Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

During postharvest storage oca tubers can pass for different stages, in which bioactive compounds can change their content; and specifically the sprouting stage, can alter significatively these components. Therefore, this study evaluated the sprout length, loss weight, reducing sugar content, total phenolics content, and antioxidant capacity of three oca tuber varieties (yellow, purple, and orange) during postharvest storage. Oca tuber varieties were stored at 19 °C ±1 ºC and relative humidity of 85% ±1%. A factorial design was used to evaluate the effect of oca variety and postharvest storage time (0, 15, 30, 45, 60, 75, and 90 days). The sprout length of the three oca varieties begin to growth at 15-30 days of postharvest storage, which indicated that dormancy period was broken, moreover, the sprout length was increased until 90 days of storage. Yellow oca had the longest sprout length (26.4 cm) and the highest loss weight (22.55 %) at 90 days of storage, which indicated an effect of oca variety and postharvest storage time (p value≤0.05). The reducing sugar content, total phenolics content, and antioxidant capacity of the three oca varieties exhibited variable behaviors during storage time and initially oca tubers showed a reduction in their values, which were presumably related to the stabilization period. The postharvest storage time and oca variety produced different physiological changes in the oca tubers, which affect the sprout length, weight loss, reducing sugars, total phenolics content, and antioxidant capacity.

This study analyzed the rhizosphere bacterial communities in sugarcane fields subjected to different durations of agronomic management: recent (5 years) and long-term (over 50 years). The objective was to evaluate the diversity of rhizosphere bacteria using 16S rRNA gene sequencing and assess their correlation with soil management practices. Results showed distinct bacterial compositions between recently and long-term managed fields. Significant associations were observed between bacterial species and soil conditions characterized by high electrical conductivity (EC), elevated concentrations of Ca²⁺, K⁺, Fe²⁺/Fe³⁺, and Mg²⁺, and low CO₃²⁻ levels. Dominant species included Bacillus megaterium, Bacillus subtilis, and Bacillus simplex, representing the phyla Actinobacteria, Proteobacteria, and Firmicutes, respectively. An analysis of the outlying mean index explained 76.2 % of the total variation, highlighting key soil factors. The first axis (44.7 %) correlated with EC and organic matter content (OM), while the second axis (31.5 %) was associated with extractable phosphorus (P) and potassium (K) levels. These findings underscore the influence of soil physicochemical properties-such as EC, OM, and nutrient availability-on rhizosphere bacterial diversity and composition. These variables modify the soil microenvironment, favoring certain bacterial groups over others and directly impacting soil fertility and agricultural productivity. This study provides insights into the interaction between rhizosphere bacteria and soil management practices. Understanding microbial dynamics in long-term managed systems paves the way for strategies that improve soil health and crop productivity in intensive agricultural systems.

Common bean (Phaseolus vulgaris L.) is one of the most widely cultivated legumes worldwide due to its high nutritional value and role in food security. In Peru, its production in the Chincha Valley is vital for small and medium-scale farmers, serving as a key source of income. However, its productivity depends on agroclimatic and genetic factors. This study evaluated the performance of nine bean lines in the Chincha Valley to identify materials with greater productive potential. A Randomized Complete Block Design (RCBD) was used, assessing 14 traits through statistical analyses such as ANOVA, Pearson correlation coefficient, Principal Component Analysis (PCA), and hierarchical clustering. The PCA explained 40 % of the total variability in the first two dimensions. The first (23.3 %) was associated with yield components, while the second (16.7 %) was related to phenology, 100-seed weight, and pod length. The 100-seed weight showed a positive correlation with pod length (r=0.80) and a negative correlation with days to harvest maturity (r =-0.56). Can D8120 and Arbolito (cluster A) were the most productive lines (1402.75 and 1511.00 kg·ha⁻¹), with an intermediate 100-seed weight (49.30-51.70 g). Larán Mejorado (cluster B) stood out for its larger seed size and intermediate yield. These findings are keys for selecting high-yielding lines and incorporating them into breeding programs.

