Characterization of Tunisian pomegranate (Punica granatum L.) cultivars using amplified fragment length polymorphism analysis

The amplified fragment length polymorphism (AFLP) analysis of DNA was used to characterize 34 pomegranate cultivars. By using a combination of six primers, a total of 327 markers were scored with a mean of 57.5. The high percentage of polymorphic bands (ppb) of 94.7 and the resolving power (R_p) collective rate value of 129.14 were scored. Data proved that the tested primers were informative to discriminate among cultivars and to survey the genetic diversity in this fruit crop. It has been assumed that the local pomegranate germplasm is characterized by a typically continuous genetic diversity. The derived dendrogram proved that cultivars are clustered independently from their geographical origin and their denomination. In addition, AFLP permitted the generation of a nearly unlimited number of molecular markers that are reliable in differentiating the cultivars and/or the polyclonal varieties.     

Seed characterisation of five new pomegranate (Punica granatum L.) varieties

This study evaluated the production of five new pomegranate varieties (ME14, ME15, PTO2, PTO7 and CRO1), being all indigenous to Southeastern Spain where the species shows high variability. A morphological and organoleptic characterisation of the edible portion of the seeds were investigated. Some chemical characteristics of the juice, including total soluble solids, pH, acidity and maturity index, were assessed. Morphological characteristics of both the edible and the woody portions of the seed were evaluated. Also productive and organoleptic characteristics of all varieties were considered, being ME14 and ME15 the highest yielders. Furthermore, PTO2 and CRO1 showed the heaviest seeds (both showing an average weight of 0.61 g) while ME15 the lightest one (0.37 g). Regarding seed juice content, there were significant differences among the evaluated varieties; whereas PTO2 and CRO1 showed the highest juice contents, PTO7 yielded the lowest one. However, the cultivar PTO7 showed a significantly higher acidity content than the others, along with the lowest maturity index at all. Finally, ME14 and ME 15 were very interesting because of their high production, large fruit size and excellent seed organoleptic characteristics.     

Morpho-pomological and chemical characterization of pomegranate (Punica granatum L.) genotypes in Apulia region,Southeastern Italy

A recent increasing demand in Western countries for pomegranate products by consumers is especially supported for the nutritional and medicinal characteristics, due to the antioxidant properties of this fruit. Some studies have been published on the morphological and biochemical characteristics of pomegranate fruits in some Mediterranean countries, but little information is available about the genotypes present in Italy and in particular in Apulia (Southeastern region of Italy). This study (2008–2009) evaluated morpho-pomological and chemical parameters of eight pomegranate genotypes localized in private small orchards. Significant differences were observed among the pomegranate genotypes for many of the parameters investigated. In particular, fruit weight ranged from 168.9 g (SouMol) to 574.9 g (SouOst), °Brix from 14.7 (ComTri) to 18.0 (SouMol), titratable acidity from 5.4 (ComMol) to 25.0 (SouTri) g/L. SouMol showed the highest polyphenols (97.1 mg/L) and vitamin C (236.3 mg/L) contents. Oil content of the seeds was between 5.90% and 10.30%, no differences have been observed for the fatty acid composition with conjugated linoleic acid (CLA) isomers as the most abundant fraction (81.23%). Considering all the evaluated parameters, and especially those referring to the organoleptic characteristics and antioxidants content, it must be stated that the best genotypes worthy to be considered from agricultural and industrial points of view were AdeSgi for fresh market and SouOst for the juice industry.     

Mass modeling of pomegranate (Punica granatum L.) fruit with some physical characteristics

Among physical characteristics, dimensions, mass, volume and projected areas are important parameters in sizing and grading systems. Fruits with the similar weight and uniform shape are desirable in terms of marketing value. Therefore, grading fruit based on weight reduces packing and handling costs and also provides suitable packing patterns. The different grading systems require different fruit sizing based on particular parameters. In this study pomegranate mass was predicted by applying different physical characteristics with linear and nonlinear models as three different classifications: (1) single or multiple variable regressions of pomegranate dimensional characteristics, (2) single or multiple variable regression of pomegranate projected areas and (3) estimating pomegranate mass based on its volume. The results showed that mass modeling of pomegranate based on minor diameter and three projected areas are the most appropriate models in the first and second classifications, respectively. In third classification, the highest determination coefficient was obtained for mass modeling based on the actual volume as R² = 0.99 whereas corresponding values were 0.93 and 0.79 for assumed pomegranate shapes (oblate spheroid and ellipsoid), respectively. In economical and agronomical point of view, suitable grading system of pomegranate mass was ascertained based on minor diameter as nonlinear relation M = 0.06c² − 4.11c + 143.56, R² = 0.91.     

