• Authors:
    • Peridy, N.
    • Zouabi, O.
  • Source: Article
  • Volume: 133
  • Issue: 2
  • Year: 2015
  • Summary: North African countries (NACs) are particularly concerned with climate change because of their geographical position (close to deserts) and their economic dependence on agriculture. We aim to provide additional insight into the impact of climate on agriculture for NACs, through the example of Tunisia. We first use disaggregated data, both at the geographical level (for 24 regions in Tunisia) and at the product level (cereals, olives, citrus fruit, tomatoes, potatoes and palm trees). Second, through spatial panel data analysis, we explore both the time and spatial dimensions of the data. This makes it possible to consider spatial interactions in agricultural production and the role of climate in these spatial spillover effects. Finally, the model not only includes direct climate variables, such as temperature and precipitation, but also indirect climate-related variables such as the stock of water in dams and groundwater. Results show that Tunisian agriculture is strongly dependent on the direct effects of temperature and precipitation for all the products considered at the regional level. The presence of dams and groundwater generally has a positive effect on agricultural production for irrigated crops with interesting spillover effects with neighboring regions. However, this impact is still considerably lessened in the case of detrimental climate conditions (indirect effect). These results raise the question of the sustainability of the growth in agricultural production in Tunisia in the case of significant climate change.
  • Authors:
    • Ruberto, G.
    • Renda, A.
    • Strano, T.
    • Bosco, S.
    • Tusa, N.
    • Abbate, L.
  • Source: Food Research International
  • Volume: 48
  • Issue: 1
  • Year: 2012
  • Summary: Three new somatic hybrids, namely an allotetraploid hybrid and two cybrids (2n and 4n), have been obtained by protoplast fusion of 'Valencia' sweet orange ( Citrus sinensis L. Osbeck) + 'Femminello' lemon ( C. limon L. Burm.). The chemical composition of the essential oils of the hybrids and their parents has been studied by gas chromatography (GC) combined with a flame ionisation detector (FID) and a mass spectrometry (MS). In all, 87 components were fully characterised and grouped in four classes (monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpenes, and others) for an easier comparison of all oils. A statistical treatment by linear discriminant analysis of the compositional data from GC analyses was also carried out. The allotetraploid hybrid and both cybrids show an intermediate essential oil profile with respect to those of both parents. The contribution of 'Femminello' lemon parent is in all cases predominant in the production of the volatile profiles of the new hybrids; however, different behaviour in the peel essential accumulation between the allotetrapolid hybrid and the two cybrids is observed.
  • Authors:
    • Callado, S.
    • Albino, J.
  • Source: Emirates Journal of Food and Agriculture
  • Volume: 24
  • Issue: 4
  • Year: 2012
  • Summary: The article is based on an agro-ecological evaluation of seven different agricultural systems in Teresopolis, Rio de Janeiro. The studied systems are dealing with: vegetable production system, ecological husbandry, cattle production system, sylvopastoral approaches as well as citrus cropping systems. The main objective is to evaluate the environmental impact of these systems using the "Emergy Analysis" as methodology. For this purpose, input data as materials, services, natural renewable/nonrenewable sources of 42 crops were analyzed. This method is based on energy flows, transforming all inputs and outputs in a common unit. This analysis allows comparisons across agricultural systems and their environmental impacts, as well as, makes possible the identification of scenarios to achieve greater sustainability. The main conclusions of this study are: the vegetable systems have large amounts of energy invested in irrigation, fertilizers and fuels; the largest value of sustainability corresponds to the ecological systems and it has the capacity to save capital in form of biomass in the system; cattle system causes bigger environmental damage and have the smallest yield per hectare in economic and energy terms; as for the citrus systems, a low investment rate was found and the use of renewable resources from this system is comparable to the vegetable systems.
  • Authors:
    • Ollitrault, P.
    • Cuenca, J.
    • Juarez, J.
    • Aleza, P.
    • Navarro, L.
  • Source: Plant Cell Reports
  • Volume: 31
  • Issue: 9
  • Year: 2012
  • Summary: The citrus fresh market demands the production of seedless citrus fruits, as seedy fruits are not accepted by consumers. The recovery of triploid plants has proven to be the most promising approach to achieve this goal, since triploids have very low fertility, are generally seedless and do not induce seeds in other cultivars by cross pollination. Triploid plants can be recovered by 2x * 4x sexual hybridization. In this work, we present an effective methodology to recover triploid plants from 2x * 4x hybridizations based on in vitro embryo rescue, ploidy level analysis by flow cytometry and genetic origin of triploid plants. The pollen viability of diploid and tetraploid citrus genotypes was analyzed by comparing the pollen germination rate in vitro. The pollen viability of tetraploid (doubled-diploid) genotypes is generally reduced but sufficient for successful pollination. Triploid embryos were identified in normal and undeveloped seeds that did not germinate under greenhouse conditions. The influence of parents and environmental conditions on obtaining triploid plants was analyzed and a strong interaction was noted between the parents and environmental conditions. The parental effect on the length of the juvenile phase was also demonstrated through observations of a large number of progeny over the last 15 years. The juvenile phase length of the triploid hybrids obtained with 'Fortune' mandarin as female parent and tetraploid 'Orlando' tangelo as male parent was shorter than the juvenile phase obtained with a clementine as female parent and tetraploids of 'Nova', 'W. Leaf' and 'Pineapple' male parents.
