Institut für Züchtungsforschung an Obst
Fruit quality of strawberries is severely compromised by rain. An important disorder arising from rain is ‘water soaking’. The symptomatic fruit surface has a light greyish color and a translucent and deliquescent appearance. Water soaking is associated with microcracking of the cuticle and anthocyanin leakage from the epidermal cells. The incidence of fruit rots pre- and postharvest is increased causing significant economic loss. As a result, strawberry production is shifting from open-field, to semi- or fully-protected in plastic tunnels or greenhouses. Genotypes differ in susceptibility to water soaking. The physiological, genetic and molecular bases for such differences are not understood. (1) We will establish a developmental time course of differential gene expression (RNA-seq), water soaking, cuticle deposition, strain development and microcracking for a pair of parental genotypes selected for their contrasting susceptibilities to water soaking. (2) The parental genotypes will be crossed to produce an F1-population (200 individuals) to perform (i) phenotyping of the segregating F1-population for susceptibility to water soaking, (ii) genotyping for developing genetic linkage maps, (iii) QTL analyses and (iv) develop PCR-based molecular markers flanking the QTL regions for marker-assisted breeding. (3) We will select the most promising candidate genes (CGs). This will allow establishment of a first molecular model for tolerance to water soaking. The model including the identified CGs will be verified by further expression studies using qRT-PCR in independent growing seasons. Finally, we will sequence the most promising CGs in parental genotypes, identify structural variations and develop PCR-based markers for the detection of selected structural variations. The structural variations and their association with water soaking will be verified using the F1-population.
German Research Foundation
