Chromatic Crescendo: Night light colours boost Chrysanthemum growth and bloom

This innovative study, conducted at the Research Farm, Department of Floriculture and Landscaping, Punjab Agricultural University, Ludhiana, from 2018 to 2019, investigated the effects of coloured LED night breaks on Chrysanthemum morifolium Ramat. growth and flowering. Ten diverse cultivars were subjected to red, green, and blue light treatments from mid-August to late October, followed by natural day length exposure. Our findings reveal a nuanced interplay between light colour and genotype, significantly influencing plant architecture, flowering dynamics, and pigment production. Red light emerged as a maestro of stem elongation, producing the tallest plants (mean height 100.97 cm), while blue light conducted a powerful performance in stem thickening (mean diameter 7.81 mm) and stomatal development (up to 54.66 stomata per mm²). Green light accelerated flowering, with bud appearance as early as 55.79 days in ‘Thai Chin Queen’. Vase life peaked at 17.57 days under red light for ‘Snow Ball’, while flower size reached 19.24 cm in ‘Snow Ball’ under blue light. Anthocyanin content was highest (2.19 mg g-1) in ‘Thai Chin Queen’ under blue light, and carotenoids peaked (97.18 mg g-1) in ‘Pusa Centenary’ under blue light. This research unveils the potential for tailored light recipes in chrysanthemum cultivation, promising enhanced control over growth, flowering, and quality traits. Our results pave the way for innovative, sustainable practices in ornamental horticulture, offering a spectrum of possibilities for precision floriculture.