Use of Botanical Varieties of Brassica oleracea L. in the Breeding of Forage Kale

At present, forage kale cultivars for feeding cattle and sheep are either open-pollinated ones from population-improvement schemes within suitable botanical varieties of Brassica oleracea or triple-cross hybrids from within or between botanical varieties, the only commercialised latter type being between marrow-stem kale and Brussels sprouts. Eight botanical varieties (15 cultivars) and 13 types of hybrids (50 hybrids) between them were produced and assessed for forage traits in SE Scotland in the early 1980s when there was government funding in Great Britain for such work (terminated in 1990). These previously unpublished results may now be of interest to a new generation of commercial forage brassica breeders. In addition to height and dry matter yield and content, quality traits, such as digestibility and antimetabolites, were assessed. The hybrids with marrow-stem kale as one parent varied in height, but combined a high-dry-matter yield with desirable quality traits for a forage crop. None was ideal and none had a superior combination of traits to the hybrids with Brussels sprouts. The hybrids between marrow-stem kale and January King cabbage were the shortest and a possible alternative to dwarf thousand-head kale. The results can be used to justify new forage brassica breeding programmes.