Deletion mapping by gametocidal genes in common wheat: position of speltoid suppression (Q) and β-amylase (β-Amy-A2) genes on chromosome 5A

Abstract

The genes for speltoid suppression (Q) and β-amylase (β-Amy-A2) in common wheat (Triticum aestivum) were mapped cytologically on the long arm of chromosome 5A by using four 5Aq deletion lines produced by the action of gametocidal genes of Aegilops speltoides. A line with 13% terminal deletion in the whole long arm lacked both β-Amy-A2 and Q, indicating that these genes are confined within the terminal area. According to the genetic map, four other genes distal to β-Amy-A2, B1 (awn suppression), Hn (hairy node), Vrn1 (vernalization), and Kr2 (crossability), must also exist in this 13% terminal area. The β-Amy-A2 gene is mapped at 20 centimorgans (cM) from the centromere, and map distance between β-Amy-A2 and Kr2 is estimated at 97.5 cM. A comparison of the cytological map drawn by the present deletion analysis with the genetic map based on the recombination values indicates that recombination is restricted to the proximal region of chromosome 5A.Key words: Triticum aestivum, gametocidal genes, cytological map, genetic map, deletion mapping.