  • Authors:
    • Bani-Hani, N.
    • Osaili, T.
    • Angor, M.
    • Ajo, R.
    • Al-Rousan, W.
  • Source: Journal of Food Agriculture & Environment
  • Volume: 10
  • Issue: 2 Part 1
  • Year: 2012
  • Summary: The effect of different irrigation levels on the Navel orange fruit quantity and quality was studied in the Jordan Valley through the 2007 and 2008 production seasons. Irrigation treatment consisted of control irrigation at 100% of crop evapotransperation and two deficit irrigation treatments. The latter irrigation treatments consisted of treatment at 75% of control irrigation, and at 50% of control irrigation. Fruits were harvested at five different periods, starting at the beginning of November in both seasons; harvesting took place at two-week intervals. The yield in both seasons of treatment at 75% of control irrigation was not affected significantly (p>0.05) compared with control. Yield of treatment at 75% of control irrigation was 36.1 t ha -1 and 26.17 t ha -1 in 2007 and 2008, respectively. As for control treatment, it was 35.17 and 28.15 t ha -1 for the same seasons. The yield of treatment at 50% of control irrigation was 29.16 t ha -1 for 2007 and 20.43 t ha -1 for 2008, indicating significant reduction (p≤0.05). Total soluble solids, titratable acidity, and their ratio increased when reducing water irrigation. At the same time, juice percent and vitamin C were not nearly significantly different. Yield increased as harvesting progressed up to the third harvesting period (beginning of December) and started to decline by mid December. Fruits harvested at different periods showed a slight increase of juice percentage. Total soluble solids, total soluble solids/titratable acidity, and pH value increased significantly. A decrease of titratable acidity and vitamin C occurred as harvesting approached the third period. The results showed identical trends in both production seasons. From these results, two main conclusions can be obtained. First, the implementation of the 75% deficit irrigation instead of full irrigation would be recommended to save water while sustaining the same quantity and quality of yield. Second, the third harvesting period (beginning of December) is the more profitable harvesting period for Navel oranges at the different irrigation levels.
  • Authors:
    • Ribeiro Junior, P.
    • Teixeira, M.
    • Coelho, R.
    • Armindo, R.
  • Source: ENGENHARIA AGRICOLA
  • Volume: 32
  • Issue: 3
  • Year: 2012
  • Summary: This study aimed to evaluate the spatial variability of leaf content of macro and micronutrients. The citrus plants orchard with 5 years of age, planted at regular intervals of 8*7 m, was managed under drip irrigation. Leaf samples were collected from each plant to be analyzed in the laboratory. Data were analyzed using the software R, version 2.5.1 Copyright (C) 2007, along with geostatistics package GeoR. All contents of macro and micronutrients studied were adjusted to normal distribution and showed spatial dependence. The best-fit models, based on the likelihood, for the macro and micronutrients were the spherical and matern. It is suggest for the macronutrients nitrogen, phosphorus, potassium, calcium, magnesium and sulfur the minimum distances between samples of 37; 58; 29; 63; 46 and 15 m respectively, while for the micronutrients boron, copper, iron, manganese and zinc, the distances suggests are 29; 9; 113; 35 and 14 m, respectively.
  • Authors:
    • Ohta, H.
    • Sumi, H.
    • Inafuku-Teramoto, S.
    • Taira, I.
    • Asikin, Y.
    • Takara, K.
    • Wada, K.
  • Source: Journal of Agricultural & Food Chemistry
  • Volume: 60
  • Issue: 32
  • Year: 2012
  • Summary: Citrus peels are important sources of various pleasant aroma compounds and valuable bioactive substances. To investigate differences in the composition and content of Shiikuwasha ( Citrus depressa Hayata) peels from different cultivation lines, the composition of volatile aroma components, flavanones, and polymethoxylated flavones (PMFs) in four Shiikuwasha cultivation lines was examined. The composition of volatile aroma components in cold-pressed extracts of Shiikuwasha peels was analyzed using gas chromatography-flame ionization detection and gas chromatography-mass spectrophotometry. The extracts contained mainly monoterpene hydrocarbons (93.40-97.25%), including limonene (46.52-68.26%) and gamma-terpinene (21.48-30.52%). Differences in the composition of volatile aroma compounds in the Shiikuwasha cultivation lines were revealed using principal component analysis. Additionally, the composition of flavanones and PMFs was determined using high-performance liquid chromatography methods. Neohesperidin (96.58%) was the predominant flavanone in 'Izumi kugani' peel, while the other peels had high hesperidin contents (89.26-98.66%). Moreover, the PMFs of Shiikuwasha peels were composed of nobiletin (56.74-64.77%) and tangeretin (23.17-34.70%).
