Introduction. Carotenoids have been described as possessing several important functional properties and health benefits. These properties make these compounds ideal for the always increasing functional food industry as well as for promoting the consumption of the natural products in which they are contained. Here, we report the first characterisation of the non-saponified carotenoid composition in fresh peach fruits and commercial peach juice and jam. Materials and methods. Fully mature yellow-fleshed peach fruits produced in Sicily were purchased at a local market; they were peeled and the pulp was analysed. Commercial peach juice and commercial peach jam from three different known manufacturers were also purchased at the local market. Both the juice and jam analysed were produced by local manufacturers from the same kind of fresh fruit studied in this work. After carotenoid extraction with organic solvents, the samples were analysed by a direct HPLC-DAD-APCI-MS methodology. Results and discussion. Three free carotenoids (zeaxanthin, β-cryptoxanthin and β-carotene) and three monoesters of β-cryptoxanthin were identified and detected in all the samples analysed. Interestingly, the carotenoid profile remained the same in all the samples, and it was not affected by the peach processing occurring during the production of the peach juice and jam. Moreover, small differences were observed in the relative contents of the identified components among the samples investigated.

Introduction. India is the largest producer of pomegranate in the world, with rich genetic diversity. The wide range of utility of pomegranate in human health, nutrition and livelihood security has triggered its heavy demand in India and other countries. At present, more than 300 germplasm accessions from indigenous and exotic sources are available in India, but meagre information on the physico-chemical properties of their fruits is available. In our study, the physico-chemical properties of varieties grown under a semi-arid climate were investigated. Materials and methods. Our study was carried out at the experimental farm of the National Research Centre on Pomegranate, Solapur, India, during the harvests of 2008–2009 and 2009–2010. Twenty pomegranate varieties were studied with respect to the physico-chemical properties of their fruits. Results and discussion. A considerable variation (coefficient of variation: 3.37% to 101.13%) was observed with respect to the 16 characters studied. The values ranged from 12.64 °Brix to 15.39 °Brix for TSS; 0.38% to 3.40% for acidity; 16.67 g to 27.82 g for 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. Fruit size, rind weight, total aril weight, 100-aril weight, juice weight and aril width were found to have a strong positive correlation (P < 0.01) with fruit weight. Based on the total index score obtained, the varieties ‘Bassein Seedless’, ‘Dholka’, ‘Ganesh’, ‘Jyoti’, ‘Kandhari’, ‘KRS’, ‘Mridula’ and ‘P-13’ were found to be suitable for processing and table purposes.

Introduction. Bacterial canker, caused by Pseudomonas syringae pv. syringae, is a damaging disease of stone fruit worldwide. The effects of rootstock, temperature and incubation duration on bacterial canker in peach were assessed using both field and laboratory inoculation assays. Materials and methods. Both field and laboratory experiments were conducted to study the effects of rootstock, temperature and incubation duration on disease severity in peach. All inoculations were achieved with P. syringae pv. syringae strain B3A. Bacterial inoculations were applied to 1-year-old shoots of peach trees [Prunus persica (L.) Batsch]. After inoculation, the inoculated shoots were allowed to incubate either under field conditions or in a cold room at different temperatures [constantly at 0 °C, constantly at 14.4 °C, and in a fluctuating temperature regime of 12 h at 0 °C (night) and 12 h at 14.4 °C (day)] for excised shoots. The lesions were determined 1 to 6 weeks after inoculation to determine the effect of incubation duration. Results and discussion. The field experiment using peach grafted on three rootstocks (Nemaguard, K119-50 and P30-135) showed that shoots on Nemaguard developed the longest lesions and shoots on K119-50 the shortest among all three rootstocks. Shoots on Nemaguard had significantly lower bark calcium and higher nitrogen concentrations than those on K119-50 and P30-135. A negative correlation was 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 inconsistent results. Shoots from Nemaguard developed significantly smaller lesions than those on K119-50 and P30-135. Shoots on Guardian and Lovell also developed significantly smaller lesions than those of shoots on K119-50 and P30-135. Temperature fluctuation during incubation (0 °C to 14.4 °C) had no effect on shoot lesion length compared with those incubated constantly at 14.4 °C, but produced significantly longer lesions than shoots incubated constantly at 0 °C. These inconsistent results suggest that, in the absence of major predisposing factors (i.e., ring nematodes or low soil pH), rootstocks may play a minor role in peach susceptibility to bacterial canker even under favorable disease development conditions.

Introduction. Plant water stress indicators have become valuable for moving towards deficit irrigation strategies 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 obtain actual ET (ETa). Predawn leaf water potential (Yp) can be related to relative transpiration (RT), the ratio between transpiration of a stressed plot (T) and transpiration of a well-irrigated plot (Tm). Estimating RT from Yp allows calculating ETa for determination of irrigation amounts, if deficit irrigation practices are used, as RT corresponds approximately to Ks. Materials and methods. RT and Yp were measured with the aim of establishing a relationship to estimate RT under moderate water stress for irrigation scheduling, in a peach orchard in south Portugal. RT was calculated using sap flow measurements (heat balance method) in two plots, one well-irrigated (daily drip irrigation amounts calculated for Tm) and another temporarily without irrigation. Results and discussion. A high correlation was found between RT and Yp, allowing the estimation of RT for the studied conditions. Significant differences regarding the relationship RT-Y p obtained for another peach orchard in the same region and similar soil conditions were found for Yp in the range between –0.11 and –0.45 MPa. The results suggest that the differences resulted from the different irrigation systems: drip and micro-sprinkling, as they determine different temporal and spatial water distribution and therefore different geometry of root systems. A formerly proposed equation to estimate RT from Yp with a general form for different fruit tree species was tested, proving to be adequate within some limits: when RT is lowered to 0.7, the error was below 9%. The threshold value RT = 0.7 was considered a minimum as it was successfully tested in deficit irrigation practices for peach orchards.

Introduction. Bacterial canker, caused by P. syringae pv. syringae, is an important disease of stone fruit worldwide. The possibility of P. syringae pv. syringae infection through leaf scars and lenticels was evaluated in cherry, peach and prune. Materials and methods. Laboratory and field inoculations were performed using cherry, peach and prune stems to evaluate leaf scar age, chilling and freezing-thawing on bacterial infection through leaf scars and lenticels. Results and discussion. Increasing leaf scar age was associated with significant decreases in disease incidence and length of lesions resulting from leaf scar inoculation with Pseudomonas syringae pv. syringae in cherry, peach and prune. A significant reduction in incidence and lesion length was observed after 4 h of air exposure, and both measures of infection were reduced to essentially 0 by 2 days of exposure. Prolonged chilling temperature (2.2 °C) prior to leaf removal had no clear effect on disease incidence of leaf scar infection, but significantly decreased lesion length due to leaf scar infection. Cherry was more susceptible to P. syringae pv. syringae infection through leaf scars than peach and ‘French’ prune. The leaf scar inoculation results were consistent with the previous studies. The disease incidence of 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 and the lesion size via lenticel infection. The lenticel inoculation data suggest that P. syringae pv. syringae infection through lenticels is possible under field conditions.