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.     

Application of treated wastewater for cultivation of roses (Rosa hybrida) in soil-less culture

No information is available today concerning the effect of irrigation with secondary treated sewage water on growth, production or quality of roses or other cut flowers. In the present study we investigated the effect of irrigation with treated sewage water on roses cultivated in two soil-less medium, perlite, an inert mineral medium and Choir (coconut fibers), an organic medium of high ion absorption capacity. During 12 months of exposure to the treated water, the visible appearance of the plants, their growth, the quantity and size of the flowering stems and their postharvest performance were not affected by the irrigation treatments. Contents of macroelements in the leaf tissues were unaffected by the irrigation with the secondary treated sewage water. At the same time, Cl contents increased 47% in perlite and 73% in Choir grown plants reaching levels characteristic of exposure to moderate salinity. Mn, Cu and B contents increased as well under cultivation in both perlite and Choir under irrigation with treated sewage water. On the other hand, contents of Fe, Zn, Mo and Al, were similar in all treatments. In all treatments contents of all the examined micro and macroelements were within the range accepted for proper plant function.     

Phytochemical and antioxidant properties of selected fig (Ficus carica L.) accessions from the eastern Mediterranean region of Turkey

Fig has been a typical fruit component of the health-promoting Mediterranean diet for a very long time. Phytochemical characters and antioxidant capacity of green-, yellow-, brown-, purple-, and black-fruited fig (Ficus carica L.) accessions were investigated. In this study, total phenolics (TP), total anthocyanins (TA), fructose (FRUC), glucose (GLUC), sucrose (SUC), and variables (such as L*, a*, C*, and hue°) describing fruit skin colors were examined. Also, the antioxidant capacity (TAC) of fig fruits was determined by the ferric reducing antioxidant power (FRAP) assay. Antioxidant capacity was significantly correlated with the polyphenol and anthocyanin (r = 0.74 and 0.63, respectively) contents of fruits. Black fig accessions had the highest TAC (range of 7.9–16.1, mean 12.4 Fe²⁺ mmol/kg FW), TA (range of 32.3–356.0, mean 128.4 μg cy-3-rutinoside/g FW), and TP content (range of 69.1–220.0, mean 118.9 mg GAE/100 g FW). These black-fruited accessions had 2-fold greater TAC, 15-fold greater TA, and 2.5-fold greater TP than green and yellow fig accessions. However, the FRUC, GLUC, and SUC content of brown and purple fig accessions were higher than those of other color groups. The predominant sugars present were fructose (∼56%) and glucose (∼43%), as determined by HPLC.     

Sequence analysis of the internal transcribed spacers (ITSs) region of the nuclear ribosomal DNA (nrDNA) in fig cultivars (Ficus carica L.)

Sequences of the internal transcribed spacers (ITSs) of nuclear ribosomal DNA (nrDNA) were analysed in a set of Tunisian fig (Ficus carica L.) cultivars. The size of the spacers sequences ranged from 200 to 279 bases for ITS1 and from 253 to 314 bases for ITS2. Variation of GC contents has been also observed and scored as 59–68% and 55–68% for ITS1 and ITS2, respectively. This data exhibited the presence of polymorphism among cultivars. The intra-specific variability level of the ITS sequences proved a variation both in the length and in the sequences studied. In fact, ITS1 and ITS2 sequences were considered as a useful tool to establish genetic relationships among cultivars. Our results indicate that the diversity detected among closely related genotypes supported strongly the efficiency of ITS sequences for establishing relationships between cultivars. ITS2 seems to be relatively more informative than ITS1 regarding length or GC contents. Considerable genetic diversity was observed among fig at intra and inter-cultivars levels. Two polyclonal varieties were identified. In addition, data proved that a typically continuous genetic diversity characterizes the local fig germplasm. The topology of the derived dendrogram strongly supported this assumption. In fact, genotypes are clustered independently from their geographical origin or the sex of trees suggesting a narrow genetic basis among the ecotypes studied in spite of their phenotypic distinctiveness. Implications of these results for management of fig germplasm collections are discussed.     