  • Authors:
    • Intrigliolo, D.
    • Castel, J.
    • Ballester, C.
    • Castel, J.
    • Testi, L.
  • Source: Acta Horticulturae
  • Issue: 951
  • Year: 2012
  • Summary: Transpiration of well watered (C) and regulated deficit irrigated (RDI) trees was determined by means of the compensation heat pulse method during 2009 and 2010 in commercial citrus groves of 'Clementina de Nules' (CN) and 'Navel Lane Late' (NLL). In both species, sap flow (SF) was measured in two trees per treatment instrumented with two gauges per tree. CN trees were equipped with two different types of gauges (type1 shorter than type2) determining heat velocity from crossing time at four different xylem depths according to Green et al. (2003). In NLL oranges, all the gauges were identical and the data were processed according to the compensation heat pulse+calibrated average gradient (CAG) method (Testi and Villalobos, 2009). Plant water status was determined by midday stem water potential measurements (Psistem). Results showed that the absolute SF values, and especially those from type2 gauges in CN, clearly underestimated tree water use. Tree to tree variability registered in CN (CV=0.09) was lower than in NLL (CV=0.17) which also showed a 17% of within tree variability. The average nocturnal-to-diurnal sap flow ratio was between 7% and 13%. The evolution of relative SF (e.g. SF RDI/SF C) was in agreement with differences in Psistem (r 2=0.78 in CN and 0.84 in NLL). This SF ratio showed the expected decreasing trend during the water restriction period and the recovery when irrigation was reestablished to normal dose. Overall, the results show that sap flow sensors can detect plant water stress but they also highlight some of the problems for accurately measuring transpiration.
  • Authors:
    • Maringoni, A.
    • Verona, L.
    • Nesi, C.
    • Theodoro, G.
    • Brugnara, E.
  • Source: IDESIA
  • Volume: 30
  • Issue: 1
  • Year: 2012
  • Summary: The citrus canker, caused by Xanthomonas axonopodis pv. citri, is one of the main citrus diseases and has threatened the world's citriculture. In this study, the damage caused by citrus canker was quantified in a sweet orange culture, cv. Valencia [ Citrus sinensis (L.) Osb.], grafted over 15 year-old Rangpur lime ( C. limonia Osb.), in the municipality of Guatambu, SC, Brazil, in the crop of 2004/05. Evaluations of the number of fruits per plant (NF), fruit yield per plant (P), citrus canker incidence on the fruit (IFR), and incidence (IL) and severity (SV) of citrus canker on 80 leaves per orange tree were performed in the harvest period, applying diagrammatical scales. Plants had large variation in SV (0.16%-1.09%), IL (12.50%-56.25%) and IFR (12.30%-56.09%). Linear regressions were significant between IL * SV, NF * SV, P * IFR, and NF * IFR. There was no significant difference (p>0.05) between the mean estimated values of IL in different quadrants of the crowns of the orange trees (N, S, L and O). Each 1% increase in IFR reduced 2.16 kg and 21.3 fruits per tree.
  • Authors:
    • Silva, S.
    • Stuchi, E.
    • Mourao Filho, F.
    • Cantuarias-Aviles, T.
    • Espinoza-Nunez, E.
    • Bremer Neto, H.
  • Source: Scientia Horticulturae
  • Volume: 142
  • Year: 2012
  • Summary: Despite considerable research conducted on 'Tahiti' lime [ Citrus latifolia (Yu Tanaka) Tanaka] in several countries, few long-term studies have focused on rootstock effects on fruit production and quality under non-irrigated conditions. As for many other fruit crops, rootstock studies for 'Tahiti' lime are often based on the evaluation of several horticultural responses simultaneously, instead of considering multivariate statistical approaches which may provide with more comprehensive information. Consequently, a trial was installed to evaluate the horticultural performance of non-irrigated 'Tahiti' lime trees budded onto the following 12 rootstocks: 'HRS 801' and 'HRS 827' hybrids; 'Rubidoux', 'FCAV' and 'Flying Dragon' trifoliates; 'Sun Chu Sha Kat' and 'Sunki' mandarins; 'Cravo Limeira' and 'Cravo FCAV' 'Rangpur' limes; 'Carrizo' citrange, 'Swingle' citrumelo, and 'Orlando' tangelo. The trial was installed in 2001, in an 8 m * 5 m spacing with no supplementary irrigation. Measurements of yield, fruit quality oriented to different consuming markets, canopy volume and tree tolerance to drought, were performed. A multivariate cluster analysis identified both 'Rangpur' lime rootstocks as those inducing larger cumulative yield and higher percentage of fruits for the domestic market, with highest drought tolerance to the trees. Despite of their high susceptibility to drought stress under non-irrigated conditions, the 'Flying Dragon' and 'FCAV' trifoliate rootstocks performed outstandingly for 'Tahiti' lime, inducing higher yield efficiency, early bearing and larger percentage of high-quality fruits for foreign markets, with smaller trees more suitable for high-density plantings.