Effects of Light Level and Integral On Whole-Plant and Leaf Level Characteristics of Two Differently Adapted Quinoa Cultivars.

Effects of light level and integral on whole-plant and leaf level characteristics of two differently adapted quinoa cultivars

Quinoa (Chenopodium quinoa Willd.) is a highly nutritious Andean seed crop with high adaptability to adverse environmental conditions. Most of the existing cultivars are short day plants and sensitive to day length conditions but a few day length neutral cultivars are available and the potential for further adaptation outside the centre of origin is promising. However, limited work has been done on photoperiod and light integral influence on quinoa development of differently adapted cultivars. To further separate the effects of day length, light level and integral on whole-plant development, leaf characteristics and photosynthetic light responses of quinoa, a short-day cultivar (Achachino) and a day length neutral cultivar (Titicaca) were subjected to four photoperiod treatments. Short day (10 h) was applied with a level of photosynthetic photon flux density (PPFD) of 600 µmol m^-2 s^-1, resulting in a PPFD integral of 21.6 mol m^-2 day^-1. The long day treatments were given with 350 and 600 µmol m^-2 s^-1 giving a PPFD integral of 21.4 and 36.7 mol m^-2 day^-1. To be able to separate the effect of day length, level of PPFD and PPFD integral, a long day treatment was created with 10 h of 600 µmol m^-2 s^-1 PPFD, combined with 7.5 h day extension applied with dim light from an incandescent light bulb triggering the phytochrome system, resulting in a PPFD integral of 21.7 mol m^-2 day^-1. Preliminary results suggest great variation between the four different treatments in terms of carbon, nitrogen, and chlorophyll content as well as plant development dependent fluorescence and light curve responses. Differences between cultivars were also prevalent. Results will be discussed in further detail.