The transfer and characterization of resistance to common root rot from Thinopyrum ponticum to wheat

Abstract

Common root rot, caused by Cochliobolus sativus (Ito and Kurib) Drechs. ex Dastur, is a major soil-borne disease of spring and winter wheat (Triticum aestivum L. em Thell.) on the Canadian prairies. Resistance to common root rot from Thinopyrum ponticum (Podp.) Liu and Wang was transferred into wheat via crossing with Agrotana, a resistant wheat - Th. ponticum partial amphiploid line. Evaluation of common root rot reactions showed that selected advanced lines with blue kernel color derived from a wheat x Agrotana cross expressed more resistance than the susceptible T. aestivum 'Chinese Spring' parent and other susceptible wheat check cultivars. Cytological examination revealed 41 to 44 chromosomes in the advanced lines. Genomic in situ hybridization, using total genomic DNA from Pseudoroegneria strigosa (M. Bieb) A. Löve (St genome) as a probe, demonstrated that the blue kernel plants had two pairs of spontaneously translocated J-Js and Js-J chromosomes derived from the J and Js genome of Th. ponticum. The presence of these translocated chromosomes was associated with increased resistance of wheat to common root rot. The lines with blue aleurone color always had a subcentromeric Js-J translocated chromosome. The subtelocentric J-Js translocated chromosome was not responsible for the blue kernel color. The genomic in situ hybridization analysis on meiosis revealed that the two spontaneous translocations were not reciprocal translocations.

Resistance to soil-borne diseases of wheat: Contributions from the wheatgrasses Thinopyrum intermedium and Th. ponticum

“…However, the highest level of root rot resistance in the advanced generation lines was associated with the presence of both translocated chromosomes. Only a few of the advanced breeding lines expressed the same level of root rot resistance as that observed in Agrotana and none surpassed it (Li et al 2004b).…”

“…ponticum (Chen et al 1998a). By crossing Chinese Spring with Agrotana, a large number of progeny lines were developed, which permitted the transfer of resistance to common root rot into wheat (Li et al 2004b).…”

“…Crosses were made with the cultivar Chinese Spring to transfer root rot resistance from Agrotana into a wheat background with improved agronomic traits and to identify the chromosomal location(s) of the resistance gene(s) (Li et al 2004b). Advanced generation lines (F 8 and F 11 ) with red and blue kernel color from the cross were evaluated for their root rot reactions and resistance.…”

“…Although superior resistance was observed in derivatives of Agrotana (Li et al 2004b), linkage of the alien chromosomes with adverse quality and agronomic traits restricts their use in wheat improvement programs. demonstrated that blue kernel color is not always associated with root rot resistance, which suggests that red kernel-colored lines with high levels of root rot resistance might be obtained.…”

Genetic diversity of Tunisian accessions ofAegilops geniculataRoth and durum wheats (Triticum durumDesf.) using RAPD markers

“…An inter-specific similarity was observed by a low of 52.2% for the two closely related species. This result reflects the fact that they have divergence in their genetic characteristics, while hybridisation between them for wheat improvement has brought the two species closer genetically (Martin-Sanchez et al, 2003;Li et al, 2004). Moreover, Kimber and Feldman (1987) noticed that durum and bread wheat are products of natural hybridization of perennial wild types.…”