Genetic mapping and development of near-isogenic lines with genes conferring mutant phenotypes in Aegilops tauschii and synthetic hexaploid wheat

Abstract

Mutant genes conferring triple glume and ligulelessness were mapped in Aegilops tauschii (Coss.) Schmal. (2n = 2x = 14, DD genome), the D genome donor to common wheat (Triticum aestivum L., 2n = 6x = 42, BBAADD genome) using microsatellite probes. The trg (tr iple g lume) locus was linked (21.6 cM) with the Br t (B rittle r achis in Ae. tauschii) locus in an F2 population of Ae. tauschii G3489 (tough rachis mutant)/Triple Glume Mutant. The trg gene was 8.6 cM distal to marker Xwmc656 in chromosome 3DL. Ligulelessness was a dominant trait in Ae. tauschii. The Lg t (L i g uleless in Ae. t auschii) gene was 9.3 cM distal to marker Xbarc159 in chromosome 2DL in an F2 population of Ae. tauschii KU2126/Liguleless Mutant. Gene Iw2 for non-glaucousness was linked to Xbarc124 located in the distal part of chromosome 2DS. Near-isogenic lines Brittle-G3489 and Liguleless-G3489 were developed from crosses of G3489 with wild type (brittle rachis) and Liguleless Mutant by backcrossing to G3489. Six synthetic hexaploid lines were developed using two lines of durum and five lines of Ae. tauschii. When compared with SynW-3 (LD222/G3489), SynW-1 (LD222/Liguleless-G3489) was liguleless due to the dominant gene, Lg t . The rachides of SynW-3 (LD222/G3489) and SynW-4 (LD222/Brittle-G3489) were tough. Ligules were present in synthetics SynW-5 (ANW 12A/G3489) and SynW-6 (ANW 12A/KU2126) indicating that G3489 and KU2126 had Lg 2 gene on chromosome 2D. Lg 2 was flanked 21.4 cM proximally by Xbarc228 and 13.0 cM distally by Xgdm6 in chromosome 2DL in the F2 of ANK-33/Syn-W5.