Project Number: 2072-21000-058-000-D
Project Type: In-House Appropriated
Start Date: Feb 13, 2018
End Date: Feb 12, 2023
Objective 1: Characterize important genetic traits in blueberry, blackberry, and raspberry to improve selection efficiency and identify novel sources of genetic resistance to disease. Objective 2: Breed improved blueberry, blackberry, and raspberry cultivars for the commercial fruit industry including high yielding, virus tolerant, high-quality fruits for the fresh and processing markets.
For each crop, a modified recurrent mass selection system will be used. Individuals that are selected in a given generation will be intercrossed to produce the next generation. For Rubus spp. and strawberry 4000-6000 seedlings, and 2500-4000 blueberry seedlings from 30-100 crosses will be evaluated annually. Approximately 0.5 to 1.0% of the seedlings are selected based on subjectively evaluated fruit quality, plant performance, ripening period, and yield. Frozen samples will be evaluated for processing characteristics. Selections identified as being superior will be propagated for commercial trial and release. For nursery production, the ARS virology program in Corvallis, OR will help produce virus-tested propagation material. To broaden the germplasm base, superior individuals or representatives of superior populations of small fruit species will be crossed among themselves or with advanced selections or cultivars. Selections from these crosses will be used in our breeding program and distributed to other breeders. Emphasis will be on aphid resistance, disease resistance, fruit quality, thornlessness and tolerance to abiotic stresses associated with growing these crops in regions with more diverse climates. This program collaborates with molecular geneticists in efforts to bridge the gap between genomics and applied plant breeding in berry crops. Our program helps to determine the mapping populations to develop or genotypes to include and how the various phenotypic traits (phenological, reproductive, and vegetative) will be evaluated. The phenotyping for each project is being coordinated across multiple locations with different climatic conditions. For raspberry leaf curl disease, suspect raspberry samples will be collected and their virome analyzed using Next Generation Sequencing. This approach will also be used to examine two novel diseases of grapevines in Oregon. Diagnostic assays will be developed and used for epidemiology studies, certification and quarantine purposes. Virus vectors will be identified and strategies for vector control developed as a means to manage virus diseases. Total genomic sequencing of five Rubus cultivars will be used to determine if the inserted RYNV sequences represent full-length or partial RYNV and if all insertions are at the same site. If the RYNV insertions are at the same site in each of these cultivars it would indicate that the insertion may have happened once and been passed on in breeding programs. Several approaches will be tested for applying gene silencing as a tool to eliminate viruses from growing points of plants (meristematic dome and several leaf primordia): 1. Virus specific dsRNA will be produced and provided to plants in tissue culture as an additive to the media; 2. dsRNA will be attached to positively charged clay nanoparticles and sprayed on plants in tissue culture or growth chambers; and 3. RBDV infected plants will be grafted onto transgenic plants (already developed red raspberry) that are producing RNAi silencing of RBDV. Meristems will be collected at various times after treatments, plants regenerated and tested for RBDV.