Tithonia diversifolia is a shrub species that has gained increasing importance as an alternative species for forage due to its nutritional profile. Its agronomic and nutritional characteristics can vary depending on the environment. Therefore, the objective of this study was to evaluate the agronomic, morphological and nutritional characteristics of Tithonia diversifolia in two altitudinal zones of the Amazonas region, Peru. Plants were cultivated in Chachapoyas (2445 m.a.s.l.) and Cajaruro (797 m.a.s.l.), two locations with contrasting soil, climate, and altitude conditions. The bud burst, agronomic, morphological and nutritional characteristics of T. diversifolia were evaluated. The bud burst, dry weight, dry matter content, plant height, growth rate, carbohydrate content, and gross energy were significantly higher (p<0.05) in T. diversifolia cultivated in Cajaruro. In contrast, crude protein and mineral content were higher (p<0.05) in Chachapoyas. No significant differences (p>0.05) were found for fresh weight, number of leaves/plant, number of shoots/plant, ether extract, and crude fiber. These results suggest that T. diversifolia expresses favorable characteristics for forage in a high-altitude environment, and shows high phenotypic plasticity, which is important for its adaptation and cultivation across diverse agroecological zones.

Uvina is one of the eight grape varieties permitted for the production of pisco in Peru and is part of the country's cultural heritage. However, the effect of rootstocks on its properties has not been widely studied. The influence of different rootstocks on the morpho-productive characteristics of Uvina from the INIA Germplasm Bank was evaluated, considering fourteen qualitative traits. Descriptive analyses were performed, as well as ANOVA with comparison of means using the Tukey test (P < 0.05). For nonparametric tests, the Kruskal-Wallis test with Holm post hoc test (P < 0.05), in addition to Pearson correlation and principal components analyses. The results showed that the Salt Creek and 5BB rootstocks stood out for presenting the highest number and mass of bunches per plant, as well as greater internode length and shoot mass. Paulsen showed intermediate performance, while MGT recorded the lowest values in most of the variables analyzed, with the exception of total soluble solids content, a parameter in which it outperformed the others. It is concluded that the rootstocks significantly influenced the morphological and productive characteristics of the Uvina.

The widespread use of neonicotinoid insecticides in crop management can generate residues with negative impacts on consumer health. The objective was to determine residues and the dissipation of imidacloprid in grape berries and soil following applications of the insecticide imidacloprid at four doses and in two forms in an arid area. The research was conducted on a ´Red Globe´ grape plantation located in Arequipa, Peru. The treatments consisted of applying four doses of a commercial formulation of the insecticide imidacloprid (0.5, 1.0, 1.5, and 2.0 L·ha-1) using two application forms (foliar spray and plant collar drench). Eight treatments were evaluated in a DBCA design, with three replicates per treatment and 24 experimental units. The commercial insecticide used was Diprid 350EC, applied 35 days before the harvest of the bunches. Imidacloprid was determined by HPLC in berries and soil obtained 1, 7, 14, 21, 28, and 35 days after the initial application of the insecticide. In grape berries, the treatments indicated did not generate imidacloprid values above the MRLs. Foliar application resulted in higher imidacloprid residues than drenching, regardless of the dose administered. The ingestion of grape berries with imidacloprid residues in the treatments indicated does not pose any health risk. In the soil, none of the treatments exceeded the investigated sanitary level of imidacloprid; therefore, accidental contact with these soils will not pose any health risk to humans.

