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

For development of pollinator parent resistant to powdery mildew disease of sugar beet، relatively resistant 14442 population was used. Based on resistance index، 50 resisitant plants were selected to produce half sib family (H. S. F). After random pollination between these 50 plants، seed of H. S. F was harvesed. From these 50 plants، only 39 plants had produced enough seed. Next year these H. S. F were planted in one raw plots with six replications and evaluated for disease resistance. After evaluation، 3 H. S. Fs (H. S. F13، H. S. F24 and H. S. F35) with high level of resistance were selected. From those 3 families، 150 roots were selected to produce new half sib families (N. H. S. F). Between these 150 families only 88 roots produced enough seed. In the next cycle، 88 N. H. S. F were evaluated for disease resistance and 3 N. H. S. F (H. S. F5، H. S. F17 and H. S. F22) with high level of resistance were selected. From each N. H. S. F، 35 roots were selected to produces. In the cage، from 105 roots only 13 plants produced enough seed. In the next year 13، S1 again evaluated again for disease resistance. Low level of infection (12. 9 %) was observed in the S1 lines. Therefore، selection in the 14442 population for powdery mildew resistance was very effective، and plants selected in this method showed 72. 6 % selection progress. Because of the good resisitance of the S1 lines، they could be used to develop powdery mildew resistance varieties.