Morphological Traits and Biochemical and Volatile Compound Composition along with Gene Expression Profiling in <i>Chrysanthemum morifolium</i> Ramat. Grown under Soil and Soil-Less Conditions

The present investigation corroborates the effect of different cultivation conditions (polyhouse soil and Dutch bucket soil-less) on morpho-physiological traits, biochemical content, volatile compound composition, and gene expression analysis in four different flower colors cultivars of Chrysanthemum morifolium (‘Meghna Orange’, ‘Aishwarya Yellow’, ‘Shanka White’, ‘Chandra Pink’). The results revealed that maximum performance in morphological traits such as plant height, leaf length, leaf width, and flower diameter was recorded in C. morifolium cultivars grown in soil-less conditions compared with soil cultivation. However, a marginal increase in the number of flowers per plant was observed in soil-cultivated cultivars. Further, the number of days to flowering was shortened in C. morifolium cultivars grown in soil-less conditions compared to plants grown in soil cultivation. The growth biomass of flowers, chlorophyll content of leaves, total carbohydrates, total sugar, and total carotenoids content of the flowers produced from soil-less cultivation were enhanced compared to that of soil cultivated flowers. However, a slight decrease in total phenolics, flavonoids, and antioxidant capacity was observed in flowers obtained from soil-less cultivation compared to the soil-cultivated ones. A total of 49 volatile compounds were identified in flowers, with eucalyptol being the predominant compound in C. morifolium produced under both cultivation systems. However, the total identified percentage of volatile compounds was the highest in soil-cultivated cultivars. Interestingly, the expression of differentially expressed genes involved in flavonoid biosynthesis, plant hormone signal transduction, and photosynthesis was higher in flowers cultivated under soil-less conditions compared to soil conditions.