Estimation of leaf chrorophyll content of butterfly pea (Clitoria ternatea) as a function of fertilization utilizing a non-destructive, hand-held spectral analyser

Having grown up around horticulturists – my grandfather Dr. Carl Campbell was a Professor Emeritus of Horticulture (tropical fruit crops) for the University of Florida (UF) – a strong passion for researching and consuming horticultural crops has always been inherent. A three-time UF gator, I received both my bachelor’s and master’s degrees from UF, studying food science with a focus on the sensory sciences. Currently I’m pursuing my PhD at the UF Mid-Florida Research and Education Center (MREC) researching medicinal and beverage crop production in the state of Florida, with an emphasis on butterfly pea (Clitoria ternatea). Florida is normally associated with large scale citrus production, but the industry has been devastated by disease. The USDA reports that for 2016-2017 the state had a decline of 16, 28, and 17% in the previous season in orange, grapefruit, and total citrus production, respectively, due to the incursion of Huanglongbing (HLB) disease. Affected growers and producers are actively seeking replacement crops. Growers want crops with multiple economic values, one of which is an elevated concentration of important secondary metabolites that can be extracted, as is the case for the anthocyanin content of butterfly pea. An important forage legume in SE Asia, use of the fresh or dried flowers has become increasingly popular due to anthocyanin’s unique ability to convert from deep blue to light purple instantaneously when exposed to a mild acid such as lemon or lime juice. As a function of our extension appointment, research is currently being conducted to assist growers as they transition to these new crops, primarily through development of improved cultivation practices. In one example, our results instruct growers how to use a Konica Minolta SPAD-502Plus hand-held meter to non-destructively estimate leaf chlorophyll concentrations. Using a known SPAD index-value, producers can determine the relative leaf chlorophyll content of their plants with 99.89% accuracy. This can then be correlated to overall plant growth and function. By developing techniques like these, we’re able to directly assist growers and producers in our area, saving them valuable time and resources while diversifying the horticultural portfolio of the state of Florida.

Sean Campbell won an ISHS Young Minds Award for the best oral presentation at the II International Symposium on Beverage Crops in China in October 2018.

Sean Campbell, Medicinal and Beverage Crop Production, Environmental Horticulture Department, UF/IFAS Mid-Florida Research and Education Center, 2725 S Binion Rd, Apopka, FL 32703, USA, e-mail: scampbell53@ufl.edu

The article is available in Chronica Horticulturae