Genetic analysis of Tunisian fig (Ficus carica L.) cultivars using amplified fragment length polymorphism (AFLP) markers

Genetic diversity of forty fig cultivars collected from five regions in Tunisia was investigated using amplified fragment length polymorphism (AFLP). A total of 342 reproducible bands amplified with six AFLP primer combinations were obtained. The high percentage of polymorphic bands (%PB) of 97.5 and the resolving power (Rp) collective rate value of 143 were scored. In addition, the polymorphism information content (PIC) values varied from 0.61 to 0.87 with an average of 0.77. Although cluster (UPGMA) and principal components analyses indicate that the cultivars’ clustering made independently both from the geographical origin, horticultural classifications and/or from the sex of trees. In addition, the observed variation suggests considerable differentiation among fig cultivars. The present data supports the common origin of the fig cultivars. Analysis of molecular variance (AMOVA) revealed that average Φ_ST value overall loci was 0.026, and the overall distribution pattern of molecular variation indicated that about 97.43% of the total variance was accounted by the within-region variance component. The remaining 2.5% (P < 0.001) of the variation was founded among cultivars of the prospected regions. Our results proved that AFLP markers are useful for germplasm discrimination as well as for investigation of fig patterns variation. The information may be useful to define conservation management program.     

Fruit characteristics of fig cultivars and genotypes grown in Turkey

In this study, fruit quality characteristics of some cultivars and types of fig (Ficus carica L.) were determined in Dortyol, Hatay, Turkey, which has a Mediterranean climate. The main fig cultivars grown in Turkey (‘Sarilop’, ‘Bursa Siyahi’, ‘Goklop’, ‘Yediveren’, ‘Yesilguz’, ‘Morguz’, ‘Sari Zeybek’, and ‘Ufak Yesil’) were evaluated along with 24 selections from a larger collection from the Mediterranean Region of Turkey. Several pomological characteristics of the genotypes were determined on 5-year-old trees during the 2001 and 2002 growing season. Averaged over the 2 years, fruit weight ranged between 22 and 52 g, total soluble solids content (TSS) ranged between 20.1 and 27.4%, and acidity ranged between 0.09 and 0.26%. ‘Bursa Siyahi’, ‘Goklop’, 31-IN-17, 31-IN-11 and 31-IN-09 produced the largest fruits in terms of fruit weight and dimensions. 31-IN-01, 31-IN-02, ‘Yesilguz’, ‘Morguz’ and ‘Ufak Yesil’ had the highest TSS. ‘Yediveren’, ‘Goklop’, ‘Bursa Siyahi’ and 31-IN-16 scored the highest in overall quality according to the weighted ranked method. Based on the results obtained ‘Yediveren’, ‘Goklop’ and 31-IN-16 could be alternatives to ‘Bursa Siyahi’, currently the most favored fresh table fig cultivar. These alternatives appear to have potential for both local consumption and export markets. Our results also indicate extensive diversity among Turkish figs permitting marketing of a broad range of fresh fig traits.     

Effects of different nutrient solution formulations on morphological and biochemical characteristics of nursery fig trees grown in substrate culture

This research was carried out to determine the effects of different nutrient solution formulations on the growth of nursery fig trees in substrate culture, which is one of the soil-less culture techniques. The hardwood cuttings of Ficus carica L. cv. “Sar?lop” (Calimyrna) were planted into pots filled with 13 L of perlite. Five different nutrient solution formulations were tested on the quality and growth progress of nursery fig trees. The trials were conducted in two different growing conditions, namely, high-tunnel and open-field conditions in substrate culture. To observe the effect of different nutrient solution formulations on nursery fig trees, some morphological and biochemical characteristics were determined. It was concluded that the use of Hewitt's and Hoagland's nutrient solution formulations led to increased growth of nursery fig trees in high-tunnel and open-field conditions, respectively.     

