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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Plant Germplasm Preservation Research » Research » Research Project #435085

Research Project: Strategies for Long-Term Conservation of Vegetative and Seed Germplasm of Prunus Species (Apricot, Cherry, Plum, Almond, and Peach) in Genebanks

Location: Plant Germplasm Preservation Research

Project Number: 3012-21000-016-10-T
Project Type: Trust Fund Cooperative Agreement

Start Date: Jul 1, 2018
End Date: Aug 31, 2019

Objective:
The overall project objective is to improve the conservation of Prunus collections in Egyptian and USDA genebanks. The USDA portion of the project focuses on developing technologies to securely back-up the Prunus collection maintained at the National Clonal Germplasm Repository for Tree Fruit and Nut Crops and Grapes in Davis, California as part of the National Plant Germplasm System (NPGS). The NPGS Prunus collection inventory includes materials that are classified as cultivars and are thus vegetatively propagated by grafting. These accessions are valued for their specific genotypes and will be backed-up by cryopreserving vegetative propagules (shoot tips). A portion of the trees in the Prunus collection originated from wild-collected seeds. These individuals are valued for the genetic diversity they represent, rather than for their specific genotypes. Seeds (either self-pollinated or cross-pollinated) can be conserved to capture the diversity of these accessions of wild origin. The literature suggests that Prunus seeds generally exhibit orthodox seed storage behavior, but long-term storage methods are not fully established. USDA Objectives: 1) Develop cryopreservation methods for vegetative tissues of Prunus cultivars 2) Develop and implement seed conservation for accessions representing wild Prunus species in the USDA genebank 3) Compare Egyptian historic Prunus cultivars to those in the USDA genebank using genetic and genomic techniques The Egyptian portion of the project focuses on collecting historic Prunus cultivars (peaches, apricots, and almonds) from sites throughout Egypt and re-patriating Prunus cultivars that originated in Egypt that are available in other national genebanks. The Egyptian Prunus collection is composed of cultivars which will be characterized using standardized morphological descriptors. In collaboration with USDA scientists, the Egyptians will also perform research to develop cryopreservation methods for vegetative tissues of Prunus cultivars. In addition, current and historic Prunus cultivars from Egypt will be compared to accessions represented in the USDA genebank using genetic and genomic techniques. Egyptian Objectives: 1) Identify and collect historic apricot, peach, and almond cultivars in Egypt and from international genebanks 2) Use standardized morphological descriptors to characterize the Egyptian Prunus collection 3) Develop cryopreservation methods for Prunus cultivars 4) Compare Egyptian Prunus cultivars and those in the USDA genebank using genetic and genomic techniques

Approach:
Many countries, including the US and Egypt, maintain Prunus (apricot, cherry, plum, almond, and peach) genetic resource collections within ex situ genebanks. Accessions are made available to scientists for research and breeding purposes. It is expensive to maintain these collections in field and greenhouse conditions. These collections are also vulnerable to environmental and biotic threats. Our Egyptian collaborators will collect historic Prunus cultivars from communities in Egypt and from other national genebanks and add them to the Egyptian genebank collections. The Egyptian collection will then be characterized using morphological descriptors. The Prunus cultivars in the Egyptian collection will then be genotyped and compared to those in the USDA genebank to identify novel genetic resources. USDA's role will be to develop strategies to securely back-up vulnerable field collections of Prunus in the Egyptian and USDA genebanks in long-term storage at the National Laboratory of Genetic Resource Preservation (NLGRP). Cultivars to be preserved as clones will be processed as shoot tips and cryopreservation research will identify cryoprotectant solutions, desiccation time-courses, and freezing rates to obtain high survival following liquid-nitrogen exposure. In addition, we will identify accessions that can be more effectively stored as seeds, such as those originating from wild populations or historically grown from seeds. For these studies, our primary research goals will be developing methods to predict the longevity of seeds given different genetic backgrounds and relative humidity and temperature treatments and assess seed viability non-invasively.