An introgression on wheat chromosome 4DL in RL6077 (Thatcher*6/PI 250413) confers adult plant resistance to stripe rust and leaf rust (Lr67)
- 869 Downloads
Adult plant resistance (APR) to leaf rust and stripe rust derived from the wheat (Triticum aestivum L.) line PI250413 was previously identified in RL6077 (=Thatcher*6/PI250413). The leaf rust resistance gene in RL6077 is phenotypically similar to Lr34 which is located on chromosome 7D. It was previously hypothesized that the gene in RL6077 could be Lr34 translocated to another chromosome. Hybrids between RL6077 and Thatcher and between RL6077 and 7DS and 7DL ditelocentric stocks were examined for first meiotic metaphase pairing. RL6077 formed chain quadrivalents and trivalents relative to Thatcher and Chinese Spring; however both 7D telocentrics paired only as heteromorphic bivalents and never with the multivalents. Thus, chromosome 7D is not involved in any translocation carried by RL6077. A genome-wide scan of SSR markers detected an introgression from chromosome 4D of PI250413 transferred to RL6077 through five cycles of backcrossing to Thatcher. Haplotype analysis of lines from crosses of Thatcher × RL6077 and RL6058 (Thatcher*6/PI58548) × RL6077 showed highly significant associations between introgressed markers (including SSR marker cfd71) and leaf rust resistance. In a separate RL6077-derived population, APR to stripe rust was also tightly linked with cfd71 on chromosome 4DL. An allele survey of linked SSR markers cfd71 and cfd23 on a set of 247 wheat lines from diverse origins indicated that these markers can be used to select for the donor segment in most wheat backgrounds. Comparison of RL6077 with Thatcher in field trials showed no effect of the APR gene on important agronomic or quality traits. Since no other known Lr genes exist on chromosome 4DL, the APR gene in RL6077 has been assigned the name Lr67.
KeywordsLeaf Rust Rust Resistance Stripe Rust Pollen Mother Cell Adult Plant Resistance
We acknowledge the excellent technical assistance of Pat Seto-Goh, Mira Popovic, Erica Riedel and Denis Green in Canada and Jessica Hyles and Keshab Kandel in Australia. We also thank the Grains Research and Development Corportion (GRDC), Australia for financial support.
- American Association of Cereal Chemists (2000) Approved methods of the AACC, 10th edn. The Association, St. PaulGoogle Scholar
- Dyck PL (1987) The association of a gene for leaf rust resistance with the chromosome 7D suppressor of stem rust resistance in common wheat. Genome 29:467–469Google Scholar
- Lillemo M, Singh RP, Huerta-Espino J, Chen XM, He ZH, Brown JKM (2007) Leaf rust resistance gene Lr34 is involved in powdery mildew resistance of CIMMYT bread wheat line Saar. In: Buck HT et al (eds) Wheat production in stressed environments. Springer, The Netherlands, pp 97–102CrossRefGoogle Scholar
- McIntosh RA, Wellings CR, Park RF (1995) Wheat rusts: an atlas of resistance genes. CSIRO Publications, East MelbourneGoogle Scholar
- Pallotta MA, Warner P, Fox RL, Kuchel H, Jefferies SJ, Langridge P (2003) Marker assisted wheat breeding in the southern region of Australia. In: Pogna NE, Romano M, Pogna EA, Galerio G (eds) Proceedings of 10th international wheat genetics symposium. Institutio Sperimentale per la Cerealcoltura, Rome, pp 789–791Google Scholar
- Peterson RF, Campbell AB, Hannah AE (1948) A diagrammatic scale for estimating rust intensity on leaves and stems of cereals. Can J Res 26:496–500Google Scholar
- Samborski DJ (1985) Wheat leaf rust. In: Roelfs AP, Bushnell WR (eds) The cereal rusts, vol 2. Academic Press, Orlando, pp 39–59Google Scholar
- Spielmeyer W, Singh RP, McFadden H, Wellings CR, Huerta-Espino J, Kong X, Appels R, Lagudah ES (2008) Fine scale genetic and physical mapping using interstitial deletion mutants of Lr34/Yr18: a disease resistance locus effective against multiple pathogens in wheat. Theor Appl Genet 116:481–490CrossRefPubMedGoogle Scholar