Cocoa (Theobroma cacao L.) is one of the most important crops in Ecuador; however, its production is limited, among other factors, by the crop nutrition. The objective of this research was to determine the effect of the combined nitrogen, phosphorus and potassium fertilization on soil characteristics, growth traits and quality of shoots and fruits in cocoa. The experiment was carried out under a completely randomized design with factorial arrangement, with three factors, N, P and K, and two levels by factor (with and without fertilization), plus an absolute control without fertilization. The chemical characteristics of the soil, including pH, N, P, K, Ca and Mg content were evaluated. New shoots were also evaluated by measuring its number, length, leaf area, and growth rate. In the fruits, the weight, length and growth rate were measured. In shoots and fruits, quality traits including dry matter, fiber, ash, lipids and protein content were measured. Significant interactions of the applied nutrients were found, which increased the content of P and K, and decreased Ca and Mg of the soil. The N fertilization alone did not affect the growth of the shoots and foliar area. The interactions of the primary elements significantly increased the dry matter and fiber of the shoots, while the growth and quality of fruits were not modified.

Cocoa is a crop in increasing demand and cultivated worldwide. However, basic information concerning the movement of nutrients in leaves over time is still unknown, and methods to find an optimal time to collect a sample are still ambigu-ous. The present work focused on describing the movement of foliar nutrients (N, P, K, Ca and Mg) in productive 5-year-old cocoa clone CCN51 plants at the same dose of 114.8 kg ha-1 under different sources of nitrogen fertilization (Urea, calcium ni-trate, ammonium sulfate and a control without application). Samples were taken from the time the leaf reached 70% of its total expansion until 10 months of age. The results indicated that the contents of N, Ca and Mg increased as the leaf grew, remained stable between 116 and 158 days of shoot emergence (DSE) and then decreased at the beginning of the leaf senescence period. While the K and P con-tents decrease from the beginning of the trial until 158 DSE where they are stable until the final stage of leaf life. Around 110 to 120 DSE, the leaves of cocoa CCN51 show a more stable nutritional content, a period in which samples can be collected for leaf analysis.

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.

This chapter presents recent findings about the response of cacao crop to resources, both nutrients and solar radiation, under Amazonian conditions. Here, we review the results of our studies generated at field trials, and we discuss the crop response to different sources of nitrogen fertilization, as well as the response of cacao to Nitrogen-Phosphorus-Potassium (NPK) interaction. Ammonium sulfate significantly increased yield and fat seed in cacao compared to calcium nitrate and urea. Moreover, leaf nutrient movement during the productive season is described, finding substantial differences among elements and their leaf stages. We also discuss the effect of decreased solar radiation on growth and physiological traits. Mesh was used to reduce solar radiation. Shaded plants significantly reduced stomatal conductance; however, no significant effects on growth and foliar nutritional content were found, but there was an evident genotype effect. Although ammonium sulfate acidifies the soil compared to other N sources, its application improves yield, suggesting crop adaptation to acid soils, typically those of the Amazon region, and ammonium affinity. On the other hand, shade in the Amazon region conditions can alter physiological traits but does not affect plant growth, suggesting acclimatization to radiation modification. <!----> <!----> <!----> <!---->

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.