Waterlogging is an increasing constraint to crop productivity under climate change, yet information on quinoa’s sensitivity to excess water remains limited. This study aimed to identify the most vulnerable phenological stage of quinoa to waterlogging stress. A greenhouse experiment was conducted using the variety Tunkahuan, applying waterlogging (12 days) at six growth stages according to the BBCH scale, plus a well-drained control. Growth, chlorophyll content, biomass, yield components, and harvest index were assessed. Waterlogging significantly reduced growth and yield at all stages (p ≤ 0.05). Early vegetative stress reduced canopy cover and chlorophyll, with partial recovery after stress removal, but caused 73% plant mortality at BBCH 25. Reproductive stress, especially at anthesis (BBCH 60–67), was most critical, reducing yield by 71–77% compared to the control due to severe declines in grain number and harvest index. Stress during grain filling caused moderate yield reductions (22–28 g plant⁻¹). We conclude that quinoa is sensitive to waterlogging throughout its development, but anthesis is the most vulnerable stage for irreversible yield loss. These findings highlight the need for breeding programs targeting waterlogging tolerance and improved management practices to minimize flooding risk during flowering.

The cherimoya is a plant resource of high genetic and economic value. However, in Ecuador, it remains poorly documented, particularly under the restrictive orographic and climatic conditions of the Andean region. The lack of information limits the use of native materials in breeding and conservation programs. Therefore, this study evaluated native cherimoya populations using standardized fruit quality descriptors to quantify existing variability and identify promising native morphotypes. Hierarchical clustering was used to identify groups with similar traits. PCA captured the characteristics of the fruits that contribute to variability, while the multi-character index determined the traits that contribute to fruit quality. Remarkable diversity in commercial attributes, including pulp yield, fruit weight, and sweetness–acidity balance, was identified. Clusters highlighted the morphotypes LMPB04, SUMB04, and PTA01, from Loja, Saraguro, and Paltas, respectively, as having the highest titratable acidity and fruit weight. In contrast, the multi-character index prioritized the pulp/seed and SS/TA ratio, identifying potential in EACAD01 and LYHA01 from Espíndola and Loja, respectively. These results demonstrated the existence of superior cherimoya individuals adapted to Andean conditions and provide a basis for developing high-quality, promising material that meets local and international market demands.

Cherimoya is a fruit tree native to the Andean regions of South America, also in Central America, prized for its flavor, nutritional properties, and medicinal potential. Despite its economic relevance, in situ assessments of phenotypic diversity are limited, particularly in southern Ecuador, a key center of domestication. This study evaluated the morphological and ecogeographic diversity of 270 native trees across eight cantons in Loja province, Ecuador, using 34 qualitative and quantitative descriptors of leaves, flowers, fruits, and seeds. High phenotypic variability was observed, with coefficients of variation exceeding 40% for key traits, including mature fruit weight (48.15%), pulp weight (55.33%) and pulp-to-seed ratio (64.23%). Principal component analysis revealed three major axes of variation associated with productivity, floral morphology, and organoleptic quality. Cluster analysis identified four groups, with one distinguished by a favorable pulp-to-seed ratio and sugar–acid content. Species distribution modeling, which included bioclimatic and soil variables, showed that Gonzanamá, Quilanga and Espíndola possess the highest ecological suitability for cherimoya. These findings highlight priority areas for in situ conservation and phenotype selection, providing a foundation for sustainable use, genetic improvement, and the preservation of locally adapted germplasm to support climate-resilient agricultural systems.

Quinoa is a highly nutritious Andean crop with considerable yield potential that remains underexploited in southern Ecuador. This study evaluated the effects of planting method (row seeding, hill seeding, and transplanting) and plant density (8–20 plants m⁻²) on quinoa growth and yield under Andean highland conditions. A factorial field experiment was conducted using a randomized complete block design with three replicates. Plant density significantly affected grain yield, increasing from 4.4 to 4.8 t ha⁻¹ at 8 plants m⁻² to a maximum of 6.97 t ha⁻¹ at 20 plants m⁻². This increase was mainly driven by a higher grain number per unit area, while thousand-grain weight remained stable across treatments. In contrast, the planting method and its interaction with plant density had no significant effect on yield or yield components. Grain yield showed a strong positive relationship with above-ground biomass, indicating that biomass accumulation was the main driver of yield variation. These results demonstrate that plant density is the primary agronomic factor controlling quinoa productivity under Andean conditions. Optimizing plant density to 15–20 plants m⁻² is recommended as a simple and cost-effective management strategy to maximize grain yield, regardless of planting method.