Resources Program|Global Wheat Program
English
Lucia Segura
INT2585|CCJL01
CIMMYT Staff Publications Collection
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