Investigation of physico-chemical properties and antioxidant activity of twenty Iranian pomegranate (Punica granatum L.) cultivars

Pomegranate is one of the native fruits of Iran which contains high genetic resources, but there are insufficient information regarding properties of the fruit. The objective of the present study was to investigate the physcio-chemical characteristics and antioxidant activity of twenty pomegranate cultivars grown in Iran. This study showed that there were significant differences among the cultivars in all measured factors except the length/diameter ratio of fruit. The fruit weight, skin percentage, aril percentage and juice percentage were within the range of 196.89–315.28 g, 32.28–59.82%, 37.59–65% and 26.95–46.55%, respectively. The total soluble solids content varied from 11.37 (°Brix) to 15.07 (°Brix), pH values from 3.16 to 4.09, titratable acidity content from 0.33 g 100 g⁻¹ to 2.44 g 100 g⁻¹ and total sugars content from 13.23 g 100 g⁻¹ to 21.72 g 100 g⁻¹. The results also showed that the values of ascorbic acid ranged from 9.91 mg 100 g⁻¹ to 20.92 mg 100 g⁻¹. The total anthocyanins content was observed in pomegranate cultivars between 5.56  mg 100 g⁻¹ and 30.11 mg 100 g⁻¹. The level of total phenolics was varied from 295.79 mg 100 g⁻¹ to 985.37 mg 100 g⁻¹. The antioxidant activity of pomegranate cultivars was found between 15.59 and 40.72%. These data demonstrated that the cultivar was the main parameter which influences the physico-chemical properties and antioxidant activity in pomegranates.     

The effect of maturity,sunburn and the application of sunscreens on the internal and external qualities of pomegranate fruit grown in Australia

Consumer interest in pomegranate fruit (Punica granatum L.) is increasing in Australia as a result of its unique external and internal qualities. This work looked at the effect of applying sunscreen treatments to pomegranate fruit on the degree of sunburn damage and the effect of maturity and sunburn on the internal antioxidant concentration of the juice. The pomegranates, cultivar ‘Wonderful’ were grown in Condobolin, New South Wales, Australia.     

Nutrient-alginate encapsulation of in vitro nodal segments of pomegranate (Punica granatum L.) for germplasm distribution and exchange

The present paper demonstrates the potential of nutrient-alginate encapsulation of axenic nodal segments of pomegranate for synthetic seed technology, which could be useful in germplasm distribution and exchange. Nodal segments from in vitro shoot cultures derived from mature nodal explants (source A) or axenic cotyledonary nodes (source B) were encapsulated in calcium alginate hydrogel containing Murashige and Skoog's [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant 15, 473–497] medium (MS) supplemented with 4.44 μM benzyladenine (BA) and 0.54 μM naphthalene acetic acid (NAA). Of various concentrations of sodium alginate (1–6%) and the complexation solution of calcium chloride (50–125 mM), a combination of 3% sodium alginate and 100 mM calcium chloride was most suitable for formation of ideal synthetic seeds. Morphogenic response of encapsulated nodal segments to seven different planting media was evaluated. Encapsulated nodal segments of both the sources exhibited shoot development only in four selected media. Of the planting media evaluated, % sprouting (shoot development) was the highest in MS medium augmented with 4.44 μM BA and 0.54 μM NAA and lowest in (1/2) MSS medium. One step germination i.e. both shoot and root formation was possible only with encapsulated nodal segments of source B in MS, (1/2) MSS and natural soil + (1/2) MSS, with MS being most effective. Encapsulated nodal segments stored up to 30 days at 4 °C were capable of sprouting. Plants regenerated from the encapsulated nodal segments were hardened off and transferred to soil.     

