Topset Diversity in the USDA National Plant Germplasm System's Allium sativum Collection, Poster Board #411

Allium sativum L., garlic, has been cultivated for thousands of years and has primarily been propagated vegetatively using cloves and topsets/bulbols.  There are two basic types of garlic, those that produce flower stalks and an inflorescence with topsets (hardneck varieties) and those that do not(softneck varieties).  Much variation exists in the size, color, and number of bulbols per umbel in hardneck varieties.  The USDA–ARS National Plant Germplasm System Allium sativum collection contains approximately 280 accessions.  Of these accessions 59.6% are hardneck varieties that produce bulbols.  In 2010, topsets were harvested from regeneration plots of the Allium sativum collection and characterized for size, color, and number of bulbols per umbel.  Images were also taken of samples for each accession.  Topset colors ranged from cream to dark purple among accessions and occasionally within an accession.  The majority of accessions have cream colored topsets.  Four size classes were used to characterize the collection [small ( < 0.5 cm diameter), medium, large and extra large (1.5 to 2cm diameter)], with the majority in the small size class.  As with color, bulbol size varied among umbels within an accession; 31% of the accessions produced topsets in 2 size classes.  The average number of bulbols per umbel ranged from 2 (W6-10731) to over 200 (5 accessions).  The collected topset characterization data will allow the garlic collection user community to more efficiently select accessions to use for specialty crop production such as green garlic or dried products utilizing bulbols.