Abstract
Two traits that could enhance sugar beet production are bolting tolerance and disease tolerance/
resistance to post-harvest storage pathogens. Bolting refers to the elongation of
the stem usually followed by flowering; sugar beets are biennial, requiring vernalization
(prolonged cold period) to induce bolting. Improving bolting tolerance in sugar beet roots
could prolong the growing time of sugar beets, make winter beets a more viable option for
the industry and increase sucrose content. Sucrose losses caused by post-harvest storage
pathogens can be significant, particularly in areas where storage piles are unable to remain
frozen. Developing tolerant/resistant sugar beets to post-harvest storage pathogens could
increase sugar recovery during prolonged storage. To understand the effect of cold storage
in sugar beet roots, we (1) phenotypically characterized bolting and disease susceptibility
for eleven genotypes from the USDA-MSU germplasm across variable durations of cold
treatment at 4°C and (2) analyzed the transcriptomic changes for three of those genotypes
across cold durations of 0, 4, 8, 13 and 17 weeks. We observed differences in bolting response
between genotypes and within plants of each genotype. The number of bolting
plants increased as cold storage time increased, and the time between planting and bolting
decreased as cold storage period increased. For the disease susceptibility, we observed larger
lesions caused by B. cinerea compared to F. gramminearum. Subtle differences in lesion
diameter were noted across genotypes for both pathogens. Larger lesion diameter caused
by B. cinerea was noted as cold storage period increased across genotypes. Differences in
transcriptomic response associated with bolting and disease susceptibility were detected.