Biochemical Studies on Leaf Spot and Flower Blight Caused by Alternaria tenuissima in Marigold

Marigold (Tagetes spp.) is a widely cultivated traditional flower crop in various regions of India, with significant commercial importance in South Gujarat. In this study, biochemical analysis was conducted on the leaves and flowers which infection of flower blight and leaf spot caused by Alternaría tenuissima of one resistant and one susceptible variety, selected from a screening experiment. The analysis measured total sugar, reducing sugar, total phenol, PAL, and PPO levels. It was observed that all biochemical components increased after infection. The findings suggested that the resistant variety, Gulzafri Yellow, exhibited lower levels of total and reducing sugars, but higher concentrations of total phenols, phenylalanine ammonia lyase(PAL) and polyphenol oxidase (PPO) which contributed to its resistance to the disease.