Evaluation of Resistance to Bolting in Two Sugar Beat Generations Developed from Two Tetraploid Populations

Autumn sugar beet planting demands less water than spring, however, one of the main requirements of autumn planting is bolting-resistant cultivars. Depending on the climatic conditions of the sugar beet growing region, different levels of bolting-resistance is required. The aim of the present study was to develop and evaluate sugar beet pollinators resistant to bolting based on half-sib genotypes selection. In October 2010, 250 half-sib families developed from two tetraploid populations 12460 and 12650 were grown and screened for bolting resistance in Oltan Agricultural Research Station in Moghan, Ardabil, Iran. Based on the results of bolting evaluation, four and one resistant populations were selected from 12460 and 12650 populations, respectively. In 2013, 120 families were developed from four populations of 12460 and 90 half-sib families were developed from single population of 12650. Selected families together with parental populations, four resistant and one susceptible controls were grown in autumn in 2013-14 and 2014-15 in randomized complete block design with three replications, in Moghan. Considerable variation was found among half-sib families for bolting resistance. Ninety-eight families in population 12460, and 47 families in populations 12650 showed significantly higher resistance than parental population illustrating the positive effect of selection for bolting resistance. Narrow-sense heritability for bolting resistance was estimated 85% and 66% for half-sib families developed from 12460 and 12650 populations, respectively.