Breeding Perennial Grain Crops Based on Wheat

Abstract

Wild relatives offer a diversity of traits potentially useful in crop improvement. Identification of major genes for resistance to biotic and abiotic stresses, in conjunction with targeted introgression, has introduced some of these traits into cultivated varieties. The difficulty of transferring complex traits, and associated linkage drag, has limited the ability of breeding programs to fully use important genetic variation. Wheat (Triticum L.) is an example of an important crop with large secondary and tertiary genepools of species capable of producing viable offspring by cross pollination. Wheat is annual, but most of the related species in the Triticeae Dumort tribe are perennials. An unknown number of genes control the perennial habit, although previous work has shown that it is a complex trait with quantitative expression. Lack of recombination between the parental genomes and complexity of the trait suggest another avenue for breeding: the addition of a genome. Multiple genera can hybridize with wheat, and some combinations produce stable amphiploids. The development of perennial grain and forage crops balancing the agronomics of wheat with the polycarpic habit of its relatives is promising. The approach is similar to Triticale (× Triticosecale Wittmack ex A. Camus), where new crops are developed combining the desirable qualities of the parents. Through prebreeding of the wild relatives, application of insight into meiosis, and strategic use of known genes, it should be more efficient to breed perennial grain crops adapted to diverse production systems.