In order to diagnose the nutritional disorders caused by various environmental stress, biochemical test, xylem sap analysis and colorimetric petiole analysis were used to assay symptoms well before the severe development. Among the various enzymatic analysis, alkaline phosphatase activity was highly specific to calcium deficiency while in vivo nitrate reductase activity was not stable parameter in response to nitrogen deficiency. Determination of nitrogen, phosphorus and magnesium by colorimetric petiole analysis was sensitive to induced deficiencies. The status of potassium in the plant, however, could be better determined with the xylem sap analysis. Salinity stress induced by low osmotic potential of the nutrient solution increased the activity of alkaline phosphatase, showing similar results as calcium deficiency. Magnesium and phosphorous contents by the colorimetric petiole analysis were particularly low when the roots in anoxia.
Seong-Hee Lee, Soon-Ho Ha and Gap-Chae Chung
Natalia Salinas, Zhen Fan, Natalia Peres, Seonghee Lee and Vance M. Whitaker
FaRCa1 is a major locus conferring resistance to anthracnose fruit rot (AFR) caused by Colletotrichum acutatum, an important pathogen of strawberry (Fragaria ×ananassa). The objective of this study was to characterize the effects of FaRCa1 on anthracnose root necrosis (ARN) via root inoculations and DNA marker characterization of the locus. A subgenome-specific high-resolution melting (HRM) marker for an insertion/deletion (InDel) near FaRCa1 was designed using the ‘Camarosa’ octoploid reference genome. The marker was used to genotype cultivars and advanced selections studied in two seasons. A root disease screening method was developed in which roots were cut and dipped in a spore suspension before planting, using a mixture of three local isolates of the C. acutatum species complex. ARN was indirectly scored by calculating image-based leaf area differences among inoculated and noninoculated plants. The allele of FaRCa1 conferring resistance to AFR also conferred a significant reduction in ARN. Thus, a robust and easily scored DNA test is now available to breeders for selecting for resistance to both the fruit and root forms of strawberry anthracnose.
Youngjae Oh, Jason D. Zurn, Nahla Bassil, Patrick P. Edger, Steven J. Knapp, Vance M. Whitaker and Seonghee Lee
The availability of strawberry (Fragaria ×ananassa) genomic resources has increased dramatically in recent years. Some of these resources are readily applicable to strawberry breeding programs for use in DNA-informed breeding. Information about these tests and how to interpret them is dispersed through numerous manuscripts or in the laboratories that use them routinely. To assist breeders in identifying tests available to their breeding program and in implementing them in their program, a compendium of strawberry DNA tests was created. This compendium is available for download from the Genome Database for Rosaceae (https://www.rosaceae.org/organism/Fragaria/x-ananassa?pane=resource-4). This resource will be updated continually as old tests are modified and new tests are created.