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- Title
Gene effect on partial resistance response to Puccinia triticina in perspective Romanian lines.
- Authors
Ittu, Mariana; Ciuca, Matilda; Marinciu, Cristina Mihaela; Voica, Maria; Banateanu, Cecilia; Ittu, Gheorghe
- Abstract
Leaf rust caused by Puccinia triticina Erikss. (Pt) is the most prevalent and damaging rust disease of wheat globally. Regular impact on yield is the result of premature leaf senescence and poorly developed kernels. Cultivars that deploy major resistance genes that operate qualitatively on a gene-for-gene pattern are widely used for disease control. Therefore, in practice, their effectiveness proved to be often short under the continuous and dynamic evolution of pathogen virulence. Adult plant slow-rusting partial resistance, quantitatively expressed in terms of a slower rate of disease progress and less spore production comparatively to qualitative resistance, has proven to be more durable, while a cultivar possessing it is widely cultivated under pathogen pressure. The cumulative effect of slow rust traits result and could be quantified by a smaller area under disease progress curve (AUDPC) and lower values of the final disease severity (FS,%), when resistant and susceptible cultivars are compared. Among the >70 genes catalogued as conferring plant resistance to Pt, at least four slow-rusting adult plant resistance genes (APR) have been designated to date: Lr34, Lr46, Lr67 and Lr68 while their additive and pleiotropic effects on other rusts and powdery mildew are better documented. In the wheat breeding program carried out at NARDI Fundulea, the development of new germplasm with more durable and multiple resistance to diseases, even partial, conferred by such genes is of great concern. In this respect were developed six populations for each of the APR genes Lr34, Lr46 and Lr67, derived from crosses with two adapted Romanian varieties, Glosa and Miranda, widely cultivated and appreciated by farmers. The presence of the targeted slow rusting resistance genes has been performed by molecular analyses with functional markers: cssfr5 (Lr34), csLV46/TaqI (Lr46) and Lr67PLUSHSUTF/R, Lr67HSPSUTF/R (Lr67). As a result, the 400 F6RILs were classified as i) non gene carriers, ii) single gene carriers and iii) carriers of combinations of two genes (Lr34/Lr46 and Lr34/ Lr67). In order to evaluate the individual effect of the APR genes on resistance to Pt, parents and all recombinant lines were phenotipically evaluated under controlled inoculation in three field environments: Fundulea (44°27'N/ 26°30'E), Albota (44°46'N/ 24°49'E) and Livada (47°87'N/ 23°13'E). Susceptible spreader rows planted as borders were inoculated with prevalent local P.t. isolates. Disease severity (DS) and host response to infection in each line were three times recorded, based on the modified Cobb Scale (Peterson, 1948) and Roelfs et al. (1992), respectively. According to AUDPC and RAUDPC (as % of the AUDPC values in the susceptible spreader), calculated for each line, significant differences between non and carriers of Lr genes were found as well as between single gene carriers. The mean lower values for the both criteria were found in lines carrying the pyramidated Lr34/Lr46 genes, derived from cross with Glosa: AUDPC = 427 and RAUDPC = 46%, suggesting their additive effect on slow rusting, as compared to this of each gene, separately and with combination of the Lr34/Lr67 genes. Lr34 gene proved a higher efficiency on slow rusting traits irrespective of the analysed background, in comparison to Lr46 and mainly with Lr67 gene that show a weaker effect on this type of resistance. Further investigations aimed to clarify the interaction environment/slow rusting response to P.t. in the Romanian perspective lines are necessary.
- Subjects
PUCCINIA triticina; GENETICS of disease resistance of plants; PLANT genes
- Publication
Cereal Research Communications, 2017, Vol 45, p84
- ISSN
0133-3720
- Publication type
Abstract
- DOI
10.1556/0806.45.2017.100