Effect of hydrogen cyanamide,mineral oil and thidiazuron in combination with tip pruning on bud break,shoot growth and yield in ‘Bourjasotte Noire’, ‘Col de Damme Noire’ and ‘Noire de Caromb’ figs

Commercial fig production is relatively new to the Mediterranean-type climate Western Cape Province of South Africa. A lack of lateral branch development impedes tree structure development and therefore adequate yields of quality fruit. The chemical rest breaking agents, Lift^® (thidiazuron 3 g L⁻¹) at 6%, Dormex^® (hydrogen cyanamide, 520 g L⁻¹) at 4%, mineral oil at 4% and a combination of mineral oil and Dormex^® at 2% each were evaluated in a split plot design in combination with tip-pruning vs. no-pruning to overcome apical dominance and increase complexity (Experiment 1). During the 2008/2009 season, an additional investigation was conducted to evaluate the use of thidiazuron and hydrogen cyanamide for harvest scheduling (Experiment 2). Dormex^® at 3% and Lift^® at 6%, were applied to dormant trees on 30 June 2008, 3 August 2008, 15 August 2008 or 30 August 2008. In general, Lift^® can be used to increase the number of buds breaking in ‘Bourjasotte Noire’ and ‘Col de Damme Noire’, while tip pruning decreased bud break with a resultant increase in shoot length. Dormex^® and oil combined decreased bud break in these two cultivars but was effective on ‘Noire de Caromb’. Where bud break was increased the resultant N + 1 shoot length was decreased. RBAs increased the number of fruit in both the breba and main crop of ‘Noire de Caromb’, but decreased fruit size of the breba crop. Our data are not conclusive as to what the reason for low lateral bud break might be but leans towards strong AD in seasons with 400 Utah CU or more, but might include some delayed foliation response in seasons with less than 200 Utah CH.     

Production of inter-section hybrids between Primula filchnerae and P. sinensis through ovule culture

Inter-section hybrids were obtained in the reciprocal crosses between Primula filchnerae (2n = 2x = 24) of Sect. Pinnatae and P. sinensis ‘Fanfare’ (2n = 2x = 24) of Sect. Auganthus by rescuing ovules on half-strength (1/2) Murashige and Skoog's (MS) medium supplemented with 50 g l⁻¹ sucrose, 2.5 g l⁻¹ gellan gum, 0.1 mg l⁻¹ α-naphthaleneacetic acid (NAA), 0.1 mg l⁻¹ 6-benzyladenine (BA) and 50 mg l⁻¹ gibberellic acid (GA₃). In ovule culture, germination occurred with radicle elongation but no plumule was observed. The radicle kept on the initial medium showed root proliferation with callus formation. When the calluses were transferred to (1/2)MS media containing 30 g l⁻¹ sucrose and 3 g l⁻¹ gellan gum, without plant growth regulators (PGRs) or with 1 mg l⁻¹ zeatin and 0.1 mg l⁻¹ NAA, plantlets were regenerated. The plants thus obtained were confirmed to be hybrids through flow cytometry (FCM) and random amplified polymorphic DNA (RAPD) analyses. The hybrid obtained when P. filchnerae was used as the maternal parent was diploid, whereas hexaploid hybrid was obtained when using P. sinensis as the maternal parent. The hexaploid hybrid might be produced through chromosome doubling of a triploid originated from the fertilization of P. sinensis with unreduced pollen of P. filchnerae.     

The culture of isolated microspores of ornamental kale (Brassica oleracea var. acephala) and the importance of genotype to embryo regeneration

The culture of isolated microspores of kale (Brassica oleracea var. acephala) was studied including the importance of genotype to embryo regeneration, medium composition chiefly the sucrose concentration and the use of colchicine, simultaneously medium renovation. It was initiated using 29 different genotypes as donor plants. Embryos were induced from six of the kale genotypes and these corresponded to the more out-bred genotypes. Embryogenesis was achieved using four different combinations of culture media: (a) microspores initially cultured in NLN medium supplemented with 13% (w/v) sucrose (NLN-13) for 48 h, followed by transfer to fresh NLN-13 medium; (b) microspores cultured for 48 h in NLN-13 medium supplemented with colchicines (50 mg/L) followed by transfer to unsupplemented NLN-13 medium; (c) microspores cultured for 48 h in NLN-16 medium supplemented with colchicines (50 mg/L) followed by transfer to unsupplemented NLN-16 medium; (d) microspores cultured for 48 h in NLN-16 medium supplemented with colchicines (50 mg/L) followed by transfer to unsupplemented NLN-13 medium. The embryos obtained from four of the genotypes developed into plantlets and these regenerated plants have been successfully transplanted to soil.     

