Introduction. India is thelargest producer of pomegranate in the world, with rich geneticdiversity. The wide range of utility of pomegranate in human health,nutrition and livelihood security has triggered its heavy demandin India and other countries. At present, more than 300 germplasmaccessions from indigenous and exotic sources are available in India,but meagre information on the physico-chemical properties of their fruitsis available. In our study, the physico-chemical properties of varietiesgrown under a semi-arid climate were investigated. Materialsand methods. Our study was carried out at the experimentalfarm of the National Research Centre on Pomegranate, Solapur, India,during the harvests of 2008–2009 and 2009–2010. Twenty pomegranatevarieties were studied with respect to the physico-chemical propertiesof their fruits. Results and discussion. A considerablevariation (coefficient of variation: 3.37% to 101.13%) was observedwith respect to the 16 characters studied. The values ranged from 12.64 °Brixto 15.39 °Brix for TSS; 0.38% to 3.40% for acidity; 16.67 g to 27.82 gfor 100-aril weight; 4.31-38.62 for the maturity index; 59.22% to 77.40%for aril percentage; and 43.30% to 61.00% for juice percentage. Fruitsize, rind weight, total aril weight, 100-aril weight, juice weight andaril width were found to have a strong positive correlation (P < 0.01) withfruit weight. Based on the total index score obtained, the varieties ‘BasseinSeedless’, ‘Dholka’, ‘Ganesh’, ‘Jyoti’, ‘Kandhari’, ‘KRS’, ‘Mridula’and ‘P-13’ were found to be suitable for processing and table purposes.

Introduction.Saskatoon berry (Amelanchier alnifolia Nutt.) isa promising fruit species originating from North America. Amongpomaceous fruits, saskatoon berries are a valuable source of chemicalcompounds with an antioxidant effect. Materials and methods.The total phenolic content, total flavonoid content and their correlationassociated with the total antioxidant capacity of fruit of fiveparticular cultivars were ascertained. Reactive oxygen species (specificallynitric oxide, superoxide anion and hydroxyl radical) and antioxidantactivity in the liver lipid system of their methanolic extractswere also assessed. Results and discusssion. In saskatoonberry cultivars the total contents of phenolic compounds rangedfrom (2.52 to 3.82) g gallic acid Eq·kg–1 of fresh mass, while thevalues of total antioxidant capacity were observed to be from (4.17to 5.29) g of ascorbic acid Eq·kg–1 of fresh mass. High correlationcoefficients between phenolics as well as flavonoids and antioxidant capacitywere calculated (r2 = 0.8921 and r2= 0.9901, respectively). Nitric oxide, superoxide anion, hydroxylradical and antioxidant activity in the liver lipid system of saskatoonberry fruit methanolic extracts (10%) were provided for the firsttime. In the case of nitric oxide, the inhibitions were 21.08–27.52%;as regards superoxide anion, they were 25.14–30.73%; concerning hydroxylradical, 18.25–21.18%, and in respect of antioxidant activity inthe liver lipid system, 7.90–8.38%. These inhibitions are strongerthan, e.g., in apples which are the most importantspecies of pomaceous fruit worldwide. Conclusions.Saskatoon berry fruit could be a suitable supplement for modern humannutrition. Furthermore, our work contributes to the popularisationof this pomaceous species, with the focus on its potential in relationto high antioxidant strength.

