Statistical multivariate analysis of melon shape: A case study using near isogenic lines

Melon fruit shape is a complex character of high interest for the agrifood chain due to it represents, a critical factor to reduce mechanical damage, transportation costs and for designing new melon varieties to satisfy consumer's future needs. The aim of our melon project is to increase the knowledge on the genetics of fruit market and fruit quality traits. An Introgression Line population consisting of Near Isogenic Lines (NILs) derived from a cross between the Spanish cultivar 'Piel de Sapo' (PS) and an exotic Koran accession (PI 161375), each of them having a single introgression from PI 161375 into the PS background, was used to detect alleles of genes or QTLs controlling fruit traits. The morphological fruit traits that better discriminated NILs were length, diameter, and fruit shape (the ratio length divided by diameter). Useful indices derived from these variables were obtained by discriminant analysis. The practical discriminant power of principal component analysis or discriminant analysis was not improved by using additional variables as fruit weight, the rates between seed cavity or epidermal thickness and diameter, or fruit density. Round shaped or small-sized fruit were good characterized, particularly by discriminant or classical factor analysis. Melon fruit with these quantitative traits loci can be designed in order to satisfy consumer's needs and reduce mechanical damages during the agrifood chain.