Micropropagation of the Brazilian endemic bromeliad Vriesea reitzii trough nodule clusters culture

Vriesea reitzii Leme & Costa is an endemic bromeliad from the Atlantic Forest in South Brazil. The devastation of this biome threatens the extinction of this species that besides its role in the ecosystem has an ornamental value. Tissue culture techniques are important tools for the mass propagation of threatened bromeliad species. In the present work we established an in vitro regenerative protocol for the large-scale propagation, and improvement of this species. Young basal leaves used as explants showed 90.6% induction rate of nodule clusters in MS culture medium supplemented with 20.0 μM 2,4-D and 1.0 μM Kin. The subculture of these nodule clusters to MS medium with BAP, Kin and 2-iP resulted in a regeneration rate of 60 shoots/g nodule clusters. Subsequent subculture to MS media supplemented with 2.5 μM 2-iP and 0.5 μM NAA and then to MS medium free of PGR enhanced the full development of plantlets. Plantlets longer than 3 cm were successfully acclimatized showing a survival rate of 90%.     

Molecular polymorphism of cytoplasmic DNA in Ficus carica L.: Insights from non-coding regions of chloroplast DNA

The trnL (UAA) intron and the intergenic spacer between the 3′ exon of trnL (UAA) and trnF (GAA) sequences were used as genetic markers for differentiating Ficus carica cultivars and establishing refined genetic relationships. The study was based on 20 fig cultivars, collected from south and centre of Tunisia. Since, the intron was thought to be more variable among close relatives than is the chloroplast spacer. The size of these non-coding regions varied from 554 to 589 and from 989 to 1022 bases pairs for the intron and the combined sequences correspondingly. The average of GC content was 33.9% and 34.6% in the intron and the combined intron and spacer respectively. High values of A + T contents were detected in both data sets and may explain the high proportions of transversions founded. The observed variation pattern of plastid DNA provides evidence of an important genetic diversity. The overall transition/transversion bias (R) was 0.202 in the intron and 0.27 in the combined regions. The RI index of 0.592 indicates that these combined sequences have clearly more homoplasy then the intron (RI = 0.705) and spacer (RI = 0.777) sequences separately. Phylogenetic trees were generated based on maximum parsimony (MP) and neighbor-joining (NJ) analysis of the chloroplast sequences data. Results proved that a typically continuous genetic diversity characterizes the local fig germplasm. In fact, relationships inferred from the cpDNA analysis suggest several clades, which do not show geographical or tree sex correspondence. Although the level of apparent diversity is considerable, we may conclude that non-coding regions of chloroplast genome provide a new and practical opportunity to evaluate genetic diversity and to discriminate fig cultivars. Revealed cytoplasmic DNA markers are reliable to elaborate a molecular data base to conduct management and breeding programs on local fig germplasm.     

Molecular based assessment of genetic diversity within Barbary fig (Opuntia ficus indica (L.) Mill.) in Tunisia

In this work, we report for the first time on the analysis of genetic diversity within a set of 36 Tunisian Opuntia ficus indica (L.) Mill. ecotypes using RAPD markers.     

Pollination with laser-irradiated pollens breaks cross-incompatibility between zicaitai (Brassica campestris var. purpurea) and ornamental kale (Brassica oleracea var. acephala) to produce hybrids with the aid of ovule culture

The objective of this study was to produce interspecific hybrids between an Ogura-cytoplasmic male sterile (CMS) line of zicaitai (Brassica campestris var. purupurea, 2n = 20) and cultivars of ornamental kale (Brassica oleracea var. acephala, 2n = 18) to develop a CMS system for hybrid seed production. Pollination with pollen grains of ornamental kales irradiated at a power output of 9.0 mW with a He–Ne laser for 3 min could overcome the cross-incompatibility between the species concerned. Intact hybrids could be efficiently produced from ovules cultured on Murashige and Skoog media supplemented by 0.2 mg l⁻¹ 6-benzyladenine. Chromosome number of hybrids was confirmed to be 2n = 19. Hybrids resembled ornamental kales in leaf morphology and in vernalization response. Pollens of hybrids had a sterile appearance. Moreover the hybridity of the putative hybrids was confirmed by RAPD data on a DNA fragment of 820 bp.     

