Role of Different Abiotic Factors in Inducing Pre-Harvest Physiological Disorders in Radish (Raphanus sativus)

Radish, one of the important root vegetables, is widely grown in the world due to its easy cultivation, short duration, growing habit, and adaptability to various growing conditions. However, it is still extremely difficult to produce good quality radish roots due to its vulnerability to different preharvest physiological disorders. Important physiological disorders that significantly reduce the yield and quality of radish are forking, pithiness/sponginess, cracking/splitting, hollowness, and internal browning. Different abiotic factors like moisture stress, temperature fluctuation, growing medium, nutrient imbalance, plant density and harvesting time cause a disturbance in the metabolic activities of root tissues that produce non-marketable roots. Therefore, this review provides a detail insight on the causes, physiology of these disorders, and the management practices to prevent them to produce commercial quality roots. This comprehensive knowledge will not only help the growers, but it will provide relative information for researchers as well to control these disorders through breeding innovations and biotechnological tools.

Postharvest calcium chloride application maintains shelf life and quality of loquat (Eriobotrya japonica L.) fruit

Loquat (Eriobotrya japonica L.) is an important sub-tropical fruit with very limited postharvest life. Therefore, in the current study, we investigated the effect of calcium chloride (CaCl2) treatments on the shelf life and quality of loquat fruit. After harvest loquat fruit treated with different concentrations of CaCl2 viz. 2%, 4% and 6% for 2 min were kept at room temperature (30±2oC) for 5 and 10 days. Untreated fruit were kept as control. The results showed that fruit treated with 6% CaCl2 exhibited minimum fruit weight loss (9.1%), external browning (8.83%), and internal browning (9.1%) after 10 days shelf period in contrast with control fruit. Lowest total soluble solids contents (9.11%), highest titratable acidity (0.53%) and juice (28%) contents were found in fruit treated with 6% CalCl2 as compared to other treatments. In conclusion, among the tested treatments, application of highest level of CaCl2 (6%) effectively maintained the quality of loquat fruit a room temperature.

Occurrence of Physiological Browning Disorders in Stored ‘Braeburn’ Apples as Influenced by Orchard and Weather Conditions

Physiological storage disorders continue to cause sizable economic losses in a range of commercially important pomefruit cultivars. Given similar storage regimes, the incidence and severity of browning disorders in the apple cultivar ‘Braeburn’ can vary in different years in a way that can be explained by the interaction of preharvest seasonal and orchard factors. Over a three-year period (2016 to 2019) at the Kompetenzzentrum Obstbau-Bodensee (KOB) in Southwest Germany a range of orchard and storage treatments were conducted for: air temperature during cell division for three weeks post petalfall or during four weeks preharvest, calcium orchard sprays, crop load and harvest timings. Following controlled atmosphere (CA) storage, the disorder incidence for internal browning and cavity formation varied markedly over the three different growing seasons. Crop load treatments strongly influenced the expression of browning disorders in all years. Differences in air temperatures (△ +/- 2 °C compared to ambient) during the cell division period showed little effect on browning incidence. Warm night temperatures (>10 °C) prior to harvest can reduce internal browning in ‘Braeburn’ apples during CA storage and shelf-life.

Internal browning control in ‘Laetitia’ plums by modified atmosphere, management of ethylene and storage temperature

The objective of this study was to evaluate the effect of modified atmosphere (MA) and 1-methylcyclopropene (1-MCP) treatment on low storage temperature (1.5 °C) and 1-MCP treatment on high storage temperature (8.0 °C) on fruit quality of ‘Laetitia’ plums, mainly on internal browning. The treatments evaluated were 1.5 °C; 1-MCP (1.0 µL L-1) + 1.5 °C; MA + 1.5 °C; 1-MCP + MA + 1.5 °C; 8.0 °C; 1-MCP + 8.0 °C. Fruit were stored for 30 and 40 days, followed by three day of shelf life. For fruit stored at 1.5 °C, the treatment with 1-MCP associated to MA provided higher flesh firmness, less intense skin red color and reduced occurrence of internal browning in comparison to the fruit stored at 1.5 °C of the remaining treatments, for both periods of storage. In fruit not treated with 1-MCP and stored at 8.0 °C there was no occurrence of internal browning, despite of lower flesh firmness and more intense red color of the skin and flesh in comparison to the fruit stored at 1.5 °C. The treatment with 1-MCP in fruit stored at 8.0 °C delayed those changes of flesh firmness and red color of the skin and flesh assessed after 30 days of storage, followed by three days of shelf life. The MA, regardless of 1-MCP treatment, had fruit with higher production of acetaldehyde after 30 days of storage, and ethanol after 30 and 40 days of storage at 1.5 oC. In fruit stored at 1.5 °C without MA, the treatment with 1-MCP reduced the production of ethyl acetate, acetaldehyde and ethanol. Fruit stored at 8.0 °C, regardless of 1-MCP treatment, had the lowest production of acetaldehyde and ethanol.

Physiological disorders.

Guavas are highly perishable fruits where the production and postharvest quality of guava are affected by micronutrient deficiencies that can lead to physiological disorders. Environmental variables such as temperature, light, aeration and nutritional imbalances can also result in a disturbance in the plant metabolic activities and cause physiological disorders. It is crucial to understand several technical terms which identify the physiological and nutritional disorder symptoms, especially on guava fruit; for example, bronzing, chlorosis, lesion, scorching and others. This chapter discusses primary physiological disorders, including chilling injury, external and internal browning, sunscald, bronzing, fruit drop and nutrient deficiency.