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United States Department of Agriculture

Agricultural Research Service

Research Project: Evaluation of Fragaria Vesca (diploid) Strawberry Germplasm for Remontancy and Thermotolerance

Location: Genetic Improvement for Fruits & Vegetables Laboratory

Project Number: 8042-21220-254-01-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 15, 2013
End Date: Sep 14, 2016

The objective of this project is to evaluate the existing Fragari vesca (strawberry) germplasm from the National Germplasm Repository in Corvallis, Oregon ( for the ability to flower and set fruit independent of day length under elevated temperatures typical of temperate zone summer months.

Plants are obtained from the Germplasm Repository as stolons or seed. Plants established in the greenhouse are assessed for day neutrality and scored for pedicel length, flower and receptacle diameter, pollen production and viablility when grown under long days at standard temperatures over a six month period. Plants exhibiting continuous flowering and viable pollen production will be vegetatively propagated from runners or by separating crowns and moved to controlled environment chambers. Plants grown under long days at elevated temperatures (32C day/25C night) will be scored for number of inflorescences and number of flowers per inflorescence. Clonally replicated plants remaining at control conditions (25C day/20C night) will also be scored. Following manual pollination, the fruit set, fruit size, and number of fertilized achenes will be scored in experimental and control plants. Digital images will be made along with additional notations of plant morphology. Evaluation of thermotolerance of reproductive organs will be made by subjecting inflorescences to heat shock for 2 hours at 37 degrees C and assessing damage to floral organs as degree of browning or tissue deterioration at 7 days after treatment, filament lengths, and pollen viability. Germplasm identified as exhibiting improved flower and fruit production at elevated temperatures will be used for identification of genes responsible for the observed traits.

Last Modified: 10/17/2017
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