The Gema population of the husk tomato (Physalis ixocarpa Brot. ex Horm.) is the result of selection towards very large fruit from F1 of the intervarietal crossing of Verde Puebla and CHF1-Chapingo. After six selection cycles, genetic variance and heritability are likely to have decreased, which could make genetic improvement difficult. The aim of this study was to determine (through heritability [ĥ2], the coefficient of additive genetic variation [CVA] and the additive genetic correlation) whether it is possible to continue with the genetic improvement of the Gema population. Four quantitative traits were studied in 200 families, obtained from the Gema population, under a randomized complete block experimental design with three replications and 22 plants per experimental unit. The CVA ranged from 18.08 to 29.32 %, and the ĥ2 fluctuated between 32.03 and 44.14 %. The highest ĥ2 was found in yield per plant, whose 1-α confidence interval for ĥ2 was estimated to be between 29.2 and 56.3 % (α = 0.05). High, positive and significant additive genetic correlations were found between number of fruits per plant and yield per plant. Therefore, it is possible to obtain significant advances by selection in the Gema variety. The greatest gain could be obtained for yield per plant and number of fruits, with emphasis on the first trait.

One of the advantages of controlled agriculture is the notable increase in crop yields. However, at high-tech levels, water use productivity has increased, while energy use productivity has decreased. Therefore, the objective of this study was to estimate water, energy and labor use productivity in tomato cultivation, for a low-tech greenhouse. The inputs used in the production process were recorded from April 24 (date of transplant) to October 16, 2016 (date of last harvest). The yields obtained were 19.07 kg∙m-2. Water use productivity was 27.86 kg∙m-3 (35.89 L∙kg-1), which is within the range reported for unheated plastic greenhouses (30-40 L∙kg-1). Energy productivity was 0.331 kg∙MJ-1, and the energy consumed per unit area was 57.61 MJ∙m-2, with Calcium nitrate being the input with the highest energy demand (49.49 %). During the production cycle, 738 working hours were used, 78 % of which were dedicated to cleaning and maintenance, with labor productivity of 3.02 kg∙h-1.

The main collection of allelic variants for breeding tomato (Solanum Lycopersicum L.) is represented by its wild relatives, which evolved independently. It is important to study different sources of variation that are useful in breeding; therefore, the aim of this study was to evaluate S. habrochaites Knapp & Spooner as a source of different alleles by estimating the average degree of dominance, heterosis with respect to the mid-parent, and narrow-sense heritability of an interspecific cross with S. lycopersicum L. An S₈ line derived from the LOR95 collection, the LA1223 accession of S. habrochaites Knapp & Spooner and the F₁ generation from crossing the two materials were used. Genotypes were evaluated in a randomized complete block design during two greenhouse cycles in a hydroponic production system. Of 14 evaluated traits, total soluble solids concentration, stem diameter, total number of fruits and plant height showed an overdominance of LA1223, as well as heterosis of 17.2, 32.3, 55 and 49.2 % each, and heritability of 35, 93, 72 and 66 %, respectively. F₁ generation had an increase of 2 mm in stem diameter, 30 cm in plant height, 4 fruits and 1.1 °Brix, with respect to the best parent for each variable; this suggests that it would be possible to use LA1223 to broaden the genetic base in the improvement of this vegetable.

The increasing demand for fresh produce traditionally consumed by members of the Latino community in their countries of origin provides an opportunity to produce these specialty crops in the Northeastern region of the United States. In Massachusetts, more commercial farmers are interested in growing vegetables common in Latin America. One example is chipilín (Crotalaria longirostrata Hook. & Arn.), a leguminous leafy green native to South and Central America. Preliminary studies indicate that this crop requires nitrogen (N) applications as high as 200 kg·ha^-1 to achieve the quality standards required to market this vegetable. The objective of this study was to evaluate the capacity of specific Rhizobia strains to colonize chipilín roots and estimate the N supplied by the bacterial colonization and its impact on quality traits and economic yield. The effects of N supplied by biological fixation in plants inoculated with different Rhizobia species were evaluated. Rhizobium leguminosarum biovar colonized chipilín and enhanced the total fresh weight of the crop by 158 kg·ha^-1. Supplementary applications of inorganic N had little effect on the efficiency of colonization by the bacterial strains. Furthermore, applying more than 80 kg·ha^-1 of N increased only the green color of the leaves and was economically inefficient in increasing the total fresh weight of the crop. Thus, inoculations with Rhizobium leguminosarum biovar can be integrated into a sustainable production system for complementing or replacing chemical fertilizers and preventing deleterious effects on the environment.

Breeding programs should consider, in addition to agronomic aspects (yield, crop cycle, resistance to diseases and pests, among others), aspects related to suitability for use and quality of the final product, since consumer acceptance depends on them. Therefore, the objective of this research was to characterize 24 potato (Solanum tuberosum) genetic materials, considered promising for frying, and a commercial control based on physical (dry matter content, specific gravity and color) and chemical (total polyphenols, total antioxidant capacity and polyphenol oxidase activity) quality parameters. Differences were found in dry matter content, where three genetic materials (07032.3, 10025.1 and 07062.1), with values less than 20 %, would not be suitable for frying, but for cooking. Specific gravity was similar among genetic materials, proving to be a parameter not as strict for selection as dry matter content. Differences were observed in polyphenol oxidase activity (2.1 to 101.43 U∙g_protein^-1a in dry weight [DW]) and frying color. Of all materials analyzed, 10 are promising for frying, while the rest have problems with low dry matter content (15.5 to 17.19 %), high polyphenol oxidase activity (> 45 U∙g_protein^-1a in DW) and non-golden or dark color, which would make them less attractive to both industry and consumers.