Search

Background: Photoperiod is an important environmental cue interacting with circadian clock pathway to optimize the local adaption and yield of crops. Quinoa (Chenopodium quinoa) in family Amaranthaceae has been known as superfood due to the nutritious elements. As quinoa was originated from the low-latitude Andes, most of the quinoa accessions are short-day type. Short-day type quinoa usually displays altered growth and yield status when introduced into higher latitude regions. Thus, deciphering the photoperiodic regulation on circadian clock pathway will help breed adaptable and high yielding quinoa cultivars. Results: In this study, we conducted RNA-seq analysis of the diurnally collected leaves of quinoa plants treated by short-day (SD) and long-day conditions (LD), respectively. We identified 19,818 (44% of global genes) rhythmic genes in quinoa using HAYSTACK analysis. We identified the putative circadian clock architecture and investigated the photoperiodic regulatory effects on the expression phase and amplitude of global rhythmic genes, core clock components and transcription factors. The global rhythmic transcripts were involved in time-of-day specific biological processes. A higher percentage of rhythmic genes had advanced phases and strengthened amplitudes when switched from LD to SD. The transcription factors of CO-like, DBB, EIL, ERF, NAC, TALE and WRKY families were sensitive to the day length changes. We speculated that those transcription factors may function as key mediators for the circadian clock output in quinoa. Besides, we identified 15 novel time-of-day specific motifs that may be key cis elements for rhythm-keeping in quinoa. Conclusions: Collectively, this study lays a foundation for understanding the circadian clock pathway and provides useful molecular resources for adaptable elites breeding in quinoa. [ABSTRACT FROM AUTHOR]

Quinoa (Chenopodium quinoa Willd.) is an ancient food crop that originated in the Andes. It has good nutritional properties that increasingly attract interest around the world and it is considered as a future crop for food security and climate change adaptation. Currently, there is a great need to develop new quinoa varieties with higher yield, tolerance to biotic and abiotic stresses, and adaptation to new growing areas. Despite the existence of breeding programs, quantitative genetic parameters that are relevant for selection gain have hardly been investigated for quinoa. We estimated these parameters for important agronomic traits in six segregating populations of 96 lines each, derived from crosses of popular traditional Peruvian quinoa varieties. The traits were evaluated in trials at several locations in the Peruvian highlands over 3 years. Maturity was the best phenological stage for trait evaluation because at this stage we obtained high estimates of heritability and high correlation of panicle trait indices with grain yield. Based on these traits, we selected the 18 best lines and characterized them in additional field trials for the same traits. Three lines (HUA × KAN53, SAL × NCO46 and SAL × PAN171) combined advantageous traits of their parents and showed lower plant height, earlier maturity and higher yield. Our work shows that the estimation of variance and variance components in the amphidiploid crop quinoa provides useful information for the design of breeding programs and the selection of improved genotypes for cultivation in the Peruvian highlands. [ABSTRACT FROM AUTHOR]

Abstract: Night radiative frost is a highly limiting factor for agriculture in Andean highlands. Nevertheless, a diversity of crop species have been domesticated there, commonly showing high heterogeneity in plant growth at the field level. The possible protective effect of crop canopy heterogeneity against nocturnal radiative frost is examined using a dual approach, combining a field experiment and a simplified energy balance model at the leaf level. Leaf and air temperatures were registered over an entire quinoa crop cycle in the Andean highlands of Bolivia, comparing two cultivars: Blanca de Yanamuyu, a traditional landrace with high plant height heterogeneity, and Surumi, a more homogeneous selected variety. In both cultivars, inverted air density profiles during calm and clear nights result in air temperature changes up to 3°C over 0.5m height, with minimum air temperature concentrated at the upper part of the canopy. In these conditions, leaf temperature gradients of up to 2.6°Cm−1 develop within the canopy of the traditional landrace, with minimum leaf temperature significantly higher (P <0.001) in shaded plants of the landrace than in the selected cultivar. A dynamic model of leaf temperature based on canopy parameters and climatic records at screen level adequately simulates leaf temperature differences in the case of a vertically heterogeneous quinoa canopy. A sensitivity analysis of the model reveals that canopy height, leaf area index, and sky cloudiness have the most important influences on the development of the sheltering effect, while air temperature and air humidity play a minor role under typical radiative frost conditions. As for wind speed, its actual influence remains unclear due to experimental and modelling limitations at low wind speeds. The significance of these results is discussed in terms of the trade-off between stress adaptation and biomass productivity. [Copyright &y& Elsevier]