The genotypes evaluation in a germplasm bank is essential to determine their commercial or usefulness, as potential parents, in a breeding program. We aimed to detect the genetic diversity of 42 tomato genotypes of cherry type, belonging to the germplasm bank of the Federal University of Uberlândia and, also evaluate their behavior. The experiment was conducted in a greenhouse in randomized block design with 42 treatments and two replications. Ten quantitative traits of agronomic importance were evaluated. The genetic divergence was obtained by multivariate analysis, using the Mahalanobis distance with different clustering methods (UPGMA and Tocher). The hybrids performance was compared by Scott-Knott (p= 0.05) and Dunnett’s test (p= 0.05). UPGMA and Tocher grouped the genotypes similarly, representing genetic divergence satisfactorily. The genotypes UFU 29, UFU 21 and UFU 07 were more productive, earlier and also divergent from the pre-commercial treatment (UFU 200), being able to be used as potential parents.

ABSTRACT. The mini tomato production has expanded, becoming an amazing alternative for enterprise. Despite all commercial potential, the cultivation has the occurrence of pests as main obstacle during the crop development. Nowadays, there are no researches that aimed obtaining genotypes with high acylsugar content, capable of providing a broad-spectrum resistance to pests. This study aimed the selection of mini tomato genotypes, with high acylsugar content, and checking the resistance level to the silverleaf whitefly [Bemisia tabaci (Gennadius)] and to the two-spotted spider mites (Tetranychus urticae Koch). Sixteen genotypes were evaluated, from which 12 were on the generation F 2 BC 1 , originated from the interespecific cross between Solanum pennellii versus Solanum lycopersicum L. and 4 were check treatments, being three of cultivated tomatos (cv. Santa Clara, UFU-02, and UFU-73) and the wild accession LA-716 (S. pennellii). The variables analyzed were acylsugar content, repellency to the silverleaf whitefly, repellence to the two-spotted spider mites, and density of glandular trichomes. The genotypes UFU-22-F 2 BC 1 #9 and UFU-73-F 2 BC 1 #11 have high acylsugar content and both are resistant to the pests that were evaluated. New studies must be conducted seeking for inbred lines, obtained from the selected genotypes, aiming to get commercial hybrids with high acylsugar content.

Water stress can affect the yield in tomato crops and, despite this, there are few types of research aiming to select tomato genotypes resistant to the water stress using physiological parameters. This experiment aimed to study the variables that are related to the gas exchanges and the efficiency in water use, in the selection of tomato genotypes tolerant to water stress. It was done in a greenhouse, measuring 7 x 21 m, in a randomized complete block design, with four replications (blocks), being five genotypes in the FBC generation, which were previously obtained from an interspecific cross between Solanum pennellii versus S. lycopersicum and three check treatments, two susceptible [UFU-22 (pre-commercial line) and cultivar Santa Clara] and one resistant (S. pennellii). At the beginning of flowering, the plants were submitted to a water stress condition, through irrigation suspension. After that CO assimilation, internal CO, stomatal conductance, transpiration, leaf temperature, instantaneous water use efficiency, intrinsic efficiency of water use, instantaneous carboxylation efficiency, chlorophyll a and b, and the potential leaf water (Ψf) were observed. Almost all variables that were analyzed, except CO assimilation and instantaneous carboxylation efficiency, demonstrated the superiority of the wild accession, S. pennellii, concerning the susceptible check treatments. The high photosynthetic rate and the low stomatal conductance and transpiration, presented by the UFU22/FBC#2 population, allowed a better water use efficiency. Because of that, these physiological characteristics are promising in the selection of tomato genotypes tolerant to water stress.

Currently, the main control strategy for arthropod-pests in tomato cropping is the use of synthetic chemical insecticides and miticides. The study aimed to select tomato genotypes of Santa Cruz type, with determinate growth habit, which were rich in acylsugar and presented resistance to spider mite. The evaluated segregating populations were derived from interspecific crossing and were in the advanced generation F 2 BC 2. Genotypes were assessed for acylsugars content, present in leaflets, trichomes at abaxial and adaxial parts and a repellence bioassay to the mite was performed. It was found that the genotype UFU-102-F 2 BC 2 #13 stood out in comparison to the others, showing determinate growth habit, high acylsugar content and resistance to spider mite. It was also possible to obtain genotypes that were similar to the wild specie S. pennellii, regarding the acylsugar content.

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Brazilian watermelon productivity is not efficient when compared to the largest producer countries, due to abiotic and biotic factors. Some of the difficulties are because of a small number of studies on this crop in Brazil. The aim of this study was to evaluate the effects of plant density and fruit thinning on two commercial watermelon hybrids (Talisman and Youlie), using trials which were carried out in two different seasons (April - July and August - November). The experiment was conducted in Uberlândia-MG and consisted of two managements of fruit position (A-basal and B-distal) and four plant densities (3,000, 4,000, 5,000 and 6,000 plants/ha). In season 1, the distal management was the most productive in relation to all cultivation densities. The distal management shows higher productivity in both hybrids, with greater increase in mass, productivity and 0Brix content in hybrid Talisman, however with lower density, firmness and internal cavity compared to hybrid Youlie. Weather conditions determined the influence of fruit management on watermelon crop. Cultivation during the hottest period and with a better water supply (season 2), basal management (A) showed a performance similar to the distal management. At this time, hybrid Talisman surpassed hybrid Youlie concerning productivity, average mass, fruit density, firmness and internal cavity. In both seasons, higher densities are related to higher productivities. Hybrid Talisman showed higher productivity in cultivation from April to July (season 1) under distal fruit management.

ABSTRACT:The tomato crop adapts to different climatic conditions. However, the water stress, which is a relevant factor in the tomato cropping, can affect the productivity. This experiment aimed to estimate the genetic variability, after two backcrosses, and select tomato genotypes that are tolerant to water stress induced by mannitol. The advance of the generations was done on the field and the water stress test was done in laboratory atmosphere, in a completely randomized design with four replications. 17 genotypes, in the generation F 2 BC 2 , which were obtained from an interespecific cross between Solanum pennellii and Solanum lycopersicum L. and three check treatments, one resistant [wild access LA-716 (Solanum pennellii)] and two susceptible (cv. Santa Clara and UFU-650), were evaluated. After subjected to the osmotic potential of -0.3 Mpa, the seeds were evaluated for: germination percentage, standard germination percentage, first counting percentage, germination velocity index, average time of germination and initial and final length of radicle. As expected, the wild access, S. pennellii, was better than the susceptible check treatments. The genotype UFU102/F 2 BC 2 #71115 highlighted, compared to the others F 2 BC 2 genotypes and in relation to the three check treatments, susceptible (cv. Santa Clara and UFU-650) and resistant (S. pennellii). Analyzing the genetic diversity, 8 different groups were obtained, being an indicative of genetic variability between the evaluated genotypes. The variable %G contributed with 33.9% in the diversification of the genotypes, presenting as the most important criterion, to be evaluated in genetic diversity studies, in the tomato crop under water stress, induced by mannitol.

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