Improvement and selection for drought-tolerant sugar beet (Beta vulgaris L.) pollinator lines

Drought is among the most serious environmental stressors affecting sugar beet growth and productivity. The productivity of this crop can be improved by using tolerable genotypes against water scarcity. Therefore, the goal of the present study was to produce drought-tolerant pollinator lines with a cross between sugar beet and fodder beet and use them in the breeding program to develop sugar beet drought-tolerant hybrids. A separate population from sugar beet and fodder beet crosses was evaluated under several steps of drought conditions. In the first investigation, approximately 50 obtained half-sib families (HSF) were evaluated. The most tolerant family (110HSF-52) was chosen based on the selection index of ideal genotype (SIIG) and used for the production of new half-sib families. These families were later assessed under severe stress and the most tolerant family (110-52HSF-40) was selected based on SIIG. Seeds from this family were planted in the selected plot and 50 roots were selected for the production of S1 lines. Twenty S1 lines were evaluated under stress and non-stress conditions. Based on sugar yield under normal and drought stress conditions, different stress tolerance and susceptibility indices were estimated. Among the tolerant lines introduced by the mentioned indices, the S1950116 line with the highest value (0.66) of SIIG was introduced as the most tolerant pollinator line followed by S1950123, S1950119, S1-950077, and S1-950074 lines the SIIG values of 0.57, 0.56, 0.56, and 0.55, respectively. Based on the obtained results, it can be concluded that there is a source of drought-tolerant genes in fodder beet that can be used in the development of drought-tolerant sugar beet hybrids.