ex Müntzing Triticale (/trɪtɪˈkeɪliː/; × Triticosecale) is a hybrid of wheat (Triticum) and rye (Secale) first bred in laboratories during the late 19th century in Scotland and Germany.

As a rule, triticale combines the yield potential and grain quality of wheat with the disease and environmental tolerance (including soil conditions) of rye.

In 1873, Alexander Wilson first managed to manually fertilize the female organs of wheat flowers[9] with rye pollen (male gametes), but found that the resulting plants were sterile, much the way the offspring of a horse and donkey is an infertile mule.

In that year, it was discovered that the chemical colchicine, which is used both for general plant germination and as a treatment for gout, would force chromosome doubling by keeping them from pulling apart during cell division.

Earlier triticale hybrids had four reproductive disorders, namely meiotic instability, high aneuploid frequency, low fertility and shriveled seed (Muntzing 1939; Krolow 1966).

Earlier research conducted by CIMMYT made use of a chemical hybridising agent to evaluate heterosis in hexaploid triticale hybrids.

The prediction of general combining ability of any triticale plant from the performance of its parents is only moderate with respect to grain yield.

Commercially exploitable yield advantages of hybrid triticale cultivars is dependent on improving parent heterosis and on advances in inbred-line development.

(Gallais 1984)[24] Lodging (the toppling over of the plant stem, especially under windy conditions) resistance is a polygenically inherited (expression is controlled by many genes) trait, and has thus been an important breeding aim in the past.

[dubious – discuss] R-genes are generally introduced within such blocks, which are usually incorporated/translocated/introgressed into the distal (extreme) regions of chromosomes of the crop being introgressed.

Genes located in the proximal areas of chromosomes may be completely linked (very closely spaced), thus preventing or severely hampering recombination, which is necessary to incorporate such blocks.

The resultant translocation of smaller blocks that indeed carry the R-gene(s) of interest has decreased the probability of introducing unwanted genes.

[37][42][43] Chromosome elimination is another method of producing DHs, and involves hybridisation of wheat with maize (Zea mays L.), followed by auxin treatment and the artificial rescue of the resultant haploid embryos before they naturally abort.

[44] Its success is in large part due to the insensitivity of maize pollen to the crossability inhibitor genes known as Kr1 and Kr2 that are expressed in the floral style of many wheat cultivars.

The identification of good combining ability at an early stage in the breeding programme can reduce the costs associated with 'carrying' a large number of plants (literally thousands) through it, and thus forms part of efficient selection.

Combining ability is assessed by taking into consideration all available information on descent (genetic relatedness), morphology, qualitative (simply inherited) traits and biochemical and molecular markers.

They are popular tools in genetics and breeding because of their relative abundance compared to other marker types, a high degree of polymorphism (number of variants), and easy assaying by polymerase chain reaction.

Comparative genome mapping has revealed a high degree of similarity in terms of sequence colinearity between closely related crop species.

[52] Transferability refers to the phenomenon where the sequence of DNA nucleotides flanking the SSR locus (position on the chromosome) is sufficiently homologous (similar) between genomes of closely related species.

[52] The genetic transformation of crops involves the incorporation of 'foreign' genes or, rather, very small DNA fragments compared to introgression discussed earlier.

[53] Little has been documented on Agrobacterium-mediated transformation of wheat: while no data existed with respect to triticale until 2005, the success rate in later work was nevertheless low.

Conventional plant breeding has helped establish triticale as a valuable crop, especially where conditions are less favourable for wheat cultivation.

Triticale being a synthesized grain notwithstanding, many initial limitations, such as an inability to reproduce due to infertility and seed shrivelling, low yield and poor nutritional value, have been largely eliminated.

Many molecular markers can be applied to marker-assisted gene transfer, but the expression of R-genes in the new genetic background of triticale remains to be investigated.

[52] Another type of molecular marker, single nucleotide polymorphism (SNP), is likely to have a significant impact on the future of triticale breeding.

[55] An episode of the popular TV series Star Trek, "The Trouble with Tribbles", revolved around the protection of a grain developed from triticale.

This grain was named "quadro-triticale" by writer David Gerrold at the suggestion of producer Gene Coon, with four distinct lobes per kernel.

Early breeding efforts concentrated on developing a high-yield, drought-tolerant human food crop species suitable for marginal wheat-producing areas.

[58]) A later episode titled "More Tribbles, More Troubles", in the animated series, also written by Gerrold, dealt with "quinto-triticale", an improvement on the original, having apparently five lobes per kernel.

[59] Three decades later the spinoff series Star Trek: Deep Space Nine revisited quadro-triticale and the depredations of the Tribbles in the episode "Trials and Tribble-ations".