Bramardi, S. J. | Search bioRxiv

bioRxiv2025

Harnessing drought tolerance in a reference set of Andean amaranths

Climate change and low-input farming systems increasingly expose crops to drought stress. Andean amaranths (Amaranthus spp.), as neglected and underutilized species, offer potential for climate-resilient agriculture due to their inherent drought tolerance and adaptability. In Northwest Argentina (NWA), a region with high environmental heterogeneity, exploiting this genetic diversity may improve food security. This study evaluated drought tolerance and yield stability among Andean amaranth genotypes to: assess the effects of genotype and GxE interaction, determine the potential for selecting specifically adapted genotypes, and identify high-yielding, stable genotypes for drought-prone conditions. Eleven genotypes (cultivars, breeding lines, and landraces of A. caudatus and A. mantegazzianus) were tested across four agroecological zones in NWA under irrigated and drought-stressed conditions. Grain yield data were analyzed using linear mixed models and AMMI analysis. Genotypes differed significantly in grain yield across environments and irrigation regimes. Strong GxE interactions led to genotype re-ranking across sites. Several A. caudatus breeding lines (G1, G2, G3, G6) combined high yield and stability. The A. mantegazzianus landrace (G11) was highly stable but low yielding. Amaranth genotypes showed distinct responses to drought, with some lines exhibiting broad adaptation and others, specific adaptation to stress-prone environments.

plant biology↗

bioRxiv2024

LEAF SHAPE OF QUINOA WILD ANCESTOR CHENOPODIUM HIRCINUM IN A GEOGRAPHIC CONTEXT

PremiseIntraspecific variation in plant traits, such as leaf morphology, offers insights into local adaptation and the ecological niche breadth of species. Chenopodium hircinum, the wild ancestor of quinoa, is widely distributed across various ecoregions in Argentina. A detailed comparative analysis of leaf morphology across 23 populations covering its entire distribution was conducted to understand patterns of intraspecific variation along geographic gradients. Materials and MethodsUsing 104 leaves from these populations, leaf shapes were described through shape, landmarks, and Fourier descriptors. Both univariate and multivariate analyses were employed to evaluate variations among and within populations and to link leaf shape patterns with climatic and geographical variables at the sites of origin. ResultsA significant variability in leaf shapes was found across all ecoregions, with marked integration among populations. While landmark-based and Fourier analyses differentiated populations, shape descriptors introduced complexity in identification. Leaf morphology varied widely, from rounded and toothed to sharply lobed, with prominent lobes located at the base or middle of the leaf. The key environmental factors influencing leaf shape, particularly lobulation and relative positioning, were mean annual temperature and altitude. ConclusionsThe findings suggest that in C. hircinum, leaf shape variability goes beyond the simple lobed vs. entire dichotomy and is shaped by environmental temperatures. Leaf morphology and margin traits are primarily governed by the relative position of the lobes, which are strongly correlated with the mean temperature at the populations origin. This convergence across different ecoregions highlights the need for further research to explore the functional significance of such variation.

plant biology↗