Cytogenetically Engineered Rye Chromosomes 1R to Improve Bread‐making Quality of Hexaploid Triticale

Abstract

Hexaploid triticale (X Triticosecale Wittmack) is rarely used for human consumption because of its poor bread‐making quality. To create the genetic potential for bread‐making quality similar to that of bread wheat (Triticum aestivum L), rye (Secale cereale L.) chromosome 1R in triticale cv. Presto was cytogenetically engineered to remove secalin loci Sec‐1 and Sec‐3, and to introduce wheat storage protein loci Gli‐1 and Glu‐1 The manipulations were by homoeologous recombination between rye chromosome 1R and 1B or 1D of wheat, followed by homologous recombination of primary recombinants with translocation breakpoints in desired locations. This approach generated three classes of multi‐breakpoint translocation chromosomes named Valdy, FC and RM. Chromosome Valdy is a three breakpoint translocation with loci Gli‐D1, Sec‐1 and Glu‐D1; chromosomes FC1 and FC2 are five breakpoint translocations with loci Gli‐D1 and Glu‐D1, and chromosomes RM are six breakpoint translocations with loci Gli‐B1 and Glu‐D1 Preliminary tests of the effects of these chromosomes show a 230 to 250% increase of the SDS‐sedimentation value over the recipient triticale Presto. While the impact of these chromosomes on the agronomic value of triticale is not clear, they restore to triticale the genetic load of gluten‐encoding loci similar to that of bread wheat, thereby creating the genetic potential for breeding bread‐making triticales.