Abstract only

Wheat drought-suitable lines should be semi-dwarf with long coleoptiles, resistant to multiple diseases, have good dough properties, and have productive tillers. To achieve this, nine target alleles need to be combined into one genotype. Three parent lines were used: Sunstate, a commercial Australian line; HM14BS, a germplasm line combining an allele for height reduction and long coleoptiles; and Silverstar+tin, a derivative of Silverstar with a restricted tillering allele. The largest target genotype frequency was found in the Silverstar+tin/HM14BS//Sunstate topcross. The optimum MAS strategy to combine the nine target alleles from this topcross could be divided into three steps: (i) selection for Rht-B1a and Glu-B1i homozygotes, and enrichment selection of Rht8c, Cre1, and tin in TCF1, (ii) selection of homozygotes for one target allele, e.g. Rht8c, and enrich the remaining target alleles in TCF2, and (iii) selection of the target genotype with doubled haploid lines or recombination inbred lines. Enrichment of allelic frequencies in TCF2 reduced the total number of lines screened from >3500 to <600. While eight target alleles were present at frequencies after selection, the tin reduced-tillering allele frequency was lower due to its strong repulsion-phase linkage to Glu-A3 and the incomplete linkage of the tin marker. Therefore, the presence of the tin gene needs to be further confirmed by other methods.

Genetic Resources Program

English

Lucia Segura

INT2542

CIMMYT Staff Publications Collection