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Petrolina de Goiás, Brazil

Bassoi L.H.,Embrapa Tropical Semi Arid
Acta Horticulturae | Year: 2011

The wine grape production in the tropical zone, and in particularly in the Brazilian semi-arid region, is dependent on irrigation practice due to insufficient rainfall and irregular distribution over three to four months in a year. Drip irrigation systems as well as vertical trellis system are predominant for wine grapes in this region. Some of the irrigation management guidance in practice in the field is based on previous experience and knowledge from other regions with some climate similarities, like USA (California) and Australia. As a relatively new crop in the Brazilian semi-arid region, first research results about irrigation scheduling or strategies in wine grapes are recent. Irrigation strategies as deficit irrigation, regulated deficit irrigation and partial rootzone drying have been evaluated. Therefore, research efforts in the Brazilian semi-arid region should be addressed to water consumption by scion/rootstock varieties, as well as ecophysiological behavior, berry and wine characteristics influenced by water management, according to local edaphic and climatic conditions. Source

De Teixeira A.H.C.,Embrapa Tropical Semi Arid | Hernandez F.B.T.,University of Sao Paulo
Acta Horticulturae | Year: 2012

Weather data for 2011, from a net of 15 automatic agro-meteorological stations and previous field energy balance results, were used together with regression models for modelling the guava water requirement (GWR) in the growing area of Petrolina (Pernambuco state) - Juazeiro (Bahia state), Brazil, considering a 6.5-months average growing season (GS). GWRGS joined with rainfall, allowed the acquirement of the regional water balance and the application of a guava water indicator (GWIGS) calculated as the ratio of the total precipitation during a growing season (PGS) to GWRGS. The variation of the averaged GWRGS values for Petrolina, was from 750±6.9 to 950±10.5 mm, while for Juazeiro, it was from 730±6.2 to 900±9.2 mm, with pruning periods in January and June, respectively. Considering the GWIGS indicator, its values for both municipalities were found similar, which were around 0.38 and 0.08 for pruning done in January and June, respectively. Quantifying the differences between PGS and GWRGS, it was evident that a higher amount of irrigation water needed to be applied between September and October for growing cycles starting in June. Additional data from IBGE (Brazilian Geographical and Statistical Institute) allowed the inspection of the guava water productivity (GWP) at the municipality level. The GWP values for Petrolina were 4.1 and 3.3 kg m-3, while for Juazeiro they were 1.8 and 1.5 kg m-3, for pruning periods in January and June, respectively. It could be concluded that the lower GWP values for Juazeiro was because of a poorer crop management, resulting in lower yield, evidencing scope for improvements. The analyses spatially presented, can subsidize water allocation and irrigation management criteria, when aiming improvements on guava water productivity and yet, avoiding environmental damage by the fast climate and land use changes in the Brazilian semi-arid areas. © ISHS. Source

Da Costa S.R.,State University of Feira de Santana | Santos C.A.F.,Embrapa Tropical Semi Arid | Castro J.M.C.,Embrapa Tropical Semi Arid
Acta Horticulturae | Year: 2012

Commercial guava orchards have been destroyed in the São Francisco river Valley, northeastern Brazil, by the Meloidogyne enterolobii nematode but to date no effective control has been identified. The objective of the present study was to obtain and assess interspecific hybrids between Psidium guajava × P. guineense for tolerance to M. enterolobii, for use as guava rootstock or in genetic studies. Crossings were made between P. guajava GUA 161 PE accession and the P. guineense ARA 138 RR and ARA 153 BA accessions. The crossings were made when the calyx ruptured on the flower buds, and two SSR microsatellite markers were used to confirm the hybridization. When the plants reached 15 to 20 cm in height, they were inoculated with a suspension containing 10,000 nematode eggs. Four months after inoculation, the soil was removed from the plants and individual evaluation was carried out for the number of galls, number of eggs and reproductive factor (RF). The plants in the two crossings were considered as hybrids when genotyped with the mPgCI 251 and mPgCI 252 loci. The 10 plants from the 161 PE × ARA 138 RR cross assessed were tolerant to the nematode, with gall index and RF equal to zero. Seven of the 10 plants of the GUA 161 PE × ARA 153 BA cross assessed were considered susceptible to the nematode. The results suggested variability for tolerance among P. guineense accessions and that tolerance to the nematode could be conferred by a dominant allele. Plants of the interspecific hybrid grew similarly to the guava trees at eight months of age in field and were highly compatible with 'Paluma' guava, indicating that this strategy can present excellent results in controlling M. enterolobii. © ISHS. Source

