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United States Department of Agriculture

Agricultural Research Service

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Research Project: REGENERATION OF SHORT-DAY ONIONS FOR CONSERVATION AND DISTRIBUTION

Location: Plant Genetic Resources

2011 Annual Report


1a.Objectives (from AD-416)
The objective of this cooperative research project is to regenerate accessions of the short-day Allium cepa collection maintained at the Plant Genetic Resources Unit (PGRU) of Geneva, NY. These accessions will be regenerated because of either reduction of viability below acceptable standards and/or low seed supply due to seed distributions. These accessions must be regenerated so that the short-day onion germplasm collection may be distributed. Short-day onions cannot be regenerated at Geneva, NY because of short day length requirements to initiate flowering and also to initiate bulbing. Short day onions require a day length of shorter than 13 hours to initiate bulbing and flowering, whereas in Geneva during the growing season the day length is longer than this because of the latitude of Geneva. Therefore, there is a need for regular routine regeneration of these accessions on a recurring basis.


1b.Approach (from AD-416)
The vegetable curator at Geneva, NY will identify the short-day onions that require regeneration. The accessions that are in most need of regeneration each year will be prepared and sent to New Mexico State University for regeneration. At New Mexico State University, the accessions will be seeded in seedling flats. Once plants have reached a large enough size, they will be transplanted to a field for bulb production. Plants will be grown over the winter. Once the plants have matured the following summer, bulbs will be collected from each accession and will be stored at ambient conditions for 3-4 months. Once bulbs begin to break dormancy, they will be set in a seed production field. The following spring, a 10’ x 10’ cage will be placed over the bulbs from each accession. Once the bulbs have flowered, blowflies will be introduced into each cage for flower pollination. After one month, the mature seed for each accession will be harvested, dried, and cleaned. The seed produced from the regeneration will be transferred to PGRU. At PGRU, the seed will be dried and germination tests conducted. Then seed stock inventory status will be updated on GRIN (Germplasm Resources Information Network).


3.Progress Report

On October 1, 2010, seed of 28 accessions and collected germplasm from a 2006 collection trip was sent from the onion breeding program at NMSU to the onion curator at the PGRU in Geneva, NY. On September 25, 2010, bulbs of 17 onion accessions and collected germplasm were placed in a cage field for future seed production in the following year. Those bulbs broke dormancy and began resprouting. On December 3, 2010, bulbs of 17 accessions were shipped from PGRU to Las Cruces for regeneration because the bulbs had begun sprouting early in storage at PGRU. Due to a cold weather spell in February, the bulbs of three accessions were lost. In April of 2011, seedstalks from bulbs emerged and the plants were covered with a frame structure and netting. Honeybees and blue bottle flies were introduced into the cage structures once flowers started to open. The pollination vectors were allowed to pollinate the flowers for six weeks. After the pollinators were removed, the plants remained in the cages for seed set. Once open capsules are visible, umbels will be harvested from each cage and will be kept separate by accession. The umbels will be allowed to dry for four weeks. Once the umbels are completely dry, they will be crushed and the seed will be extracted and cleaned. The cleaned seed will be delivered to the onion curator at PGRU during October of 2011.

On September 25, 2010, seed of two entries was sown in a flat at the Fabian Garcia Science Center in Las Cruces, NM for bulb production. On December 7, 2010 and January 19, 2011, seed of 13 accessions were sent from PGRU to Las Cruces for regeneration. These seeds were sown in flats and grown in a greenhouse. Once they were of large enough size, plants of these entries were transplanted to a field at the Leyendecker Plant Science Research Center for further bulb production. Currently, 19 accessions and germplasm lines are being regenerated for bulb production. Beginning in June of 2011, bulbs of these accessions were harvested and placed into storage until September 2011. Seed will be produced from these bulbs in the following year as described above.

Monitoring activities for this project included reports, site visits, and meetings of the Crop Germplasm Committee for onion at the American Society of Horticultural Sciences and the National Allium Research Council.


Last Modified: 10/30/2014
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