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- Author or Editor: Francesco Saccardo x
A research project was conducted at the University of Tuscia, Viterbo (central Italy), to set up a vegetative propagation system for producing diseasefree artichoke transplants (Cynara cardunculus var. scolymus) of the Romanesco type (cultivar C3). The system included the following steps: 1) micropropagated plantlets were grown in a soilless culture year-round in greenhouse conditions, starting at the end of August; 2) stock plants were periodically treated with a chemical growth regulator [6-benzylamino purine (BA)] and then cut back at the collar level to promote offshoot production; 3) offshoots were periodically harvested and cold stored; and 4) cuttings were rooted at the end of spring under conditions of high humidity in multi-pack trays so as to be ready for summer transplanting. Results showed that the foliar application of BA to the stock plants increased the offshoot number quadratically to 200 mg·L-1. The rooting percentages of cuttings and root growth were enhanced by raising the cutting weight class (30-45 g) and by the application of naphthaleneacetic acid (NAA) to the cutting root zone at a rate of 2000 mg·L-1. The percent rotten cuttings increased as the 2 °C cold-storage time increased from 30 to 150 days. Similarly, the percentage of rooting and root growth decreased approximately from 60 to 150 days.
Research was conducted at the University of Tuscia (central Italy) to validate the propagation system for globe artichoke (Cynara cardunculus var. scolymus) described in a previous paper for a 1-year production cycle. The resulting globe artichoke plants were used in a 2-year field trial to investigate the field response of plantlets obtained with our propagation technique in comparison with plantlets produced by in vitro propagation and by offshoots harvested in commercial fields. The total number of artichoke plantlets obtained with our propagation system was 62.7 plantlets/m2 per year. In the first year, the globe artichoke production (bud number and fresh bud weight) was higher in plants obtained with our propagation system and by micropropagation than in those obtained from offshoots harvested in commercial fields. The production cost of plantlets obtained with our propagation technique was 52% lower than those of the micropropagated plantlets. This could lead to a significant reduction of production costs for artichoke growers, while preserving the advantages of in vitro propagation (disease-free plants and plant uniformity).
Grafting represents an effective tool for controlling the race 1,2 of Fusarium oxysporum f. sp. melonis (FOM) and Didymella bryoniae in melon (Cucumis melo L.). Although not considered a soilborne pathogen, D. bryoniae survives on plant remains in the soil. The lack of effective resistant commercial hybrids and the gradual reduced use of soil fumigation with methyl bromide increase the risk of damages by both these pathogens. We determined the effectiveness of eight commercial rootstocks, ‘RS 841’, ‘P 360’, ‘ES 99-13’, ‘Elsi’ (Cucurbita maxima Duchesne × Cucurbita moschata Duchesne), and ‘Belimo’, ‘Energia’, ‘Griffin’, ‘ES liscio’ (Cucumis melo genotypes), for their resistance to FOM and D. bryoniae. During 2003 and 2004 growing seasons, the inodorus F1 hybrid Incas was grafted onto each of these commercial rootstocks and then evaluated, under greenhouse conditions, in terms of productivity and fruit quality. Cucurbita rootstocks (‘RS 841’, ‘P 360’, ‘ES 99-13’, ‘Elsi’) were highly resistant both to the race 1,2 of FOM (100% survival) and to D. bryoniae (almost absent crown lesions and low leaf disease index); this reaction clearly differed from that of both the C. melo rootstocks (‘Belimo’, ‘Energia’, ‘Griffin’, ‘ES liscio’) and the control Incas. In both years, the highest yield was recorded in the graft combination Incas/‘RS 841’ with 5.6 and 8.1 kg·m−2 during 2003 and 2004, respectively. The Cucurbita rootstock ‘RS 841’ produced yields higher than C. melo rootstocks (‘Belimo’, ‘Energia’, ‘Griffin’, ‘ES liscio’) and the control Incas. Fruit dry matter, titratable acidity, total soluble solid contents, fruit firmness, and Hunter color [L* (brightness), a* (redness), and b* (yellowness) parameters] of grafted melons were similar to those of the plants grown on their own roots.
A greenhouse experiment was carried out to determine the effect of cationic proportions (K, Ca, Mg) in the nutrient solution on carotenoids and α-tocopherol content at green–orange, orange, red, and intense-red ripening stages using a high-pigment tomato (Lycopersicon esculentum Mill.) cultivar hp (`Lunarossa') and a standard cultivar (`Corfù') grown in a soilless culture. The highest lycopene concentration was observed in the `hp' cultivar at the red and intense-red ripening stages (3.0 mg/100 g fresh weight and 3.2 mg/100 g fresh weight respectively). In both cultivars, the concentration of β-carotene increased during the ripening stages, reaching the highest value (0.6 mg/100 g fresh weight) at the intense-red stage. The hp cultivar has guaranteed higher lycopene (average, 2.0 mg/100 g fresh weight vs. 1.7 mg/100 g fresh weight) and α-tocopherol contents (average, 1.2 mg/100 g fresh weight vs. 0.9 mg/100 g fresh weight) than those of the standard. In both cultivars, a high proportion of K in the nutrient solution increased antioxidant concentration β-carotene and especially lycopene) during the red and intense-red ripening stages, followed by Mg. The lowest values were recorded for the Ca treatment. Lastly, a positive correlation was recorded between fruit tissue K and lycopene content, whereas a negative correlation was observed between fruit tissue Ca and lycopene content.