Emily Follett
Research Scientist
(+47) 950 05 357
emily.follett@nibio.no
Place
Ullensvang
Visiting address
NIBIO Ullensvang, NO-5781 Lofthus
Abstract
The positive effects of the commonly used commercial treatments of 1-MCP and CA storage on apple are well known and implemented for a range of cultivars in many countries. However, as both technologies demand investments and require additional annual user costs, the decision of implementation must be taken based on the predicted benefit obtained in the specific conditions. The main cultivar in volume in Norway, ‘Red Aroma’, commonly has a main sale period from about two to maximum eight weeks after harvest, in part due to market preferences. However, without additional treatments, the cultivar is often unmarketable after eight weeks due to a combination of firmness loss regardless of storage temperature and soft scald development, with further impacts of variation in ripening at harvest and decay development during storage. Possible improvement in shelf-life quality of fruit stored for about eight to 10 weeks either in CA, or in combination with 1-MCP, were explored through a holistic perspective in industrial scale experiments. Differences in effects of the treatments on multiple commercial deliveries, between seasons, packinghouses, and varying fruit sizes were found. Possible reasons for these differences as well as opportunities for improvements at the packinghouse level will be discussed.
Authors
Theresa Weigl Jorunn Børve Emily Follett Ingunn Øvsthus Carl Gunnar Fossdal Hanne Larsen Siv Fagertun RembergAbstract
The mid-early-ripening cultivar ‘Summerred’ is popular among consumers and widely grown in Norway. However, ‘Summerred’ fruit is prone to rapid softening and development of senescence-related disorders, especially senescent breakdown. Calcium can have a significant role in maintaining firmness and delaying senescence of fruits. In a two-year study, foliar application of calcium chloride (CaCl2) was conducted six times, with varying weather conditions between the growing seasons. Fruit was harvested at optimal commercial maturity and stored at 4°C for either 6 or 9 weeks, followed by simulated shelf-life conditions at 20°C. Ethylene levels were monitored during storage to detect ripening discrepancies. At harvest, CaCl2-treated fruit exhibited significantly lower ethylene production compared to untreated fruit, although no differences were observed at the end of the storage period. Senescent breakdown showed significant variability between the two seasons, with an incidence of up to 15% in the first season and nearly no incidence in the second. Senescent breakdown increased with storage duration but was unaffected by foliar CaCl2 application. Real-time PCR analysis of fruit flesh samples revealed increased expression of polygalacturonase and β-galactosidases genes after storage, indicating their involvement in apple softening. Notably, there were no differences in gene expression between CaCl2-treated and untreated fruit after storage. Expression patterns of genes involved in ethylene biosynthesis at harvest were different between the two seasons. Higher expression was observed in the year with greater disorder development, indicating greater maturity at harvest. There were no significant differences in the Streif index between the two years.
Abstract
No abstract has been registered