Effect of high temperature on pollen morphology, plant growth and seed yield in quinoa (Chenopodium quinoa Willd.)

Abstract

Quinoa (Chenopodium quinoa Willd.) has gained considerable attention worldwide during the past decade due to its nutritional and health benefits. However, its susceptibility to high temperatures has been reported as a serious obstacle to its global production. The objective of this study was to evaluate quinoa growth and pollen morphology in response to high temperatures. Pollen morphology and viability, plant growth and seed set, and several physiological parameters were measured at anthesis in two genotypes of quinoa subjected to day/night temperatures of 22/16°C as a control treatment and 40/24°C as the heat stress treatment. Our results showed that heat stress reduced the pollen viability between 30% and 70%. Although no visible morphological differences were observed on the surface of the pollen between the heat‐stressed and non‐heat‐stressed treatments, the pollen wall (intine and extine) thickness increased due to heat stress. High temperature did not affect seed yield, seed size and leaf greenness. On the other hand, high temperature improved the rate of photosynthesis. We found that quinoa has a high plasticity in response to high temperature, though pollen viability and pollen wall structure were affected by high temperatures in anthesis stage. This study is also the first report of quinoa pollen being trinucleate.

Heating quinoa shoots results in yield loss by inhibiting fruit production and delaying maturity

“…35–40 days old). Previous studies in both growth chambers and in the field showed that temperatures above 32°C impaired the yield and caused physiological and phenotypic changes in quinoa (Bazile et al , ; Hinojosa, Matanguihan, et al , ), and therefore the growth chamber temperature was set to 35°C. We found that the soil temperature was 30°C when the air temperature was 35°C, and therefore 30°C was selected as the heat treatment for roots.…”

“…There is growing interest in expanding quinoa cultivation (Jacobsen, ; Pulvento et al , ; Choukr‐Allah et al , ; Bazile et al , ; Maliro et al , ), because of its nutritious grain (Repo‐Carrasco et al , ; Vega‐Gálvez et al , ; Choukr‐Allah et al , ) and its ability to grow on poor soils (Jacobsen et al , ). Heat is a major limitation to expanding quinoa cultivation (Lesjak and Calderini, ; Hinojosa, Matanguihan, et al , ), however, and quinoa generally does poorly in climates with average temperatures higher than 32°C (Bazile et al , ; Hinojosa, Matanguihan, et al , ). A goal of this study is to gain a better understanding of how heat limits grain production in quinoa.…”

Impact of heat and drought stress on peroxisome proliferation in quinoa

“…In Pison, QQ74 and 17GR, stomatal conductance was not affected by heat stress. Opened stomata at high temperature (40/24°C day/night) in QQ74 and 17GR cool the leaves through transpiration (Hinojosa et al ., ). High temperature caused stomatal opening in quinoa cultivars ‘Titicaca’ and ‘Achachino’, and in other species such as Lens culinaris , Hordeum vulgare , Nicotiana tabacum and A. thaliana (Rizhsky et al ., , ; Yang et al ., ; Becker et al ., ; Cantalapiedra et al ., ; Sehgal et al ., ).…”

“…Although quinoa is adapted to marginal environments, its yield can be diminished by high temperature (Bhargava et al ., ; Pulvento et al ., ; Hirich et al ., ; Peterson and Murphy, ; Bazile et al ., ; Eisa et al ., ; Lesjak and Calderini, ; Hinojosa et al ., ) or drought (Walters et al ., ; Al‐Naggar et al ., ). However, warm temperatures (28/20°C) were shown to increase plant height, photosynthesis rate, stomatal size and seed yield in quinoa (Yang et al ., ; Becker et al ., ).…”

“…Quinoa adapts to drought conditions (Geerts et al ., ; Martínez et al ., ; Razzaghi et al ., ; Walters et al ., ; Maliro et al ., ) by accumulating solutes, reducing leaf stomatal conductance and modulating root architecture (Bosque Sanchez et al ., ; Jacobsen et al ., ; González et al ., ; Alvarez‐Flores et al ., ). High temperatures stimulate quinoa growth (Yang et al ., ; Becker et al ., ; Bunce, ; Hinojosa et al ., ) but diminish seed yield, particularly under drought conditions (Fuentes and Bhargava, ; Peterson and Murphy, ; Walters et al ., ; Lesjak and Calderini, ; Hinojosa et al ., ). However, the reasons for the high sensitivity of quinoa to the combination of heat and drought remain poorly understood.…”