18 research outputs found
Relationship of beet curly top foliage ratings to sugar beet yield
Sugar beet (Beta vulgaris) varieties were evaluated for disease resistance to curly top to establish
if disease ratings made in inoculated nurseries correlated with disease ratings and yield in sugar
beet crops exposed to natural disease outbreaks. Cultivars were planted both in inoculated curly
top nurseries in Kimberly, ID, and in commercial cultivar trials in irrigated fields near Ontario,
OR and Nampa, ID. Plants were evaluated for curly top using a rating scale of 0 (no symptoms)
to 9 (dead). Moderate disease pressure in the Ontario (mean rating = 3.8) and Nampa (mean
rating = 4.1) fields resulted in significant differences for disease rating, root yield, sugar content,
and estimated recoverable sugar among cultivars. Disease ratings from both commercial fields
were positively correlated (r = 0.91 and 0.82, P < 0.0001) with ratings from the inoculated nurseries.
In commercial fields, root yield was negatively related to disease rating (r2 = 0.47 and
0.39, P ? 0.0004). For each unit increase in disease rating (increasing susceptibility), root yield
decreased 5.76 to 6.93 t/ha. Thus, curly top nurseries reliably predict curly top resistant cultivars
for commercial cultivatio