Spectral-reflectance indices of pigments in leaves of Andean crops

Reynoso W.M.S.; Palomino A.V.; Flores R.S.; Huaripaucar N.T.; Prado J.Z.D. · Acta Agronomica (2023) · DOI: 10.15446/acag.v72n1.106493

Resumen

In this study, spectral reflectance indices of pigments (chlorophyll, anthocyanin, and carotenoids) contained in leaves of six varieties of Andean crops registered in the National Institute of Agrarian Innovation (INIA) of Ayacucho, Peru, were studied: white grain maize (MB) INIA 620, Wari and purple corn and cob INIA 615 Black Canaan (MM) (Zea mays), white potato tubers (PB) of the Yungay variety and red potato tubers (PR) INIA 316 Ayacuchana Red (Solanum tuberosum), and white grain quinoa (QB) of the Blanca de Junín variety and red grain (QR) INIA 620 Pasankalla (Chenopodium quinoa). These indices were determined from spectral reflectance data R(λ) between 350 and 2500 nm, obtained using the ASD FieldSpec 4 spectroradiometer between February 17th and March 9th, 2020, the time span was divided into three well-defined periods (initial, critical, and final). Direct measurements of reflectance R(λ) in the visible region showed a greater presence of anthocyanins in QR red quinoa than in the other crops. The four calculated chlorophyll indices (SR, NDCI, ChlRE, Chlgreen) had the same downward behavior for each crop studied, and any of them can be used to quantify the chlorophyll content. Red quinoa, unlike the others, showed an increasing trend in the last measurement. For the anthocyanin and carotenoid indices, they showed the same behavior in each crop, that is, a tendency to decrease or stabilize as in QB, QR and PR. In the case of the ratio index of carotenoids/chlorophyll (Car/Chl), the same trend did not occur in each crop, however, the CClHE index is the one that best accommodated to the six crops, as it showed more stationarity for all of them. Nevertheless, it is advisable to validate its use for each crop.

Instituciones: Universidad Nacional de San Cristóbal de Huamanga