Identification of souitable female parent for developing resistant sugar beet varieties to major soil borne diseases

In order to understand the role of maternal parent in producing sugar beet cultivars resistant to rhizomania, root rot, and beet cyst nematode diseases, 12 single crosses resistant to rhizomania, three normal single crosses, and two male sterile lines were crossed with two pollinators. One of the pollinators (SB36-S1-3) was resistant to beet cyst nematode and the other one (33345-93) was resistant to rhizomania and root rot. The presence of rhizomania and cystic nematode resistance gene in parents and hybrids was determined. Hybrids were evaluated in two trials of 20 (hybrids resistant to rhizomania and beet cyst nematode) and 16 cultivars (hybrids resistant to root rot and rhizomania) in five locations including Shiraz, Ghazvin, Mashhad, Torbat-e-Jam and Hamadan. In 20 cultivars trial, hybrid (201-25*301-28) *SB26-S1-3 with the presence of 35% MN gene and 100% Rz1 gene as well as 6.53 t/ha white sugar yield (equivalent to 149% of Arya) was selected as the superior hybrid. In this trial, foreign control cultivars namely Toucan and Succara produced 5.85 and 8.08 t/ha white sugar yield, respectively. In 16 cultivars trial, hybrid (201-25*301-28) *33345-93 with 132% of the control cultivar Ekbatan in terms of white sugar yield (4.72 t/ha) was the superior hybrid. This hybrid lost 10% of its individual plants during the growing season because of root rot. Under this condition, Ekbatan, Boomerang, Perimeir, Novodoro, and Sharif cultivars lost 12, 7, 12, 4 and 28 % of their plants during the growing season, respectively. Hybrid (201-25*301-28) *33345-93 produced 6.23 t/ha white sugar yield which was more than Novodoro (5.55 t/ha), Boomerang (5.52 t/ha) and Perimeir (3.97 t/ha). Single cross 201-25*301-28 with 90% presence of Rz1 gene, virus concentration of BNYVV in a level of Brigita, resistant foreign control, and producing highest sugar yield in crosses with both of pollinators was introduced as a superior maternal parent for new hybrid production.