Abstract 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.

Resumo Argylia radiata é uma planta herbácea perene nativa do norte do Chile e uma espécie representativa do “Deserto Florido”. Por suas flores vistosas e outras características morfológicas, A. radiata possui grande potencial ornamental. Em trabalhos anteriores, uma descrição morfoanatômica profunda foi feita, mas os protocolos de micropropagação, que poderiam ser usados para fins comerciais, não são conhecidos. Ensaios anteriores mostraram que a suplementação de citocinina melhora a taxa de multiplicação, mas produz necrose apical nas microplantas. Para evitá-lo, diferentes modificações do meio de crescimento foram testadas, incluindo suplementação de nitrato de cálcio; aumento da concentração de ágar; enriquecimento de ácido indol-3-butírico; e mudança da formulação do meio basal. Foi avaliado o efeito dessas mudanças sobre o nível de dano, número de brotações, taxa de multiplicação, altura da planta (cm), massa fresca e massa seca (g) e teor de água (%) das microplantas. O uso da formulação McCown Woody Plant como meio basal apresentou o melhor efeito, reduzindo o nível de danos e melhorando a taxa de multiplicação. Além disso, a suplementação com IBA foi eficaz na redução dos danos necróticos. No entanto, 0,1 mg L-1 de AIB diminuiu significativamente a taxa de multiplicação, enquanto 0,01 mg L-1 levou a uma taxa de multiplicação maior do que as plantas cultivadas no meio controle. Em conclusão, o uso do meio McCown Woody Plant e suplementação com IBA deve ser considerado na micropropagação comercial de A. radiata.

ABSTRACT 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 °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 °C. In the second experiment, ‘Santa Catalina’ was stored at 0 and 4 °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’ (~ 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 °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.

ABSTRACT In recent years, crown and root rot of strawberry (Fragaria ×ananassa Duchesne ex Rozier) caused by Macrophomina phaseolina (Tassi) Goid. has affected strawberry production areas worldwide, and in developed countries its emergency has been attributed to the replacement of methyl bromide. The disease was reported in strawberry crop in Chile in 2013, in fields without fumigation. The use of resistant cultivars rises as an alternative to the management of this disease. The objective of this study was to perform a biological and molecular characterization of isolates obtained from two growing regions in Chile and Spain. A total of 35 isolates were characterized for mycelial growth at different temperatures and for chlorate sensitivity. Seven simple sequence repeat loci were used for genetic characterization. Differences were found between Chilean and Spanish isolates in both characterizations. The optimal temperature for mycelial growth was lower in Chilean than in Spanish isolates (30 and 35 °C, respectively). Meanwhile, Chilean isolates were more sensitive to chlorate. In terms of genetic characterization, Polymorphism Information Content (PIC) ranged from 0.38 to 0.85, two main groups were identified, the first group included Spanish isolates and the second group corresponded to Chilean isolates, results were supported by a population structure analysis. This study determined clear differences between two populations of Chilean and Spanish M. phaseolina isolates as causal agent of crown and root rot of strawberry.