Location: Crop Improvement and Protection Research
Project Number: 2038-22000-019-015-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Nov 1, 2020
End Date: Jun 30, 2023
Disease caused by Macrophomina phaseolina is a serious constraint on strawberry production in California. Robust resistance is not currently available in cultivars, and little is known about alternatives to soil fumigation for management of this disease. The goal of this project is to accelerate efforts to breed Macrophomina-resistant strawberry cultivars and test non-fumigation methods for disease reduction. The outcomes of this project will be significant progress by strawberry breeding programs in producing cultivars with resistance to Macrophomina, novel methods for disease control that do not rely on fumigation, and critical information on the genomics of resistance to this pathogen. These results will enable producers to increase revenue. Success of the project will be measured by surveys of breeding programs, the number of resistant cultivars released, grower adoption and interest in cultural techniques, and industry attendance at presentations of our research. Objectives: • Provide a field location where breeding companies can screen strawberry germplasm for resistance to Macrophomina. • Conduct transcriptomics on resistant and susceptible strawberry varieties to identify differentially expressed genes related to the resistance phenotype. • Assess the impact of removing Macrophomina-infested crown debris (a possible inoculum source) on disease severity and yield. • Investigate novel approaches to anaerobic soil disinfestation for reducing populations of Macrophomina.
We will invite breeding programs to screen germplasm for resistance for two consecutive years at Macrophomina-infested fields in San Luis Obispo and Salinas. Strawberry seedlings resulting from crosses of resistant cultivars will be planted at these locations to determine the heritability of resistance. Planting will be done in Oct 2020 for Mar 2021 – Sep 2021 disease severity scoring, and in Oct 2021 for Mar 2022 – Sep 2022 disease severity scoring. The postdoctoral researcher will carry out transcriptomics experiments and collect DNA from mapping populations in Mar 2021 – July 2021 and conduct genomic and transcriptomic data analysis will be conducted during Mar 2022 – Dec 2023. Breeding entities will be surveyed in January 2023 for the number of advanced selections and/or cultivars resulting from this work. Two field trials were established in 2019 to test crop debris removal on subsequent disease severity and yield. Both fields had severe Macrophomina infestations. Strawberries will be planted in these fields in Nov 2020. Disease severity and yield data will be collected in Mar 2021 – Sep 2021 (PMH). Mechanization of crop debris removal will be investigated in Oct 2021 – Oct 2022. Controlled experiments on anaerobic soil disinfestation with inexpensive hay carbon sources will be conducted in Nov 2020 – Jun 2021. Field trials of anaerobic soil disinfestation with hay carbon sources will be conducted Jul 2021 – Oct 2021. Yield data will be collected from Mar 2022 – Sep 2022. Results will be disseminated at 2-3 grower meetings per year for the duration of the project. Results will be written for publication in fact sheets, websites, and peer reviewed publications during Jan 2022–Apr 2023.