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About 50% of species of the botanical family Asteraceae have been studied in relation to their morphogenesis capacity in vitro; in the case of the genus Tagetes, only 5% of the species have been explored. Research on the in vitro culture of cells, tissues and organs of this genus was reviewed as a basic reference to explore other species, highlighting the critical role of factors involved in in vitro morphogenesis of Tagetes. Callogenesis is promoted by a ratio of auxin and cytokinin concentrations, and 2,4-dichlorophenoxyacetic acid is a frequent inducer of callus. Another auxin used successfully has been naphthaleneacetic acid. Organogenesis is influenced by the type of growth regulators and the auxin / cytokinin ratio. The best responses have been recorded using indoleacetic acid, naphthaleneacetic acid, benzyladenine and kinetin. The genotype is also important, since a relationship of growth regulators can induce shoots in one species or variety, but in another it can generate different responses. To induce direct organogenesis, gibberellins play an important role, since they inhibit callus formation. Embryogenesis is regulated by the auxin / cytokinin ratio; being 2,4-D, supplemented with benzyladenine the most used. These factors to induce morphogenesis basically correspond to domesticated species, and it is expected that such factors will be useful for ruderal, weed or wild species of this genus.

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The objective of this review is to highlight the potential and feasibility of the cultivation of native species of the sub-Andean Yungas, Physalis peruviana and P. pubescens, in Argentina. Both species produce fruits with similar characteristics, being almost indistinguishable. Some names of the fruit are Physalis, cape gooseberry, capulí, aguaymanto, Cape goosberry or goldenberry. It is an exotic fruit of worldwide growing interest, mainly for its nutraceutical properties and excellent prices in Europe and the US, where it is considered a "speciality" fruit. It grows in environments with thermal ranges from 5 to 35°C, with a base temperature of 6.29°C and an optimal temperature of 21°C, requiring a constant supply of water, with demands in the range of 1000 to 1800 mm of precipitation, well distributed throughout the year. The main pests are Epitrix cucumeris (Coleoptera), Chloridea (Heliothis) subflexa (Lepidoptera) and Liriomyza sp. (Diptera). The most important pathogen is Fusarium oxysporum, followed by Phoma sp., Pythium sp., Cercospora physalidis and Sclerotinia sclerotiorum. The fruit can be affected by postharvest pathogens such as Botrytis sp., Cladosporium, Pestalotia and Phomopsis. In Tucumán, INTA-Famaillá carried out adaptation tests with both Physalis species, verifying their agronomic viability. Argentina’s northwestern region has developed as an agro-export hub for fresh berries to the northern hemisphere, where the main consumer markets for goldenberry are located, constituting an opportunity. The processing of goldenberry allows the production of stable, sensory-pleasant products, broadening the possibilities of commercialization, and allowing the addition of value (pulp, nectars, juices, jams, dehydrated products, energy bars, sauces, ice cream, etc.).

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Tomato intercropping with antagonistic species is considered a management alternative for Meloidogyne spp. The objective of the work was to evaluate the intercropping of Tagetes erecta, Tagetes minuta and Crotalaria juncea for the management of Meloidogyne spp., in tomato cultivation. The gall index and the number and weight of fruits were determined in tomato plants. Tomato intercropping with T. erecta showed a lower gall index than the rest of evaluated treatments. In addition, a higher weight and number of fruits were observed in this treatment and in the one with T. minuta, respect to the C. juncea treatment and the control without intercropping. Under the conditions of this trial, intercropping of tomato with T. erecta proved to be a good alternative for the management of Meloidoigyne spp. This practice contributes to a lesser use of phytosanitary products, with the positive effect that it has on the environment, and to the obtaining of a more innocuous horticultural product for human consumption.

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Measurement of plant physiological response to stress or practices for its alleviation is useful for non-destructive evaluation and early diagnosis. The aim of this work was to study physiological effect of the use of phytohormones on tomato crop in soil infested by Nacobbus aberrans. The essay was carried out under a greenhouse located in EE Julio Hirschhorn (La Plata, Buenos Aires). Tomato Elpida was treated by drench, 24 hours pre-transplanting with 1 ml of: salicilic acid 0.50 x 10-4 M and 1.00 x 10-4 M, ethylen 0.35 x 10-3 M and 0.70 x 10-3 M, jasmonic acid 1.00 x 10-4 M and 1.00 x 10-5 M, using plants without treatment as control. It was recorded gas exchange: CO2 net assimilation rate, stomatal conductance, transpiration and instant water use efficiency, leaf temperature and greenness index. Statistical design was a randomized complete block with 4 replications. Variance analysis and Tukey test were applied. Gas exchange was not modified by treatments. Leaf temperature was significant lesser with salicylic acid 1.00 x 10-4 M, which increased the greenness index; variable that was lower in control plants. Increasing resistance in tomato against N. aberrans by salicylic acid and the measurement of physiological variables to check the response of the plant are promising possibilities.