Gava C.A.T.,Embrapa Tropical Semi Arid | Pinto J.M.,Embrapa Tropical Semi Arid
Biological Control | Year: 2016

The control of melon wilt caused Fusarium oxysporum f. sp. melonis (Fom) has become a complex problem for melon (Cucumis melo L.) growers worldwide. In this study, we evaluated the ability of Trichoderma spp. to control melon wilt under field conditions, and the application of liquid compost as a food-based strategy to improve the biocontrol efficiency of the selected strain. In a first experiment, we evaluated the use of Trichoderma harzianum LCB47, Trichoderma viride LCB48, Trichoderma koningii LCB49, and Trichoderma polysporum LCB50 to control melon wilt in a naturally infested soil. The treatment with T. polysporum LCB50 (Tp) showed the highest efficiency to control melon wilt (44.85%), increasing the fruit yield in 43%. In the second experiment, Tp was applied as seed treatment, and repeated once at 15 days after transplanting. Two doses of liquid compost: 25 (LC25) and 50 mL pL-1 (LC50), were applied by fertigation on a weekly basis along the crop development. In this experiment, T. polysporum LCB50 applied alone resulted in a significant (< 0.05) control of wilt (32.2%), and 27% increase in fruit production. Single application of both doses of LC did not significantly reduced disease incidence. However, a strong synergistic effect was observed applying Tp and LC25 and LC50, resulting in a highly significant wilt control (68 and 72%, respectively) and an increase in productivity. The use of Tp + LC50 treatment increased in 100% the production of commercial fruits. From the results, a strategy based on the use of T. polysporum LCB50 and an organic matter source is proposed for the integrated management for melon wilt. © 2016 Elsevier Inc. Source

Santos C.A.F.,Embrapa Tropical Semi Arid | Correa L.C.,Embrapa Tropical Semi Arid
Acta Horticulturae | Year: 2012

Guava is an excellent source of antioxidant compounds due to its high content of phenolics, lycopene and vitamin C. The international guava market is dominated mainly by white guava, while red guava dominates the Brazilian market. The objective of this study was to analyze the content of Brazilian guava accessions contrasting for pulp colors to support the guava breeding program, focusing on accessions with high antioxidant compound contents. Sixty guava accessions established in a germplasm bank at Embrapa Tropical Semi-Arid, Brazil were evaluated for total antioxidant activity, phenolic compounds, ascorbic acid, flavonoids, lycopene, beta-carotene, titratable acidity, soluble solids and total soluble sugars. The accessions, including white (n=10), red (n=23) and pink (n=27) pulp fruits, were grown in a randomized block design, with two replications/accession. An ANOVA was performed with the degrees of freedom based upon the three pulp color groups. White guava did not present variability for the majority of compounds, except soluble solids. Red and pink guava presented high variability (p<0.01) for most compounds, except flavonoids in pink guava and flavonoids, beta-carotene, soluble solids and total sugars in red guava. The white*red + pink pulp contrasts were significant (p<0.01) for most compounds, except for titratable acidity and soluble solids, with greater mean values in the pink + red accessions, except for total soluble sugars. The red*pink contrasts were also significant (p<0.01), except for titrable acidity and soluble solids, with greater values in the red guava accessions, except for lycopene and total soluble sugars. The compound mean values were, approximately, 1.5×, 1.4×, 1.7×, 1.8×, 2.7× and 3.1× greater for antioxidant activity, phenolic compounds, ascorbic acid, flavonoids, lycopene and beta-carotene, respectively, in the pink + red guava than white guava accessions. These results indicated that pink and red guava accessions have a greater beneficial potential and should be targeted for breeding programs. © ISHS. Source

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