(go to KOMUGI Home) (go to WIS List) (go to NO.89 Contents)

Wheat Information Service
Number 89: 13-16 (1999)
Research article

Development of near-isogenic sets of derivatives with T1BL.1RS or 1B chromosome substitutions in bread wheat.

A. Mujeeb-Kazi, A. Cortes, V. Rosas, M.D.H.M. William, and R. Delgado

International Maize and Wheat Improvement Center (CIMMYT), Lisboa 27, Apartado Postal 6-641, 06600 Mexico, D.F., Mexico


Summary

Seventeen bread wheat (Triticum aestivum L.) cultivars homozygous for chromosome 1B or T1BL. 1RS were pollinated by diverse bread wheat cultivars to produce chromosome 1B, T1BL.1RS F1 heterozygotes. Each F1 combination was then pollinated by its respective bread wheat parent (maternal) to yield the first backcross (BC1) derivatives. Heterozygous 1B, T1BL.1RS plants were identified by a combination of electrophoresis and Giemsa C-banding. These BC1F1 heterozygotes were backcrossed further to their respective maternal bread wheat parents to yield BC2 derivatives, which were similarly advanced to BC7 and then self-pollinated. From the selfed progeny, plants homozygous for chromosome 1B and T1BL.1RS were identified biochemically and cytologically. We discuss here the utility of these germplasms and their uniqueness.

Key words: Bread wheat, T1BL.1RS translocation, Isogenic lines


Introduction

Bread wheats (Triticum aestivum L.) with the T1BL.1RS translocation have been of interest over the past two decades, and are globally utilized in bread wheat breeding programs (Lukaszewski 1990). The 1RS chromosome arm possesses four race-specific biotic stress resistant genes (McIntosh 1983), contributing to the crops wide adaptation and yield potential (Rajaram et al. 1983; Villareal et al. 1994). Approximately 55 percent of our bread wheat germplasm possesses the T1BL.1RS translocation, and global cultivation of such wheats exceeds five million hectares.

The superior agronomic performance of T1BL. 1RS wheats in comparison with 1B wheats has been an active study area, and has utilized various germplasm groups for experimentation. One such group comprised of several lines with the T1BL.1RS translocation or instead, with chromosome 1B. This set of germplasms developed by Mujeeb-Kazi et al. (1996) facilitated a stringent testing of the rye contribution in a near-isogenic cv. Seri M82 (Villareal et al. 1998). The need to evaluate the 1RS effect across several bread wheat genotypes led to our producing the presently reported near-isogenic germplasms for seventeen bread wheat cultivars in which chromosomes 1B or T1BL.1RS were replaced by T1BL.1RS or 1B respectively by a series of backcrosses.

-->Next

(go to KOMUGI Home) (go to WIS List) (go to NO.89 Contents)