Introduction. Bacterial canker, caused by Pseudomonassyringae pv. syringae, is a damaging disease of stone fruitworldwide. The effects of rootstock, temperature and incubation duration on bacterialcanker in peach were assessed using both field and laboratory inoculation assays.Materials and methods. Both field and laboratory experiments were conductedto study the effects of rootstock, temperature and incubation duration on disease severityin peach. All inoculations were achieved with P. syringae pv.syringae strain B3A. Bacterial inoculations were applied to 1-year-oldshoots of peach trees [Prunus persica (L.) Batsch]. After inoculation,the inoculated shoots were allowed to incubate either under field conditions or in a coldroom at different temperatures [constantly at 0 °C, constantly at 14.4 °C, and in afluctuating temperature regime of 12 h at 0 °C (night) and 12 h at 14.4 °C (day)] forexcised shoots. The lesions were determined 1 to 6 weeks after inoculation to determinethe effect of incubation duration. Results and discussion. The fieldexperiment using peach grafted on three rootstocks (Nemaguard, K119-50 and P30-135) showedthat shoots on Nemaguard developed the longest lesions and shoots on K119-50 the shortestamong all three rootstocks. Shoots on Nemaguard had significantly lower bark calcium andhigher nitrogen concentrations than those on K119-50 and P30-135. A negative correlationwas found between lesion length and bark calcium concentration and the [calcium/ nitrogen] ratio. Laboratory experiments with excised shoots on Nemaguard, K119-50,P30-135, Lovell and Guardian rootstocks growing in a second orchard showed inconsistentresults. Shoots from Nemaguard developed significantly smaller lesions than those onK119-50 and P30-135. Shoots on Guardian and Lovell also developed significantly smallerlesions than those of shoots on K119-50 and P30-135. Temperature fluctuation duringincubation (0 °C to 14.4 °C) had no effect on shoot lesion length compared with thoseincubated constantly at 14.4 °C, but produced significantly longer lesions than shootsincubated constantly at 0 °C. These inconsistent results suggest that, in the absence ofmajor predisposing factors (i.e., ring nematodes or low soil pH),rootstocks may play a minor role in peach susceptibility to bacterial canker even underfavorable disease development conditions.

Introduction. Plant water stressindicators have become valuable for moving towards deficit irrigationstrategies and saving water. In this case evapotranspiration (ET)is below its maximum value for the crop and stage (ETc),and a stress coefficient (Ks) is applied to obtainactual ET (ETa). Predawn leaf waterpotential (Yp) can be related to relative transpiration(RT), the ratio between transpiration of a stressedplot (T) and transpiration of a well-irrigatedplot (Tm). Estimating RT fromYp allows calculating ETa fordetermination of irrigation amounts, if deficit irrigation practicesare used, as RT corresponds approximately to Ks. Materials and methods. RT and Yp were measuredwith the aim of establishing a relationship to estimate RT undermoderate water stress for irrigation scheduling, in a peach orchardin south Portugal. RT was calculated using sap flowmeasurements (heat balance method) in two plots, one well-irrigated(daily drip irrigation amounts calculated for Tm) andanother temporarily without irrigation. Results and discussion. Ahigh correlation was found between RT and Yp,allowing the estimation of RT for the studied conditions.Significant differences regarding the relationship RT-Yp obtained for another peach orchard in the sameregion and similar soil conditions were found for Yp inthe range between –0.11 and –0.45 MPa. The results suggest that thedifferences resulted from the different irrigation systems: dripand micro-sprinkling, as they determine different temporal and spatialwater distribution and therefore different geometry of root systems.A formerly proposed equation to estimate RT fromYp with a general form for different fruit treespecies was tested, proving to be adequate within some limits: when RT is lowered to 0.7, the error was below 9%. Thethreshold value RT = 0.7 was considered a minimumas it was successfully tested in deficit irrigation practices for peachorchards.

Introduction. Bacterial canker,caused by P. syringae pv. syringae,is an important disease of stone fruit worldwide. The possibilityof P. syringae pv. syringae infectionthrough leaf scars and lenticels was evaluated in cherry, peachand prune. Materials and methods. Laboratory and fieldinoculations were performed using cherry, peach and prune stemsto evaluate leaf scar age, chilling and freezing-thawing on bacterialinfection through leaf scars and lenticels. Results and discussion. Increasingleaf scar age was associated with significant decreases in diseaseincidence and length of lesions resulting from leaf scar inoculationwith Pseudomonas syringae pv. syringae incherry, peach and prune. A significant reduction in incidence andlesion length was observed after 4 h of air exposure, and both measuresof infection were reduced to essentially 0 by 2 days of exposure. Prolongedchilling temperature (2.2 °C) prior to leaf removal had no cleareffect on disease incidence of leaf scar infection, but significantlydecreased lesion length due to leaf scar infection. Cherry was more susceptibleto P. syringae pv. syringae infectionthrough leaf scars than peach and ‘French’ prune. The leaf scar inoculationresults were consistent with the previous studies. The disease incidenceof lenticel infection caused by bacterial inoculation in ‘French’prune was very low, but significantly higher than the water control.Freezing-thawing significantly increased both the disease incidence andthe lesion size via lenticel infection. The lenticel inoculationdata suggest that P. syringae pv. syringae infection throughlenticels is possible under field conditions.