Bidirectional Recurrent Half‐Sib Family Selection for Geosmin Concentration in Table Beet

Abstract

Geosmin (trans‐1,10‐demethyl‐trans‐9 decalol) is a terpene derivative produced by Streptomyces spp., various cyanobacteria, and fungi in the soil. Geosmin is also responsible for the earthy flavor of the table beet. Geosmin in beet, spinach, and Swiss chard can be a deterrent to the consumption of these foods, while other consumers desire their earthy flavors. While it is known that microbes are capable of producing geosmin, it is not clear if geosmin associated with beets is microbial in origin. The objective of this investigation was to determine if table beet populations were responsive to selection for geosmin concentration. Four cycles of bidirectional half‐sib recurrent selection for geosmin concentration were conducted in table beet, resulting in low (LGC) and high (HGC) geosmin concentration populations. The LGC mean shifted from 17.3 µg geosmin kg–1 tissue in Year 1 to 4.3 µg geosmin kg–1 tissue in Year 3. The HGC mean shifted from 22.3 µg geosmin kg–1 tissue in Year 1 to 33.8 µg geosmin kg–1 tissue in Year 3. This trend continued after evaluation of selected families in Year 4. Positive and negative response to bidirectional recurrent selection for geosmin concentration is one indication that geosmin may be endogenously produced by beets.