Browsing by Author "Gambardella, Marina"

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    Control of shoot-tip necrosis during Argylia radiata in vitro multiplication
    (2022) Morales-Tapia, Pablo; Gambardella, Marina
    Argylia radiata is an herbaceous perennial plant native to northern Chile and a representative species of the "Blooming Desert". Due to its showy flowers and other morphological characteristics, A. radiata has great ornamental potential. In earlier work, a deep morpho-anatomical description was made, but the micropropagation protocols, which could be used for commercial purposes, are not known. Previous assays showed that cytokinin supplementation improves the multiplication rate but produces shoot-tip necrosis in the microplants. To avoid it, different modifications of the growth medium were tested, including calcium nitrate supplementation; increasing in agar concentration; indole-3-butyric acid enrichment; and change of the basal medium formulation. The effect of these changes over the damage level, number of shoots, multiplication rate, plant height (cm), fresh weight and dry weight (g), and water content (%) of the microplants were evaluated. The use of McCown Woody Plant formulation as basal medium showed the best effect, reducing the damage level and improving the multiplication rate. Additionally, IBA supplementation was effective in reducing necrotic damage. However, 0.1 mg L-1 of IBA significantly decreased the multiplication rate, while 0.01 mg L-1 led to a higher multiplication rate than that of plants grown in the control medium. In conclusion, the use of McCown Woody Plant medium and IBA supplementation should be considered in commercial A. radiata micropropagation.
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    Postharvest physiology and storage potential of new Chilean raspberry cultivars
    (2021) Contreras, Carolina; Hermosilla, Adolfo; Naranjo, Paulina; Pablo Zoffoli, Juan; Gambardella, Marina
    Raspberries (Rubus ideaus L.) are highly perishable and susceptible to rot during storage. An exploratory study of postharvest physiology associated with maturity was carried out for three new Chilean raspberry cultivars: Santa Catalina, Santa Clara and Santa Teresa. Fruit of these cultivars were harvested at three maturity stages based on color: pink (C3), bright red (commercial maturity) (C4) and dark red (C5). Two experiments were carried out to: i) determine postharvest quality and physiological parameters associated with maturity stages in comparison to those fruits of the main cv. Heritage, and ii) evaluate storage potential at 0 and 4 degrees C of 'Santa Catalina'. In the first study, fruit quality parameters (such as weight, firmness, color, among others) of all the 'Santa' cultivars were assessed immediately after harvest, and the ethylene production and respiration rates (CO2) were recorded for 4 d at 20 degrees C. In the second experiment, 'Santa Catalina' was stored at 0 and 4 degrees C. According to the results of the first experiment, 'Santa Teresa' presented the largest fruit (7.9 g), followed by 'Santa Clara' (5.3 g), 'Santa Catalina' (4.9 g) and 'Heritage' (3.3 g). 'Santa Clara' (similar to 6 ng kg(-1) s(-1)) fruits had the highest levels of ethylene production, followed by 'Santa Catalina', and 'Santa Teresa' with the lowest production. Regardless the cultivar, the fruit at the C5 stage always showed the highest ethylene production. Overall, compared with 'Heritage', these three new cultivars presented better fruit quality at harvest. The 0 degrees C was an adequate storage temperature for 'Santa Catalina' reaching storage potential of 20 d without soft fruits; therefore, it is recommended for fresh markets.
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    Standardization of an In Vitro Seed Germination Protocol Compared to Acid Scarification and Cold Stratification Methods for Different Raspberry Genotypes
    (2023) Pergolotti, Valeria; Marcellini, Micol; Contreras, Elida; Mezzetti, Bruno; Gambardella, Marina; Capocasa, Franco; Sabbadini, Silvia
    In raspberry (Rubus idaeus L.) breeding programs, seed double dormancy causes delayed and low germination rates. In this study, an in vitro germination protocol was developed to increase raspberry seed germination rate and decrease germination time. This protocol was optimized on the cultivars "Polka" and "Tulamagic", specifically, their open-pollinated seeds, by applying two different cutting types (transverse, or longitudinal), followed by two different treatments (direct in vitro culture at 24 degrees C, or 2 weeks at 4 degrees C followed by in vitro culture at 24 degrees C). The best results for both cultivars were obtained when seeds were cut transversally and directly cultured in vitro at 24 degrees C (germination rate 73-78%, starting germination time 4 days after treatment). The optimized in vitro protocol was applied to 14 different combination crosses, observing a germination frequency around 87%, and speed in line with "Polka" and "Tulamagic". These results were compared to those from the 14 cross combinations having undergone acid scarification (95% H2SO4 for 30 min) and cold stratification (3 months), which, in comparison, only yielded a 25% average germination rate. The optimized in vitro protocol favors high germination efficiency for all raspberry genotypes tested, and presents advantages for the standardization of germination time and reduction in the parental genotypes' impact on germination rate.