The greenhouse tomato industry is characterised by its varietal diversity. Widely grown tomato types include beefsteak, tomato on the vine (TOV), cherry, grape, Roma and specialty. Within each tomato type are at least two dominant varieties, resulting in 21+ commercial varieties of tomatoes across all fruit types. This number is likely higher due to the wider variety in small tomato types (i.e.,grape and cherry), exclusive varieties and others being trialled. Each variety has a unique profile with respect to growth habit, time to harvest and fruit size, colour and flavour. As Sollum® experienced in commercial pepper production, varieties have unique responses to supplemental lighting and benefit from having tailored, dynamic lighting strategies.
A 20-week study conducted at Wageningen University compared the response of two tomato varieties to different percentages of red photons in the overall light spectrum. This study showed that the crop response was indeed cultivar-specific, with an increasing percentage of red light resulting in a lower fruit fresh and dry mass for Merlice but no significant difference for Brioso. The authors, who used a dynamic lighting system for the study, note that greenhouse growers need to consider the potential trade-offs between fixture efficacy and crop yield. With dynamic lighting, growers can adjust the percentage of red light according to the variety’s needs at any point in time.This allows growers to make the most of each cultivar throughout the season and adapt to new cultivars from season to season.
By implementing fully dynamic LED top lighting, growers gain the convenience of working with a single lighting system to create infinite light zones with variety-specific photoperiod, intensity and spectra dimmable in realtime. As result, the grower can take full advantage of each variety’s genetic potential.