Regeneration and characterization of plants derived from leaf in vitro culture of two sweet orange (Citrus sinensis (L.) Osbeck) cultivars

In the current work attempts were made to investigate culture of leaf explants derived from in vitro seedlings of two sweet orange (Citrus sinensis (L.) Osbeck) cultivars, Bingtangcheng and Valencia. Effects of several factors, including culture medium, lighting condition, explant age and genotype on regeneration response were examined based on three parameters, percentage of explants producing shoots, mean number of shoots per explant and shoot forming capacity. Culture of the explants on shoot-inducing media (SIM) composed of MT salts supplemented with different growth regulators gave rise to disparate shoot regeneration, in which SIM₁ (MT + 0.5 mg L⁻¹ BA + 0.5 mg L⁻¹ Kinetin + 0.1 mg L⁻¹ NAA + 3% sucrose + 0.8% agar, pH 5.8) was shown to be the most effective medium for direct induction of shoots from leaf explants. Highly significant difference in the response of shoot bud regeneration was noted between the two cultivars, with Bingtangcheng being more responsive than Valencia. Culture of explants from fully developed leaves led to better shoot regeneration capacity in comparison to undeveloped ones. However, the two lighting conditions used herein did not cause significant difference in shoot regeneration. Phenotypic observation and randomly amplified polymorphic DNA (RAPD) analysis confirmed that all the regenerated plants from both genotypes were genetically identical to their donor plants, suggesting absence of detectable genetic variation in the regenerated plants. The data presented here demonstrated that direct initiation of plants from leaf explants has been successfully accomplished. To our knowledge, this is the first report on direct regeneration of shoots from leaf explants in Citrus, which will provide an alternative source for citrus genetic manipulation in the future.     

The use of green waste compost in peat-based potting mixtures: Fertilization and suppressiveness against soilborne diseases

Twelve commercially produced Dutch green waste composts were evaluated for their suitability to replace 20% (v/v) peat substrate in the cultivation of ornamentals. Salt concentrations were determined in water extracts of the composts and disease suppressive effects were assessed against various soilborne diseases. The Cl-concentration of the compost extract appeared to be the limiting factor for use of the composts in potting mixtures. The Cl-concentrations in 7 and 1 composts, respectively, were too high to replace 20% of peat for growing salt sensitive and moderately salt sensitive plants, according to guidelines set for these groups of plants. The suppressive effects of the composts were tested in peat-based potting mixtures using three bioassays: Phytophthora cinnamomi—lupin, Cylindrocladium spathiphylli—Spathiphyllum and Rhizoctonia solani AG2-1—cauliflower. Disease levels in compost-amended mixtures were compared with the non-amended controls. None of the composts induced suppressiveness against P. cinnamomi; 3 and 9 composts significantly induced suppressiveness against C. spathiphylli and R. solani, respectively. No significant disease enhancement was observed in any of the bioassays. The pH of the potting mixture showed a negative correlation with suppression of the Rhizoctonia disease (R² = 0.56). The effect of pH (pH 4–6) on suppression of R. solani and P. cinnamomi was further studied in non-amended peat. Disease suppression of R. solani in cauliflower decreased with increasing pH in two different kinds of peat, while there was no effect on P. cinnamomi. The suppressive effect of 3 composts was assessed in two experiments against Fusarium wilt in Cyclamen persicum (caused by F. oxysporum f. sp. cyclamini) and Begonia eliator (caused by F. foetens) under near-commercial conditions. None of the composts had a significant effect on Fusarium wilt in Cyclamen. Two and 3 composts significantly induced suppressiveness against Fusarium wilt in Begonia in the first and second experiments, respectively. No significant differences were observed in growth characteristics between Begonia plants grown in compost-amended and non-amended potting mixture in both experiments. In the second experiment, Cyclamen plants grown in compost-amended potting mixture had significant lower number of flowers than plants grown in non-amended potting mixture, which may have been due to lower concentrations of N in the compost-amended potting mixtures. In conclusion, most composts of the origin and composition tested can replace 20% peat in potting mixtures for moderately salt sensitive and salt tolerant plants. Amendment of these composts can contribute to control of Fusarium wilt in Begonia plants.     

