Dissection of heterotic, genotypic and environmental factors influencing the variation of yield components and health-related compounds in chilli pepper (Capsicum annuum)

Chilli pepper is a widely spread vegetable crop and one of the main spices used all over the world. Its properties comprise high antioxidant capacity and content of several healthy-related compounds including vitamin C, carotenoids and capsaicinoids. In countries of the Mediterranean basin, chilli production is largely based on local varieties traditionally selected for open field conditions, although, the genetic improvement is a rapidly growing sector toward the development of hybrids. In the present study, nine chilli pepper varieties with diverse market destinations including powder consumption, canned production, and blister packaging as well as seven hybrids obtained through half-diallel crosses between the parent varieties were grown in replicated field trials over diverse locations and evaluated in a comprehensive approach regarding twenty-six quantitative agronomic, morphological and health-related phytochemical traits. Significant differences between hybrids and parents were found for 12 out of the 26 traits studied in both environments. Agronomic and chemical traits did not differ significantly except than for total yield and pH. Several biochemical traits differed significantly and carotenoids and ascorbic acid values were mostly linked to the cultivation environment. A significant effect of the genotype (P < 0.01) was found in all traits for both parental lines and hybrids. The phenotypic plasticity revealed high stability for fruit morphological traits in both parents and hybrids. Greater plasticity was found for total yield in the parent lines, while hybrids were more stable for capsaicinoids and more plastic for carotenoids and AsA, compared to parental. Significant mid-parent heterosis was observed in all the hybrids tested for at least one of the trait evaluated. The PCA in the first two dimensions explained 48.26% of the total variance showing a distinction between each hybrid and the related parental lines for the traits analyzed. This comprehensive approach used, allow to dissect those traits which can be successfully introgressed in hybrids and are useful for precision breeding of novel varieties.