Genetic diversity and population genetic structure of pomegranate (Punica granatum L.) in Iran using AFLP markers

Pomegranate (Punica granatum L.) is one of the oldest known edible fruits. It is native to Iran and spread from Iran to other areas. In this study amplified fragment length polymorphism (AFLP) was used to detect intra- and inter-population genetic diversity of pomegranate. A group of 67 accessions belonged to 4 populations from Iran was studied using eight primer combinations. A total of 221 scorable bands were amplified, of which, 118 (54.13%) were polymorphic. Resolving power (Rp) ranged from 5.70 to 9.21, and the average of polymorphism information content (PIC) per primer pair was 0.40. According to Nei's gene diversity and allelic statistics, Isfahan population had a highest genetic diversity (H = 0.3646, I = 0.5327, N_e = 1.6467). Coefficient of gene differentiation between populations (GST) was 0.124, indicated that mainly proportion of genetic variation (87.6%), was within populations and the remaining (12.4%) of the variation was among populations that, also supported by analysis of molecular variance (AMOVA). The gene flow (Nm) varied from 0.969 to 10.404 between pair-wise populations and was 3.504 among all of the populations. The Jaccard similarity coefficient between individuals ranged from 0.26 to 0.88. The UPGMA dendrogram clustered all 67 accessions into 6 groups. In some cases accessions from same region were grouped together but in most cases, there was gene exchange. To study the genetic relationships among populations, a principal coordinate analysis (PCoA) based on Nei's genetic distances was performed. Results of this study showed that AFLP marker can be a useful tool for investigating the genetic diversity of pomegranate genotypes.     

Biofertilizers improve plant growth,fruit yield,nutrition, metabolism and rhizosphere enzyme activities of Pomegranate (Punica granatum L.) in Indian Thar Desert

Production of horticultural crops has undergone enormous change in recent years due to development of innovative technologies including integrated nutrient management practices using biofertilizers. The present study represents the positive response of biofertilizers in nursery seedlings followed by their transplantation in harsh field conditions of Indian Thar Desert. Nursery and field experiments were carried out to assess the effectiveness of selected N₂-fixing bacteria and AM fungi alone or in combination, on the growth and biomass production of Punica granatum. In both experiments, the combined treatment of Azotobacter chroococcum and Glomus mosseae was found to be the most effective. Besides enhancing the rhizosphere microbial activity and concentration of various metabolites and nutrients, these bioinoculants helped in better establishment of pomegranate plants under field conditions. A significant improvement in the plant height, plant canopy, pruned material and fruit yield was evident in 5-year-old pomegranate plants in field conditions. In view of the above results, use of biofertilizer technology may be adopted for the establishment and development of other horticultural plant species in arid regions.     

Managing faba bean residues to enhance the fruit quality of the melon (Cucumis melo L.) crop

Mulching and/or topsoil incorporation of plant residues from green manure legumes can increase cropping system sustainability, and can supply and retain nutrients. Two field experiments were conducted in Italy over the period of 2006–2007, to investigate the effect of faba bean grown in a temperate environment to fruit morphology, quality and chemical composition of the subsequent melon (Cucumis melo L.) crop. Flowering faba bean plants were managed as mulch on the melon plant rows and cut and incorporated into the soil, in comparison with cultivated soil (control) and black plastic mulch.     

Characterization of progenies derived from pollination of pomegranate cv. Malase-Tourshe-Saveh using fruit traits and RAPD molecular marker

Fruit traits and molecular markers (RAPD) were used to survey genetic similarities and inheritance pattern of offspring, derived from self- and open pollination of pomegranate cv. Malase-Tourshe-Saveh (MTS) as well as progenies derived from cross between ‘MTS’ and ‘Narm-Daneh’ (ND) a soft-seed cultivar in the present study. Clustering based on fruit traits, divided the accessions firstly into two major groups, sweets and sour or sweet–sours. Members of sub-clusters were different in fruit characters, and seed softness also was affecting the grouping of individuals. Offspring of ‘MTS’ × ’ND’ showed somehow seed softness with varying degrees compared to other individuals. In RAPD analysis, by using 26 polymorphic primers, 325 fragments were produced from 39 individuals, among which 70 reproducible, polymorphic bands were scored for data analysis. NTsys and Bootstrap software were used for RAPD data analysis and respective dendrogram depicted by Jaccard's similarity coefficients using UPGMA method. The similarity coefficients were ranging from 0.2 to 0.94 and the lowest was obtained between pollen parent (ND cv.) and a genotype from open pollination of MTS cultivar. The highest similarity coefficient (0.94) was observed between two offspring both from self-pollination of MTS cultivar. In corresponding dendrogram, pollen parent was separated from other genotypes and laid individually in a sub-cluster, while the mother plant clustered with its progenies. In addition, some marker–trait associations were observed, especially for seed softness.     

Effect of synthetic auxins on fruit development of ‘Bing’ cherry (Prunus avium L.)

