Changes of primary and secondary metabolite fruit composition in chilli pepper as affected by the cultivation management and heterotic effects

Chilli pepper is one of the most popular spices and a major vegetable crop grown worldwide. As consumption rises, new cultivars must be introduced to reduce cultivation inputs while maintaining adequate quality standard. The objective of this study is to examine how distinct cultivation management strategies alongside crop stress conditions affect the variation of a broad range of metabolites in chillies. Selected parental lines and their half-diallel hybrids were evaluated in a soilless system under controlled conditions, water stress, nitrogen deficiency, and in an organic field trial across two seasons, encompassing a total of five growing environments. Significant changes in metabolite content were found among the genotypes grown in the different trials. The application of low inputs led to a general decrease of yield traits and increase of volatiles. Water stress raised the levels of soluble solids and capsaicinoids, while nitrogen shortage increased the content of carotenoids. The dissection of genotypic (G) and environmental growing conditions (E) effects revealed high G influence for the capsaicinoids, sugars and volatile esters, a strong E variation for yield, oxalic and citric acid, and a high G × E interaction for volatiles. The effect of heterosis was also investigated highlighting remarkable effects on the contents of capsaicinoids, carotenoids, organic acids and sugars upon application of water or nitrogen stress. Hybrid vigour has proved highly promising for obtaining genotypes with better performance and stability. The comprehensive study provides new clues on the strategies to adopt for breeding chillies for quality and the improvement of the consumer’s appreciation.