Responses of tomato hybrid cultivars to soil application of humic acid under greenhouse conditions

Responses of three tomato (Lycopersicon esculentum Mill.) hybrids viz. 'Luanova', 'Savarona' and 'Tessera' to various doses (0, 0.5, 1.0, 1.5 and 2.0 g L-1) of soil application of humic acid (HA) were evaluated in terms of plant growth, productivity and quality of fruits, under greenhouse conditions, during 2011-12 and 2012-13. In addition to improved quality characteristics, higher values for yield and yield components were recorded for tomato fruits harvested from plants of 'Tessera' cultivar compared to those harvested from other hybrids tested, regardless of growing seasons. Plants from 'Luanova' cultivar were, however, earlier in fruiting with higher number of fruits per plant. Soil application of HA presented positive effects on yield and physicochemical quality of tomato fruits irrespective of the dose of HA and the cultivar investigated, in both seasons. Soil application of HA at higher dose 1.5 g L-1 exhibited better results in all the three tomato cultivars tested, in terms of their vegetative and reproductive growth, and significantly improved the physicochemical quality of their fruits. Conclusively, the tomato hybrid 'Tessera' was found suitable for cultivation under greenhouse conditions while soil application of aqueous solution of HA @ 1.5 g L-1 substantially resulted in higher production of quality tomato fruits.

Nutritional Characterization of a Traditional Cultivar of Tomato Grown Under Organic Conditions—cv. “Malacara”

The loss of genetic diversity due to the replacement of local tomato (Solanum lycopersicum L.) varieties by improved cultivars has been mitigated in many cases by the good work of organic farmers in maintaining local agricultural biodiversity. In parallel to these initiatives, in recent years, consumers have developed an increasing awareness of both food-related health, environmental issues, and food demand to recover the flavors of the past. In the case of tomatoes, these attributes (nutritional, organoleptic, social, and environmental) are closely related to organic production using local varieties. “Malacara” tomato is an example of a local variety. Coming from Sierra de Cádiz, it is a varietal type called “Cuelga” (“for hanging,” because the tomato trusses are hung from beams in the farmhouses). Cultivated and harvested in the open air during the summer months, these tomatoes are commercialized and consumed in the winter. Historically, this variety has enabled the fresh consumption of tomatoes during the winter, without the need to force cultivation. It is highly appreciated in the local cuisine and is the basis for sauces figuring in typical dishes. Its characteristic traits are small, pallid fruits, and long shelf life. The main objective of this work has been to typify two Malacara tomato cultivars (red and yellow color) grown under organic farming conditions, through the characterization of morphological, nutritional, and volatile parameters. The main differences are due to morphological parameters (fruit weight and color of the exocarp and endocarp). Other characteristics such as the content of ash, fiber, moisture, the concentration of iron, magnesium, and calcium, and content of lycopene are different between both cultivars. This study provides information on the nutritional and aromatic composition of two Malacara tomato cultivars, differentiated by their color and grown under organic farming conditions. The results add value to the native horticultural heritage and can aid in the selection of tomato varieties suitable for a sustainable production system and to produce tomatoes with high nutritional value and rich in aroma.

Jasmonate and Melatonin Act Synergistically to Potentiate Cold Tolerance in Tomato Plants

Both jasmonic acid (JA) and melatonin (MT) have been demonstrated to play positive roles in cold tolerance, however, whether and how they crosstalk in the cold responses in plants remain elusive. Here, we report that JA and MT act synergistically in the cold tolerance in tomato plants (Solanum lycopersicum). It was found that JA and MT were both substantially accumulated in response to cold stress and foliar applications of methyl jasmonate (MeJA) and MT promoted cold tolerance as evidenced by increased Fv/Fm, decreased relative electrolyte leakage (EL) and declined H2O2 accumulation in tomato plants. Inhibition of MT biosynthesis attenuated MeJA-induced cold tolerance, while inhibition of JA biosynthesis reduced MT accumulation in tomato plants under cold conditions. Furthermore, qRT-PCR analysis showed that the expressions of two MT biosynthetic genes, SlSNAT and SlAMST, were strongly induced by MeJA, whereas suppression of SlMYC2, a master JA signaling regulator, abated the expressions of SlSNAT and SlAMST under cold stress. Additionally, suppression of SlMYC2 reduced MT accumulation, decreased Fv/Fm and increased EL in cold-stressed tomato plants. Interestingly, exogenous MT promoted JA accumulation, while inhibition of MT biosynthesis significantly reduced JA accumulation in tomato plants under the cold condition. Taken together, these results suggest that JA and MT act cooperatively in cold tolerance and form a positive feedback loop, amplifying the cold responses of tomato plants. Our findings might be translated into the development of cold-resistant tomato cultivars by genetically manipulating JA and MT pathways.

