Morphological characterization of kale populations from northwestern Spain

Crops belonging to the genus Brassica are widely grown in Galicia (northwestern Spain). Kales ( Brassica oleracea L. convar. acephala (DC.) Alef.) are one of the most important Brassica crops in this region where landraces are traditionally grown by farmers on small plots for either human or animal food. Fifteen kale populations from northwestern Spain were evaluated in two locations and two planting dates (early and late). The objectives were i) to study their morphological diversity, ii) to determine their relationships, and iii) to evaluate their morphological and agronomic characteristics that could be incorporated to breeding programs in the future. Significant differences were found among populations for all traits while genotype × environment interaction was not significant for most of them. Cluster and principal component analysis were performed to determine relationships among landraces and to obtain information on the usefulness of the characters for the definition of groups. The phenogram showed five groups, two groups including most of the populations and three small independent groups. Groups of landraces were associated with the geographical origin and with morphological differences among populations, mainly with the length of their vegetative phase: north and early populations (cluster A) and south and late populations (cluster B). Morphological diversity was higher in coastal populations than in inland populations. As conclusion, the populations evaluated in this work display a wide diversity of traits which enable us to select and combine some interesting landraces for important traits in order to obtain improved varieties.