The bacterium Azospirillum brasilense has been studied for being associated with the stimulation of plant growth by production of auxins, especially indole acetic acid, in addition to the biological fixation of nitrogen. Genome analysis is used to generate a genome fingerprint matrix and with them build a tree to distinguish the differences between species of this genus. To carry out this analysis, it was carried out with the virtual genomic fingerprinting method using the VAMPhyRE program. Probes were designed to detect 19 nucleotides and with the results obtained, a genomic fingerprint matrix was generated from which a genomic tree of minimal evolution was built, which revealed the phylogenomic relationships between the species of the genus, highlighting that the Brazilian species A is separated in a clade perfectly differentiated from the other species of the group. Likewise, the analysis allowed us to detect that the A brasilense genome is composed of 19,284 genes, which is equivalent to 16 % of the genes annotated and make up the core genome of the strains analyzed. Likewise, 27 % are moderately conserved genes. This is evidence of the great genomic variability that the species presents. In addition, a graph of the genome of the species was generated. Also, using the PROKKA program and the virtual genomic fingerprinting method, a matrix of distances and a phylogenomic tree of minimal evolution were generated, without roots, in radial shape showing that all A. brasilense strains are housed in the same clade and separated from the other species of this genus.

Crown rot is the most important postharvest disease in banana worldwide. The post-harvest antifungal activity of potassium silicate (SP) against crown rot (CR) of banana inoculated with Colletotrichum musae (Cm) was determined. Treatments with SP (from 30 to 160 mM) were tested through in vitro and in vivo (from 70 to 300 mM) experiments. The 90 mM concentration of SP in in vivo experiments was selected as the most effective and used in experiments on the influence of dip temperature on PS effectiveness. Curative dip treatments of 90 mM SP at 40 °C for 20 min applied alone or in combination with low doses of thiabendazole (TBZ) were evaluated on CR, as well as the effect of SP on banana quality. SP at 90 mM totally inhibited the mycelial growth of Cm as well as significantly reduced the severity of CR in both preventive (51.1 %) and curative (59,5%) treatments in in vivo primary experiments. Among the dips with PS at 90 mM for 20 min tested at different temperatures, the dip at 40 °C was selected as the most effective. The combined curative dip treatment, SP+TBZ, improved the control against CR with an incidence reduction of 91.6 %. SP does not affect banana fruit quality.

Endophytic fungi are organisms that can promote growth and resistance to abiotic stresses in plants. The objective of this study was to evaluate the effect of various endophytic fungi on the vegetative growth of the 'Salt Creek' vine rootstock at nursery conditions. Fourteen fungal strains plus a non-inoculated control were evaluated to constitute a trial with 15 treatments and 4 repetitions under a completely randomized design. The strains with concentration of 1×106 ufc·g-1 were inoculated every 15 days on the plants, and measurements of growth were made after 105 days. The results indicated that the Aspergillus niger strain outperformed the vast majority of strains, except for Trichoderma inhamatum and Cladosporium halotolerans, with which it shared statistical significance in the variables of shoot length and diameter, root length, and aerial biomass, and with T. asperellum and Penicillium steckii in the variable of total biomass. In the root biomass, the highest averages were found in two strains of T. asperellum. It is concluded that the strains of A. niger, T. inhamatum and C. halotolerans are the ones that best promote the vegetative growth of the vine rootstock in its initial stages, while demonstrating very good potential for its application in crops for sustainable agriculture.

Cocoa seeds are recalcitrant, resulting in a faster loss of viability with storage time and the tetrazolium test is an alternative to determine the viability of these seeds as quickly as possible. The objective of this study was to develop a tetrazolium test protocol for cocoa seeds to assess seed viability. Seeds were extracted from fruits and after the processing were subjected to the tetrazolium test considering 7 times in tetrazolium solution (2, 3, 4, 5, 6, 7 and 8 hours) and 2 concentrations of tetrazolium solution (0.05 % and 0.075 %). Before this, seeds were soaking for 6 hours in germination paper and the seed coats were removed. During the immersion on tetrazolium solution, seed were maintained in a germination chamber at 42 °C. After this, seeds were categorized into 4 classes, according to the coloration of embryonic axis, with the living tissues being dyed with light pink color while dead tissues were non-colored. To confirm the results of tetrazolium test, a germination test was carried out to associate the percentage of germination with the percentage of viable seeds obtained by the tetrazolium test. Considering this, the recommended immersion time in the tetrazolium solution is 3 hours with a concentration of 0.05 %.