Effects of novel greenhouse covering materials on the physiology and quality of lettuce cultivars and their attractiveness to aphids

Abstract

The world population is projected to reach 10 billion by 2055, imposing the need for doubling food production to prevent a food crisis under unfavourable environmental conditions such as drought, costly energy and a scarcity of arable lands. As a result, there is a rising interest in the Protected Cropping industry in photoselective covering materials that increase production and reduce energy costs. LLEAF 620 (LFC) is a cover that emits light from 600 - 680nm with a peak at 620nm and is expected to improve vegetable production. Smart Glass - ULR-80 (SGC) is an architectural cover that blocks 85% of ultraviolet (UV) light, 19% of PAR, 58% far-red, and 26% red light; hence, it is expected to reduce the requirement for cooling energy by reflecting heat-generating wavelengths. Butter Head, Red Cos and Green Cos cultivars were used for the first two full-scale replicated experimental trials on the effects of LFC on lettuce in a high-tech hydroponic glasshouse, and the first on the effects of SGC on leafy vegetables. The study was performed in the 1800 m² multi-span gable-roof high-tech autonomous hydroponic glasshouse of the National Vegetable Protected Cropping Centre (NVPCC) that was established in 2017 at the Hawkesbury campus of Western Sydney University, located in Richmond, New South Wales. LFC exhibited a positive effect on yield, a negative one on pigmentation and Manganese (Mn) levels, and no effect on quality. SGC impacted Lettuce yield and pigmentation but did not affect quality or minerals. Additionally, SGC incited lettuce to release volatiles that were observed to be unfavourable by Green Peach Aphids in Olfactometer Bioassay trials on Red and Green Cos Lettuce. Subsequently, SGC can potentially assist in plant protection in greenhouses. Cultivar and seasonal-specific responses were observed in plants under both covers.

Date of Award	2022
Original language	English