2.02 RESPIRATION RATE

The continued respiration of the living harvested sugar beet root is commonly cited as the major source of sucrose loss during post-harvest storage (Bugbee, 1993; Huijbregts et al., 2013; Wyse & Dexter, 1971). As a dimension of plant health, respiration rate is considered. As a biennial root crop harvested at the end of its first year of growth, sugar beet is not considered to ripen and thus it is not expected that respiration rate will vary with timing of harvest (Elliott & Weston, 1993; Scott & Jaggard, 1993). Evidence that this has been tested could not be found. Differences in baseline respiration rate have been observed between varieties during post-harvest storage (Lafta & Fugate, 2009; Stout & Smith, 1950), but these are relatively minor in comparison to the differences observed when there is an interaction with other dimensions of plant health or the storage environment. As such, the discussion on respiration rates during post-harvest storage are interspersed throughout the following discussion on the principles of long-term post-harvest storage of sugar beet roots.