Characteristics and Seed Production of Italian and Iberian Type of Kale (Brassica oleracea var. acephala) Grown in Sicily

Kale is an underutilized crop which seems to be the first result of the domestication process of Brassica oleracea wild type complex (n=9). This crop is still grown in all European countries in home gardens and peri-urban vegetable farms and is appreciated for its rusticity and the high content of bioactive compounds. Kale leaves, in fact, contain high amounts of total polyphenols, ascorbic acid and glucosinolates. Seed production is important for a wide range of vegetable crops and its development depends upon many factors such as the genetic profile and physiological and environmental conditions. An important prerequisite for the successful production of seeds is the optimal timing of harvest. In view to enhance kale production and provide to growers qualified genotypes, attention was paid to the evaluation of twenty-three types of kale grown on the Italian and Iberian peninsulas for seed production which were compared to four commercial cultivars. Besides seed production, in the experiment plant characterization, according to the main IBPGRI descriptors, was performed. Seeds were sown in seedling trays and were transplanted when they had 4-5 expanded leaves. An experimental field (following a density of 2 plants m-2) was carried out with the aim to determine seed yields. The experimental design was a splitplot with three replicates. Siliquas were collected from ten plants for each replicas when the seeds reached their physiological maturity. Seed production showed significant differences among the compared genotypes; it varied from 0.59 q ha-1 to 25.69 q ha-1 respectively for one Italian and one Iberian types; the Italian landraces showed to be more productive. Plant characterization highlighted allowed to highlight the descriptors which appeared more discriminating such as plant shape, as well as several leaf and petiole traits.