The feijoa is a fruit tree recently grown in the highlands of Veracruz, Mexico. The objectives of this study were to determine some physicochemical and nutritional characteristics of feijoa fruits harvested in Veracruz and to show that some of these attributes are comparable to those of fruits from other producing areas. Commercial-sized fruits were obtained from eight-year-old trees with a single compost application per year. The total soluble solids, pH and acidity of the pulp, in fruits stored at 4, 12 and 25 °C, were similar to those reported in feijoas cultivated in temperate zones. The carbohydrate, fat, fiber, ash, moisture and protein contents in the pulp differ slightly from those reported in the literature. On the other hand, the concentration of vitamin C was higher in the shell than in the pulp. This is the first information on quality parameters of feijoa grown in Mexico. This crop was appropriately adapted to the environment of a high tropical zone.

Nephelium lappaceum L. is a highly perishable tropical fruit because of its susceptibility to pericarp dehydration and oxidation, which decreases its acceptance in the fresh produce market. The aim of this study was to evaluate the effect of agronomic practices such as pruning, girdling and water stress on some postharvest quality parameters in rambutan fruits from ‘RJA Clone’ trees in Chiapas, Mexico. A split-plot experimental design in randomized complete blocks with a factorial arrangement and six replicates was used. Fruits from trees managed under water stress conditions showed greater fresh weight (40.2 g), concentration of total soluble solids (TSS, 22.62 °Brix), total sugars (423 mg∙100 g^-1), vitamin C (37.79 mg∙100 g^-1) and titratable acidity (0.30 %). On the other hand, it was found that water stress caused a 33 % weight loss in fruits, in relation to fruits from irrigated trees (48 %). The latter were characterized by having less sweetness (between 18 and 19 °Brix) and higher acidity (0.417 %). In general, the application of temporal drought, girdling and pruning contributed to the obtaining of fruits with greater size, shelf life and sweetness, less weight loss and with a higher concentration of bioactive compounds (vitamin C and total phenols), in addition to acquiring physical and biochemical characteristics desirable for fresh consumption.

Aloe (Aloe barbadensis Miller) is a water deficit-tolerant plant. Products obtained from the leaf have a high commercial value in the medical, food and cosmetological industries. The aim of this study was to evaluate the growth and development of aloe (Aloe barbadensis M.) plants and the quality of its gel when applying bat guano extract (BGE) and seaweed extract (SE) in different soil moisture contents. A split-plot randomized block design was used with three replicates. The large plots were soil moisture contents: low (13 to 17 %), medium (18 to 22 %) and high (23 to 27 %); the medium plots were the BGE doses (0 and 20 L∙ha-1∙year-1), and the small plots the SE doses (0 and 20 L∙ha-1∙year-1). At 152, 238 and 458 days after the first application of the biofertilizers (DAFAB), plant height (cm), leaf length, width and thickness (cm), gel weight (g) and concentration of total soluble solids (TSS, %) in the gel were measured. Leaf width and thickness were higher when the soil moisture content was close to field capacity (23 to 27 %), while leaf length and width were higher in the first two evaluations when the moisture content was medium (18-22 %). The TSS concentration did not show significant statistical differences (P ≤ 0.05) in any treatment. At the end of the evaluation cycle (458 DAFAB), BGE increased leaf width and thickness.

Manual pollination used in breeding programs is costly because it requires a large amount of labor, so it is necessary to optimize the process. The aim of this study was to determine the optimal time to carry out manual pollination efficiently in tomatillo. Closed flower buds with yellow coloration were covered and five manual pollination times (days one, two, three, four and five) and one non-pollinated control were evaluated in two families of the Diamante and Manzano varieties. A 5 x 2 x 2 factorial treatment design was used in a randomized complete block experimental design with four replicates. The experimental unit consisted of 10 floral buds. The number of fruits (NF), fruit weight (FW), total seed weight (TSW), total number of seeds (TNS) and weight of 100 seeds (W100S) were evaluated. The highest efficiency was obtained when manual pollination was carried out on the second and third days. The Diamante variety had a higher NF (7.8), TSW (2.315 mg) and TNS (1.415.8), while Manzano Tepetlixpa had higher FW (420.17 g) and W100S (191,538 mg). Family one of the Diamante variety was superior in TNS, but family two had larger seed size. In Manzano Tepetlixpa there were no differences between families. On the other hand, Diamante reached its highest seed production with pollination on day three, without statistically exceeding day two. Manzano had higher seed production when pollinated on day two, but did not statistically exceed day three. Therefore, it was determined that the optimal period of pollination in tomatillo is between two and three days after having covered the floral buds.

The sugar content in the potato tuber determines the optimum harvest time, the type of processing and its handling during storage. The aim of this study was to evaluate the growth and yield of four potato varieties under greenhouse conditions and to determine the soluble sugar content of this tuber at different maturity stages. For this, potatoes (5 ± 1 g) of four varieties were sampled at four maturity stages, from the beginning of tuberization to physiological maturity, in which the soluble sugar content was determined by high-performance liquid chromatography (HPLC). The Alpha variety had the longest growth cycle (1,230 degree days, P ≤ 0.05), while Mondial had the highest yield (380 g, P ≤ 0.05), 75, 31 and 31 % more than Vivaldi, Alpha and Atlantic, respectively, attributed to the highest average tuber weight (61 g, P ≤ 0.05). The highest content of sucrose, glucose and fructose (7.65, 2.22 and 0.37 mg·g-1, respectively) was recorded 21 days after the start of tuberization, quantities that decreased (P ≤ 0.05) during tuber development. Atlantic stands out with the lowest levels (P ≤ 0.05) of sucrose, glucose, fructose and total sugars in the different stages of tuber maturity. Average tuber weight was negatively correlated (P ≤ 0.05) with the contents of sucrose, reducing sugars (glucose and fructose) and total sugars.

Stevia rebaudiana, known as sweetleaf, produces a sweetener in its leaves due to the presence of steviol glycosides (stevioside and rebaudioside); however, its seed has germination problems, which is why various temporary immersion systems (TIS) have been studied for its production. The objectives of this study were to scale up the in vitro production of two S. rebaudiana cultivars using RITA®, BIT® and SETIS®, and to evaluate the production of biomass in the field. The studied cultivars were ‘Morita II’ and ‘Silvestre’. The production stages of both cultivars were: in vitro, liquid medium (with three TIS: RITA®, BIT® and SETIS®), greenhouse and finally they were taken to the field. In each TIS, five different media were evaluated, varying in each one the concentrations of sucrose, calcium pantothenate and gibberellic acid. The treatments produced vigorous plants, a greater number of leaves and shoots, and a higher multiplication rate. Both cultivars had greater stem length in BIT. Under this same system ‘Morita II’ produced eight shoots per plant, while in SETIS only three. ‘Silvestre’ had two shoots per plant with the two TIS. In both cultivars, regardless of the TIS, greenhouse survival and foliage production in the field were very similar. Therefore, the selection of the material should be based on the content of steviosides and the adaptation of the cultivar to the planting site. All TIS evaluated allowed scaling-up plant production, and both materials are promising for planting.