SOW Avocado Mapping Population Regeneration.pdf

Statement of Work for SHRS Florida Avocado Mapping Population Regeneration Project

Scope: The USDA-Agricultural Research Service National Plant Germplasm System maintains collections of economically important crop accessions as well as research plantings being evaluated for segregation of important agronomic and horticultural traits. In 2007 1425 seedlings of avocado cultivars “Simmonds” (West Indian Race – “A” type flower) and “Tonnage” (Guatemalan X West Indian race hybrid – “B” type flower) were planted at SHRS. Each of the seedlings were originally from fruit obtained from a commercial orchard interplanted with both cultivars. These two cultivars were used due to the unique flowering mechanism thought to promote outcrossing and increased fruit yield. Each seedling had been verified using microsatellite markers to be either “Simmonds” X “Tonnage” or “Tonnage” X “Simmonds” hybrids. This population is one of the rarest avocado mapping populations generated between two different ecotypes (West Indian x Guatemalan, and Guatemalan x West Indian). This population will be useful for understanding genetics of multiple quantitative traits, which in turn will be useful for determining for breeding purposes. This population is under threat from diseases and therefore there is an urgent need to safeguard it by grafting it on a suitable rootstock.

Project Requirements: The project would be contracted to a local reputable nursery with extensive experience in commercial avocado propagation, consistent labeling protocols, extremely high sanitation standards, facilities required to irrigate and apply chemical fertilizers and pesticides, as well as proficiency working with research staff. A local nursery is required to minimize the amount of possible damage in transport. To minimize the potential of using ASBVd (viroid) infected rootstock, SHRS will provide the required amount of rootstock seed for the project. The seed will be from the cultivar “Waldin” from the SHRS collection and/or a local nursery using openly pollinated seed from a single cultivar which will allow more uniformity in the new planting for data collection and grove maintenance.

SHRS staff will work with the contracted nursery on budwood collection, transport of seeds and plants, and clarification on any labeling issues. The SHRS has the genetic database to verify the identification of individual clones if required. The vendor will be required to do the grafting and labeling, as well as communicate any needs such as additional budwood material of clones that were not successfully grafted (i.e. graft failure) and communicate the ongoing inventory of successful grafts. A requirement of a total of three grafts of each individual tree in the population which will amount to a total of 900 trees.

Due to the size of the population and the availability of Waldin rootstock, the grafting will be done on annual intervals totaling 300 grafts.

Deliverables:

Number of different avocado line/variety: 300

Number of grafts per line/variety: 3

Total number of grafted trees: 900

Rootstock: Waldin