Brittle rachis (Br) -
The mature spike rachis of wild emmer [Triticum
turgidum L. ssp. dicoccoides (Korn. ex Asch. and
Graebner) Thell.] disarticulates spontaneously between
each spikelet leading to the dispersion of wedge-type
diaspores. By contrast, the spike rachis of domesticated
emmer (Triticum turgidum L. ssp. turgidum) fails to
disarticulate and remains intact until it is harvested. This
major distinguishing feature between wild and domesticated
emmer wheat is controlled by two major genes, brittle
rachis 2 (Br-A1) and brittle rachis 3 (Br-B1)
on the short arms of chromosomes 3A and 3B, respectively. Because
of their biological and agricultural importance, we localized Br-A1 and Br-B1
on microsatellite marker-based linkage maps of chromosomes 3A and chromosome
3B, respectively
(Nalam et al. 2006).
Publications
Nalam, V.J., M.I. Vales, C.J.W. Watson, S.F. Kianian and O. Riera-Lizarazu. 2006. Map-based analysis of genes affecting the brittle rachis character in tetraploid wheat (Triticum turgidum L.). Theor. Appl. Genet. 112: 373–381.