Water-soaking and cracking in strawberry: Mechanism and causes

• Applicant: Professor Dr. Moritz Knoche
• Subject Area: Plant Cultivation, Plant Nutrition, Agricultural Technology
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 426627435

Mature fruits of strawberry show very limited rainfastness. First, their wetted skins soon show signs of water-soaking and, second, this is quickly followed by a progressive disintegration of the underlying flesh tissues. Neither problem is at all reversible upon drying. Protected cultivation is the only measure currently available that reliably limits these problems but this significantly increases the cost of production. A third problem is the rapid softening of the fruit once maturity is reached – both pre- and post-harvest. These three factors dominate in the determination of fruit quality at point of sale. Here, we set out to investigate the hypothesis that all three phenomena are directly or indirectly related to fruit water relations. Our objectives are to identify the mechanistic bases of water soaking and cell rupture in the flesh. We will focus on: (1) characterising the cytology of the skins of strawberry fruit - with and without signs of rain damage, (2) determining the rate of water transport into the fruit through the stalk, (3) quantifying the rates of fruit water loss (transpiration) through the fruit surface and (4) establishing the effects of calcium and turgor on: (i) fruit firmness, (ii) cell-wall swelling, (iii) tissue fracture mode and (iv) susceptibility to rain damage. We expect to obtain the underpinning information required to understand the physiology of strawberry fruits and their quality and to determine how these are affected by fruit water relations. This information is required to develop strategies to mitigate rain damage (water soaking, flesh disintegration) and to help maintain fruit firmness via both altered production methods and fruit breeding.

• DFG Programme: Research Grants