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Our objective was to evaluate the suppression of root infection by the nematode Meloidogyne incognita in tomato roots previously colonized by arbuscular mycorrhizal fungi (HMA) native of Buenos Aires Province. Tomato plants were inoculated at sowing with a consortiumcontaining HMA= HMA0, HMA50 and HMA100 corresponding to 0, 50% and 100% of substrate with HMA (8 replications). At 40 days, inoculated plants showed HMA colonization higher than 60%. Plants were transplanted and each treatment was inoculated or not with M. incognita (4 replications of each nematode inoculation treatment). At harvest (115 days of growth) plants inoculated with HMA without nematodes showed mycorrhizal colonization higher than 90%. Although plants inoculated with nematodes showed decreases of mycorrhizal colonization, the obtained levels were higher than colonization prior to transplant. Inoculation with HMA decreased both soil abundance of nematode larvae (j2) and number of root galls. Although aerial growth of tomato was not affected by inoculation (HMA or nematodes), HMA0 plants (independently of nematode inoculation) showed higher root growth, that can be considered a strategy of the plant in order to compensate the lower volume of root exploration in the absence of HMA hyphae. Our results showed reduction of nematode density (j2, galls and egg masses) after inoculation of tomato with HMA. It may be concluded that the adequate establishment of mycorrhizal colonization prior to infection with nematodes exerts an apparent control of the infection of the M. incognita nematode in tomato roots. It could be a strategic tool for the biological control of pathogens of horticultural crops.

Evaluation of yield and health parameters of two commercial tomato hybrids (Solanum lycopersicum L.) grafted on Solanun sisymbriifolium (Lam.), in a greenhouse with biosolarizated soil

HORTICULTURE | Mitidieri, M.S. - Piris, E. - Brambilla, V. - Barbieri, M. - Cap, G. - González, J.D. - Del Pardo, K. - Ciapone, M. - Celié, R. - Arpía, E. - Paunero, I.E. - Peralta, R. - Verón, R. - Sanchez, F.

Tags: Rootstock, biosolarization, Nacobbus aberrans, Fusarium spp

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The use of plants grafted on resistant rootstocks can help to reduce losses caused by biotic and abiotic factors. This experience evaluated the performance of Solanum sisymbriifolium Lam. (popularly named “tutiá”) as a rootstock in combination with two commercial tomato hybrids. Genetic materials evaluated were Elpida and Superman, grafted on “tutiá” (ELPg, SUPg) and the same materials without grafting (ELP, SUP). Plants were transplanted (august/2012) in a greenhouse into biosolarizated plots (treated November/2011) and into control plots without soil disinfection. A split splot experimental design with four replicates in blocks was used. ELP y SUP showed higher yields (kg·plant-1) (30.6 % higher general mean), than ELPg y SUPg. In control plots, grafted plants had better performance with means of ELPg = 4.53 ± 1.27, SUPg = 4.19 ± 1.49, SUP = 2.49 ± 0.28 and ELP = 1.89 ± 0.68. Grafted plants also showed less blossom end rot percentage (P < 0.01) and dead plants (DP) at the end of the crop cycle (P < 0.01) than no grafted plants, means for DP were SUPg = 18.80 ± 12.40, ELPg = 23.44 ± 7.55, SUP = 43.19 ± 9.64 and ELP = 46.00 ± 9.12. Roots of grafted plants had higher total dry matter weight (P < 0.05) and lower rots percentages (P < 0.01) caused by Fusarium spp., although gall number caused by Nacobbus aberrans did not differ. The use of Solanum sisymbriifolium as rootstock could be considered a tool for integrated tomato pest management.

PDF 518 KB (439 downloads)

At the EEA La Consulta, INTA, a molecular assisted breeding program for processing tomatoes started in 2001 with the aim to generate self-pollinated cultivars, specially oriented for small growers. One of the main objectives of breeding program is the introduction of resistance to nematodes (Meloidoyne incognita, M. arenaria y M. javanica), tomato spotted wild virus (TSWV) and, tomato speck (Pseudomonas tomato syringae pv. tomato) as an alternative to use foreign and expensive hybrids cultivars. Breeding lines were obtained by pedigree and backcross selection methods. Early selection of resistant plants was done using molecular markers linked to nematode and TSWV. Molecular marker determinations were performed by the Laboratory of Molecular Biology of the INTA-Faculty of Agricultural Sciences (UNCuyo). Advanced breeding lines were tested against commercial hybrids in the Tomato 2000 Program. From all the materials evaluated up to 2010-11, we have identified homozygous lines that combine resistance to nematodes and tomato spotted wilt virus; homozygous lines that combine resistance to nematodes, tomato spotted wilt virus and tomato speck and homozygous lines resistant to nematodes, tomato spotted wilt virus and tomato speck (in separate genotypes). Also, heterozygous lines in different combinations for the genes under study. In comparative trials, the yiel (kg·ha-1) of the new lines did not have significant differences from controls. Horticultural recommendations are discussed.