Spectral Reflectance Indices and Physiological Parameters in Quinoa under Contrasting Irrigation Regimes

Abstract

High temperatures, coupled with arid environments, are a major constraint to quinoa (Chenopodium quinoa Willd.) production. Here, we tested the effectiveness of multiple phenotypic and physiological parameters useful in the selection of heat‐tolerant quinoa genotypes. Initially, we screened 112 quinoa genotypes for leaf greenness index under high‐temperature greenhouse conditions. Of these, eight genotypes were selected for field evaluations under irrigated and rainfed treatments in two locations over two growing seasons (2016–2017) in Washington State. Of these eight, four genotypes were selected as potentially heat tolerant (QQ74, Baer, BGQ 352, and Pison), and four were selected as heat‐susceptible (17 GR, La Molina, 3 UISE, and Japanese Strain). Spectral reflectance indices including normalized difference vegetation index (NDVI) and green NDVI, as well as multiple physiological parameters, such as stomatal conductance, leaf temperature, and area under soil plant analysis development (SPAD) value decline curve (AUSDC), were evaluated. Results show variability in stomatal conductance among genotypes with 17 GR and BGQ 352 having the highest stomatal conductance and QQ74 the lowest. Baer, Pison, and QQ74 had the highest NDVI value across environments, and Japanese Strain had the lowest. Best linear unbiased prediction values in AUSDC showed that QQ74 had the highest leaf greenness and Japanese Strain had the lowest; these were classified as heat tolerant and heat susceptible, respectively. The NDVI is a potentially useful measure to predict grain yield in quinoa.

Leaf Gas Exchange Performance of Ten Quinoa Genotypes under a Simulated Heat Wave

“…Experiments were conducted in a greenhouse and growth chambers at the Nevada Agricultural Experimental Station in the University of Nevada, Reno. Ten quinoa genotypes contrasting in leaf greenness index and seed biomass response to high temperatures were provided by Washington State University (Table 1) [26]. Plants were grown in 34.3 cm tall and 10.2 cm wide pots (2.65 L; ID# CP413CH; Stuewe & Sons, OR, USA) with a 1:1 mix of sand (Commercial Grade Quikrete 30 grit) and soil medium (Sungro Fafard ® 3B Mix, Metro-Mix ® 830).…”

“…The present study aimed to understand the effects of high temperature on leaf gas exchange when quinoa plants were exposed to a four-day heat wave without drought as a confounding effect. We measured 10 quinoa genotypes, selected from a previous screening of 112 lines evaluated under high temperature conditions [26] for several parameters, including photosynthetic rate, stomatal conductance, intrinsic water use efficiency (WUE i ), chlorophyll fluorescence, membrane stability, aboveground biomass (shoots and seeds), and seed biomass.…”

Prospects for the accelerated improvement of the resilient crop quinoa

“…Na + can also be compartmentalized in mesophyll vacuoles in old leaves and, when such leaves are shed, Na + is also lost ( Adolf et al , 2013 ; Bonales-Alatorre et al , 2013 ). The stomatal length was reduced in 114 quinoa accessions subjected to salt stress ( Kiani-Pouya et al , 2019 ), suggesting that the design of the stomatal apparatus may also contribute to the water stress tolerance of quinoa ( Hinojosa et al , 2019a ; Kiani-Pouya et al , 2019 ).…”

Corrigendum: Seed Composition and Amino Acid Profiles for Quinoa Grown in Washington State

“…Table 1 ∣ Site characteristics for each year and location that samples were randomly selected from for chemical analysis. Raw quinoa seed sent for analysis was grown in 2016 and 2017 in western Washington as part of two separate experimental designs ( 13 , 49 ) .…”

“…** Raw quinoa seed sent for analysis was grown in 2016 and 2017 in western Washington as part of two separate experimental designs ( 13 , 49 ). Site characteristics for all locations are summarized in Table 1.…”