Identification of tetraploid pollinator resistant to leaf spot disease and bolting in sugar beet

To determine tetraploid pollinators resistant to Cercospora leaf spot disease and bolting with optimum yield and quality, five tetraploid pollinators were crossed with a male sterile line, SB17. The hybrid seed was harvested from the male-sterile line. The hybrids together with four controls including resistant and susceptible cultivars (a total of 9 cultivars), were evaluated in a randomized complete block design with four replications in autumn sowing over two years in Dezful, Khuzestan, Iran. The yield stability of the hybrids was evaluated in spring sowing over two years in Karaj. Combined analysis results showed that hybrids SB17 * Jot-18 and SB17 * B65T had the lowest infection index (3.12 and 3.93, respectively) and bolting rate (0.87 and 0.75%, respectively). Based on sugar yield results obtained from Dezful experiment, hybrids were classified in three clusters in which hybrids SB17 * Jot-18, SB17 * B65T, Monotona, and Leila were placed in one group. The hybrid SB17 * B65T had the highest sugar yield (7.13 t/ha) in Karaj. It is suggested that the tetraploid pollinator B65T can be used in breeding programs to produce leaf spot disease and bolting resistant hybrids.