The main cherry cultivar grown in the warm climate of Israel, ‘Bing’, produces relatively small fruit. Over three consecutive years (2003–2005), application of 50 mg l⁻¹ 2,4-dichlorophenoxypropionic acid [2,4-DP; as its butoxyethyl ester (Power™)], 10 mg l⁻¹ 3,5,6-trichloro-2-pyridyloxyacetic acid [3,5,6-TPA; as the free acid (Maxim^®)], or 25 mg l⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) plus 30 mg l⁻¹ naphthaleneacetic acid (NAA; 0.3% Amigo™), at the beginning of pit-hardening when fruitlet diameter was ca. 13 mm caused appreciable and significant increases in fruit size and total yield, except when the crop load was heavy. Anatomical studies revealed that the main effect of these synthetic auxins was via direct stimulation of fruit cell enlargement. The above auxins had no negative effect on fruit quality, either at harvest or after 1 month of storage at 0 °C, or on return yield in the following year.     

Analysis of highbush blueberry (Vaccinium corymbosum L.) fruit growth with exponential mixed models

Blueberry fruit growth commonly exhibits a double-sigmoid pattern. The goal of this work was to characterize and compare fruit growth of cultivars differing in ripening time using exponential non-linear mixed models. Mixed-effects five-parameter exponential (Gompertz I and II; logistic; monomolecular) models were fitted to fruit diameter data from 2 years and three cultivars grown in the field in a cool temperate environment. Gompertz II mixed model provided the best fit to fruit growth data and was used for further analysis. In later ripening cultivars ‘Cape Fear’ and ‘Herbert’, clear-cut double-sigmoid patterns were observed, absolute growth rate models exhibited two marked peaks, and relative growth rate showed an initial decreasing trend, and a subsequent peak. The earlier cv. ‘O’Neal’ did not exhibit a defined double-sigmoid pattern. The time between relative extremes of absolute growth acceleration is proposed as an objective criterion for fixing stage boundaries within growth curves. Exponential mixed models accurately fitted blueberry growth patterns. These equations highlighted differences in fruit growth patterns between early and late ripening highbush blueberry cultivars.     

The inheritance of two novel subgynoecious genes in cucumber (Cucumis sativus L.)

Cucumber (Cucumis sativus L.), which is a vegetable crop, has served as the model system for sex expression in flowering plants, and the inheritance of sex expression in cucumber is well documented. However, the genetics of subgynoecism expression in cucumber had rarely been described. In this study, we investigated the inheritance of subgynoecious traits in cucumber plants with the inbred cucumber lines of subgynoecious (C. sativus L. var sativus cv 97-17 and S-2-98) as the materials. Genetic analysis had showed the two subgynoecious inbred lines were controlled by one pair of recessive gene and one pair of incompletely dominant gene, which were designated presently as mod-F2 and Mod-F1, respectively. Furthermore, the mod-F2 and Mod-F1 loci, which enhance the intensity of femaleness, also inherited independently with F and M genes.     

Phenotypic variability and genetic structure in plum (Prunus domestica L.), cherry plum (P. cerasifera Ehrh.) and sloe (P. spinosa L.)

In the present study, phenotypic variability of 80 plum (Prunus domestica L.) varieties maintained in the French National Plum Collection was evaluated with 19 quantitative traits. In addition, genetic diversity and genetic structure was studied in three plum species (P. domestica L., Prunus cerasifera Ehrh. and Prunus spinosa L.) using chloroplast DNA (cpDNA) markers and five single sequence repeat (SSR) loci. Based on phenotypic traits, some varieties, such as mirabelle plums, grouped together. Bayesian structure analysis was used to identify different genetic groups, whereby damson plums were clearly distinguished from greengage plums. When examining the three species together, a higher level of cpDNA allelic richness was found in P. cerasifera and in P. spinosa than in P. domestica where only five cpDNA haplotypes were detected in the national plum collection, with one main haplotype that accounted for 80% of the varieties studied. P. domestica cpDNA haplotypes tended to group together with P. cerasifera haplotypes whereas most of P. spinosa haplotypes formed a separate cluster. SSR markers were somewhat able to distinguish the three species. These results provide some clues as to the origin of plum and the various plum varieties. Our results also provide useful information for the management of plum genetic resources.     