Caracterización fisicoquímica y vida postcosecha de tres cultivares de jitomate (lycopersicum esculentum mil.) (SOLANACEAE) / Physicochemical characterization and postharvest life of three tomato cultivars (lycopersicum esculentum mill.) (SOLANACEAE)

El tomate es la hortaliza de fruto más cultivadas a nivel mundial. De esta existen múltiples genotipos, que están genéticamente creados para condiciones ambientales muy específicas, por ello es importante conocer el comportamiento postcosecha de los frutos, que resultará en el cultivar mejor recomendado para cada región. El objetivo general fue: realizar la caracterización fisicoquímica y postcosecha de tres genotipos de jitomate, cultivados bajo condiciones de invernadero, en Tehuacán Puebla, México. La investigación se llevó a cabo en laboratorio. Los genotipos fueron: Merlisse, Maxcesa y Komet tipo bola, cultivados bajo invernadero. Las variables respuesta fueron: diámetro ecuatorial y polar, dinámica del peso de fruto, color de fruto, firmeza, contenido de Ca++ y K+ y vida postcosecha. El diseño utilizado fue completamente aleatorizado, cuyos tratamientos fueron los cultivares y siete repeticiones (3 x 7)= 21 unidades experimentales. Los resultados indican, que el mayor diámetro ecuatorial y polar así como pérdida de peso, fueron en Maxcesa, mientras que Komett, presentó la mayor firmeza y contenido de Ca++ y K+, siendo este último quien presentó la mayor vida de anaquel. De esta investigación se puede concluir, que el cultivar Komett, es quien mejor se adapta a las condiciones del valle de Tehuacán, Puebla.

Pathogenetic trial of boric acid in bean and tomato plants

Background: homeopathy is held in organic agriculture as a means to control disease and plagues. However, different from doctors, who have works on materia medica and repertories available to choose the most suitable homeopathic medicine for each patient, agronomists do not yet have an equivalent Homeopathic Materia Medica of Plants (HMMP) describing symptoms observed in plants. Aim: the aim of this study was to carry out a homeopathic pathogenetic trial (HPT) in plants comparing the effects elicited by boric acid in ponderable dose and dilution 6cH in two different plant species, namely bean and tomato cultivars. Methods: 4 tests were carried out, 2 on tomato and 2 on bean plants, which received 1 to 6 applications of treatments. Results: there were differences between both species regarding their sensitiveness to boric acid. None of the tomato plants that received Boron 6cH showed symptoms, differently from bean plants. On the other hand, in tests of ponderable doses of boric acid, tomato plants exhibited 3 symptoms more than bean plants. A higher number of bean plants exhibited symptoms with boric acid in ponderable dose than in dilution 6cH). Nos ensaios com feijoeiro, um maior número de plantas apresentou sintomas após o tratamento com ácido bórico na dose ponderal do que com ácido bórico 6cH. Conclusions: these results suggest that the elaboration of a HMMP must take into account the species in which symptoms were obtained. Moreover, HPTs in plants must be carried out with both ponderable doses and high dilutions in order for differences in sensitiveness among species be better identified.

Effects of Potassium Fertilization, Cultivar Specifics and Seedling Temperature Regime on Growth Parameters and Yield of Tomato (Solanum lycopersicum L.)

Background: Potassium fertilization shows beneficial effect on formation of tomato vegetative biomass and productivity. The purpose of this study was to determine the extent to which split potassium application and seedling temperature regime affects the growth parameters (leaf number, leaf area, fresh leaf weight and LAI) and yield of various tomato cultivars. Methods: A pot experiment was conducted to investigate the impact of single dose and split potassium fertilization treatments, cultivar specifics and seedling temperature regime on growth parameters and yield of tomato. Ten high yielding classic round shape tomato cultivars with determinate growth habitat were planted on Fluvisol. Single and split potassium fertilization treatments were tested. Result: The seedlings growth temperature regime and splitting the potassium fertilization treatment did not have a significant effect on the development of leaf biomass in tomato plants. Results revealed that leaf number, leaf area, fresh leaf weight and LAI of tomato plants was significantly affected by the cultivar genetic factor. Tomato yield were significantly affected by cultivars and split potassium fertilization treatments. Cultivars that measured the highest leaf area, fresh leaf weight and LAI and were also the highest yielding ones. A positive correlation between LAI and tomato fruit yield was observed.