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

Butterfly pea (Clitoria ternatea), a fast-growing legume prized for its deep blue to purple flowers, is a popular food and beverage colorant in Southeast Asia. Recently, butterfly pea has become increasingly popular within the United States. Although literature examining relationships between fertility and plant performance are available, non-destructive chlorophyll estimation techniques have not been evaluated. To assist growers in butterfly pea production, 144 plants cultivated in a greenhouse in Apopka, Florida, United States, were treated with one of three different slow-release fertilizer applications and assessed for chlorophyll concentration using a Konica Minolta SPAD-502Plus hand-held meter. Differences in chlorophyll content were observed among treatments. Additionally, six plants were treated with one of four soluble fertilizer treatments and analysed for chlorophyll using both destructive (Thermo Scientific Evolution 201 UV/VIS Spectrophotometer) and non-destructive (SPAD) techniques. Regression analysis was performed between the destructive and non-destructive techniques, converting the SPAD index-value into a fertility reference. This information can be utilized by growers to assess fertility needs without need for destructive tissue analysis.