Effect of pollination intensity,frequency and pollen source on fig (Ficus carica L.) productivity and fruit quality

Yield and fruit quality in fig (Ficus carica L.) are highly dependent on cultural practices especially caprification (pollination). However, this technique remains not well controlled in Tunisia. This study was conducted during two successive years, 2009 and 2010, to investigate different pollination conditions, i.e. number of caprifigs and repetitions of caprification on fruiting of two cultivars Bouhouli (San Pedro type) and Zidi (Smyrna type). In addition, the efficiency of four pollen sources was evaluated to identify the most effective pollinator for female cultivar Zidi. The following parameters were recorded: fruit number per shoot, fruit set, productivity, fruit characteristics and vegetative growth.     

Effects of cultural cycles and nutrient solutions on plant growth,yield and fruit quality of alpine strawberry (Fragaria vesca L.) grown in hydroponics

Alpine strawberry (Fragaria vesca L.) was grown in hydroponics with the nutrient film technique, in order to evaluate the effects of four buffer concentrations (1.3, 1.6, 1.9, 2.2 mS cm⁻¹) and two cultural cycles (summer-spring versus autumn-spring) in terms of growth, yield and fruit quality (dry and optical residues, sugars, acids, antioxidants, mineral composition). The longer summer-spring cycle gave a correspondingly higher yield than the autumn-spring one. The 1.3 mS cm⁻¹ nutrient solution was the most effective in terms of overall and spring production. However, the autumn and winter yields were not affected by the buffer EC. Fruit quality did not change with the cultural cycle, but the berries harvested in the spring had higher vitamin C and sucrose content and lower nitrate content compared with berries picked up in the winter. Fruit quality was also improved when the nutrient solution concentration increased. From the productive point of view, the cultural cycle choice should be made considering that 71% of the yield of the more productive summer-spring cycle derived from the spring harvest. Moreover, as regards the nutrient solution strength, 1.3 mS cm⁻¹ EC should be preferred during the spring season, whereas the 2.2 mS cm⁻¹ EC proved to be best in the winter in terms of fruit quality.     

Foliar application of chlorocholine chloride improves leaf mineral nutrition,antioxidant enzyme activity,and tuber yield of potato (Solanum tuberosum L.)

In southern China, potatoes (Solanum tuberosum L.) are grown in the late season and the crops are often subjected to low temperature stress particularly during the tuber bulking stage. Exogenous chlorocholine chloride (CCC) treatment has been found to improve crop performance under suboptimal growth conditions; however, the physiological mechanisms underlying the beneficial effects have not been fully understood. The objective of this study was to investigate the effects of CCC treatment on mineral nutrition, antioxidant enzyme system, and tuber yield of potato (cv. Zhongshu 3) under field conditions. The plants were foliar sprayed twice with 1.5, 2.0 and 2.5 g l⁻¹ CCC at 24 and 28 days after emergence (DAE), respectively; and plants without CCC treatment were serviced as control. Leaf samples were collected on 56 DAE for determination of mineral nutrition contents and antioxidant enzyme activity. Results showed that 1.5 and 2.0 g l⁻¹ CCC treatments significantly increased the contents of P, K, Ca, Mg, Fe, Mn, Zn and Cu in potato leaves. These treatments also increased superoxide dismutase (SOD), peroxidases (POD) and catalase (CAT) activities in the leaves. A positive linear relationship was found between SOD activity and the content of Fe + Mn + Zn + Cu. Tuber yield was significantly increased by CCC treatment. It is concluded that treatment with certain concentration of CCC (e.g. 1.5–2.0 g l⁻¹) improves mineral nutrition and SOD, POD and CAT activities in potato leaves; which might have contributed to the higher tuber yield of the crop grown under suboptimal conditions.     

Regional and maturational effects on essential oils yields and composition of coriander (Coriandrum sativum L.) fruits

The composition of volatile components of the essential oils extracted from fruits of coriander (Coriandrum sativum L.) growing in two different Tunisian regions in both Menzel Temime and Borj El Ifaa was studied by GC and GC–MS. The highest oil yields were observed at final stages of maturity: 0.324 ± 0.09% and 0.327 ± 0.08%, in Menzel Temime and Borj El Ifaa, respectively. Essential oil yields were highly (P < 0.001) affected by the growing region, stages of maturity and their interaction. Essential oil composition changed significantly (P < 0.05) among the different stages of maturity and growing region. Linalool and geranyl acetate were the main compounds at full fruit maturity in the two studied regions. Growing region, stages of maturity and their interaction had a strong effect (P < 0.001) on 35 compounds. α-Pinene, sabinene, limonene, γ-terpinene, cis-dihydrocarvone and geranial were insensible to the regional factor.