(go to KOMUGI Home) (go to WIS List) (go to NO.92 Contents)

---

Wheat Information Service
Number 92: 12-16 (2001)
Research article

Suppression of rust resistance genes from distantly related species in Triticum durum-Aegilops amphiploids

M. Aghaee-Sarbarzeh, H. S. Dhaliwal, P. Chhuneja and Harjit-Singh

Department of Genetics and Biotechnology, Punjab Agricultural University, Ludhiana 141 004, India


Summary

To transfer resistance gene(s) from non-progenitor diploid wild species, Aegilops caudata (CC) and Ae. umbellulatla (UU), amphiploids were developed from their crosses with susceptible Triticum durum cultivars. These amphiploids were subsequently backerossed to hexaploid wheat cv. Chinese Spring (CS). Most of the gene(s) conditioning leaf rust and stripe rust resistance from C and U genomes under the field condition were suppressed by A and/or B genomes of Triticum durum in the amphiploids whereas only a few of the resistance genes were expressed in the amphiploids at the seedling stage. Differential suppression of the genes in the amphiploids at seedling stage indicated the selective specificity of the suppression system. Recovery of resistant plants in F₂, F₃ and backcross generations of all amphiploids with CS at seedling stage and under field conditions indicated the absence of suppressor genes in Chinese Spring for these resistance genes.

Key words: Triticum aestivum, Aegilops caudata, Ae. umbellulata, rust resistance, suppression


Introduction

Related wild progenitor and non-progenitor species of wheat represent a large reservoir of useful variability that can be exploited for wheat improvement. Wide hybridization has contributed significantly to germplasm enhancement of bread wheat. Many agronomically important traits, including resistance to diseases and pests, and abiotic stresses have been transferred from related species and genera into wheat (Knott and Dvorak 1976; Sharma and Gill 1983; Gale and Miller 1987; Jiang et al. 1994; Friebe et al. 1996) and exploited commercially. The alien resistance genes are useful only when they are expressed in the cultivated background. Genetic suppression of disease resistance of related species by D genome has frequently been reported (Kerber 1983; Bai and Knott 1992; Dhaliwal et al. 1993; Innes and Kerber 1994; Ma et al. 1997).

Studies at the Punjab Agricultural University (PAU), Ludhiana has shown that among less closely related wild species, diploid Aegilops species with C, U and M genomes are excellent sources of resistance to leaf rust and stripe rust (Dhaliwal et al. 1993; Harjit-Singh and Dhaliwal 2000). Therefore, a study was initiated to transfer the rust resistance gene(s) from these species into hexaploid wheat. The present paper reports the suppression of resistance gene(s) of C and U genomes of Ae. caudata and Ae. umbellulata, respectively, by gene(s) on A and/or B genomes of durum wheat.

-->Next

(go to KOMUGI Home) (go to WIS List) (go to NO.92 Contents)