Development of diploid pollinator for resistance to powdery mildew disease in sugar beet

Abstract

To develop pollinator parent resistant to powdery mildew disease, a semi- resistant population, 14442, was used. In the first year of the experiment, fifty resistant single plants were selected based on resistance index, and the seeds of half-sib families were produced. Among the 50 plants, only 39 plants produced enough seed. Harvested seeds were planted in one-row plots, replicated six times, and were evaluated for resistance to powdery mildew. Three out of the 39 half-sib families (HS.13, HS.24 and HS.35) with a lower infection (<2.5) were selected. From each of the three families, 50 plants were selected and then planted in isolated tents to develop new half-sib families. In total, 88 new half-sib families were developed. The seeds of the new families were planted in single-row plots replicated six times and were evaluated again. Among them, the half-sibs numbered 5, 17 and 22 were found to be resistant to disease compared with the other progenies. From each half-sib, 35 roots (105 roots in total) were selected for S1 production. Each of the roots was divided to four parts (clone), and cultured in an isolated cage to produce S1 seeds. Owing to the problems occurred in isolated cage, from 105 selected roots, only 13 roots could produce enough seed with good viability. Thirteen self pollinated seeds/S1 (new germplasm), were evaluated for powdery mildew resistance. Results illustrated that in each generation of selection, resistance increased with positive responses. The minimum percentage of infection (12.9) was observed in S1 plants. S1 population showed 72.6% selection response compared with first population of 14442. Due to the good resistance of S1 plants, they could be used as pollinator for producing cultivars resistant to powdery mildew disease.

Keywords

• pollinator
• powdery mildew
• resistant
• sugar beet