Creating New Forms of Hexaploid Triticale Associating Complete R and D Genomes

TL;DR

Scientists created a new hexaploid triticale with a complete D genome from wheat and a mix of A and B genomes to improve its agricultural and technological properties.

Contribution

The novel hexaploid triticale combines complete D and R genomes with a mixed A/B genome to enhance genetic flexibility and breeding potential.

Findings

New hexaploid triticale lines were successfully created with a complete D genome from wheat and a complete R genome from rye.

The mixed genome of A and B wheat chromosomes allows for genetic flexibility and potential optimization.

These lines show agronomic stability and could improve triticale's technological and disease resistance traits.

Abstract

The aim of this work was to create a new type of hexaploid Triticale (2n = 6x = 42), possessing the complete D sub-genome of wheat (2n = 6x = 42, BB AA DD) originating from Aegilops tauschii, the complete sub-genome of rye (2n = 2x = 14, RR), and a mixogenome consisting of seven chromosome pairs derived from the A and B sub-genomes of wheat, in order to introduce new technological properties controlled by D genome, and genes for disease resistance into triticale.

Triticale, a man-made cereal, has been grown worldwide since the 1980s in order to replace established cereals in difficult areas, at least partially. The present cultivars are mostly hexaploid genotypes with 42 chromosomes, of genomic structure AA BB RR. Their agricultural performance does not meet all breeding requirements. In particular, some technological characteristics are inadequate compared to tetraploid (durum) and hexaploid (soft) wheats. Therefore, we aimed to find ways to improve modern triticale varieties by targeted introgression with genes and even chromosomes from wheat, in particular, from the D genome. Through appropriate bridge crossings and embryo culture technique and under cytogenetic control, a series of new stable hexaploid lines with reasonable agronomic stability were finally produced. All of them carried a complete D sub-genome, a complete R sub-genome, plus a mixed genome consisting of various combinations of chromosomes derived from the A and B genomes representing the seven homoeologous groups. It is clear that such mixed genomes can be of genetic and breeding significance. These large introgression lines demonstrate the flexibility of genome organization and offer the opportunity for further regulatory and genetic optimization.

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