Agronomical and Morphological Diversity of Carob (Ceratonia Siliqua L.) Cultivars: A Case of a Semi-arid Region in Majorca (Spain)

Abstract There is an increasing awareness of the potential usefulness of the carob tree (Ceratonia siliqua L.) as a crop, due to its adaptability to agriculture in marginal lands and its capacity to confront foreseeable adverse climatic conditions. Moreover, in the food industry there is an increasing interest in this fruit as a functional ingredient, due to its physicochemical components and nutritional benefits. The species is traditionally cultivated in the Mediterranean region and a wide range of carob cultivars have been developed. The present work aims to evaluate yield and morphological pod and seed characteristics from 9 different cultivars from Majorca (Spain). Statistically significant differences were found among the cultivars for the characteristics examined, indicating a high genetic diversity. A correlation analysis between yield and morphological parameters exhibited a negative correlation between seed yield and pod width, length, weight and thickness; a positive correlation of pod weight with pod length, width and thickness, and negative correlation between seed weight and carob sex. The Principal Component Analysis (PCA) was applied in order to separate the different carob cultivars and establish three main groups. In the first of them, a great phenotypic diversity is evident. A two-dimensional model was found to be significant and explained 77.66% of the observed variability, the first component being mainly dominated by pod characteristics and seed yield (57.72%) and the second component mainly by seed parameters (19.94%).