Effect of genotype,explant size,position, and culture medium on shoot generation of Gerbera jamesonii by receptacle transverse thin cell layer culture

An unique procedure for the mass shoot propagation of Gerbera using receptacle transverse thin cell layer (tTCL) culture procedure was developed. Genotype, flower bud age, explant size, position of receptacle tTCLs and culture media were found to affect the success of culture. Ten interspecific crosses of Gerbera showed different shoot regeneration rates and callus induction via receptacle tTCL culture, all of which had shoot regeneration rates higher than 57%. Flower buds collected on the 10th day resulted in 91% shoot regeneration after 6 weeks of culture on basal MS medium [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassay with tobacco tissue cultures. Physiol. Plant. 15, 475–497] supplemented with 0.02 mg l⁻¹ thidiazuron (TDZ), 0.8 mg l⁻¹ adenine and 10% (v/v) coconut water (CW). This was significantly higher than those from flower buds on the 7th and 14th days (22% and 54%), respectively. Shoot regeneration rate was the highest (94–100%) in the middle layers of the receptacle. For mass shoot propagation, shoot clusters were subcultured on half-strength MS medium supplemented with 0.5 mg l⁻¹ indole-3-butyric acid (IBA), 0.5 mg l⁻¹ 6-benzyladenine (BA) and 2.0 mg l⁻¹ kinetin after every 4 weeks. Plantlets formed when single shoots were cultured on half-strength MS medium containing 1 mg l⁻¹ IBA. All plantlets acclimatized well in the greenhouse.     

Seed inoculation with Azospirillum mitigates NaCl effects on lettuce

Data on the growth-promoting effects of Azospirillum on lettuce exposed to either normal or saline conditions, is scarce. Lactuca sativa L., cv Mantecosa seeds were colonized with A. brasilense Sp245 cells during imbibition. Germination percentages were determined after 7 d treatments with 0, 30, 50 or 80 mol m⁻³ NaCl. In another experiment, seeds germinated in Hoagland were irrigated for 30 d with 0, 30, 50 or 80 mol m⁻³ NaCl supplemented media. Vegetative growth proceeded in a growth chamber with a 13–11 h day–night cycle. Buffer-imbibed seeds were considered non-inoculated controls. Plant samples were taken at 0, 14, 20, and 30 d after the onset of NaCl treatments and dissected in aerial and root portions. The weights of both tissues were measured. Azospirillum-inoculated seeds had significantly higher germination percentages than controls in all treatments. Inoculated dried seeds stored up to 30 d maintained such characteristic in most of the treatments, particularly at 80 mol m⁻³ NaCl. Plants grown from inoculated seeds and irrigated with saline media displayed higher total fresh and dry weights and biomass partition to the aerial portion, than non-inoculated controls. Azospirillum-inoculated lettuce seeds had better germination and vegetative growth than non-inoculated controls after being exposed to NaCl.     

Somatic embryogenesis in pepper anther culture: The effect of incubation treatments and different media

The frequency of obtained androgenic plants depends highly on the genotype; therefore the low rate of haploid recovery limits the utility of anther culture in pepper breeding. The need for incubation treatment and adequate nutrition media supplemented with plant growth regulators, especially auxins, are suggested as important factors to obtain somatic haploid embryos in pepper anther culture. The effect of three incubation treatments of the androgenic potential in pepper anther culture on MS, N, LS, NN and CP medium are summarised, and the results demonstrate that:

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by incubating treatment in cold conditions (at 7 °C) in darkness for 7 days, and then transferring the explants to light conditions (12-h photoperiod at 25 °C) for 4 weeks, on LS and NN mediums, anthers produced callus;