Deep planting improved stem root growth, flower yield and quality of Lilium cultivars

ABSTRACT Lily species are considered one of the most important cut flowers worldwide. With annual production of 282 million flowers and total value of $200 million, lily is among the top five cut flower species auctioned in the international flower stock markets. The objective of this study was to assess the effect of different planting depths on morphology, physiology, root growth and flower quality of lilies. Three hybrid lilies [Lilium × elegans; Orienpet (‘Maytime’, white) and L.A. (‘Fangio’, pink and ‘Pavia’, yellow)] were used. Deep planting at 25 cm significantly improved total and stem root systems, stem diameter and leaf area. No significant differences were noticed between planting depths for plant height, chlorophyll content, and gas exchange (photosynthesis, stomatal conductance and transpiration). Flower quality variables, specifically, vase life from deep planting were higher in 25-cm compared to 5 and 15. The ‘Maytime’ cultivar had higher leaf area, total and stem roots, flower diameter, number of days to flowering, and brighter color (L*) while the ‘Fangio’ had higher leaf number per plant, more basal roots, flower number per plant, vase life, and red color coordinate (a*). Overall, our results revealed that lily growers can increase their lily flower quality by adopting the deep planting at 25 cm.