Transfer of powdery mildew erysiphe cichoracearum resistance from helianthus debilis to cultivated sunflower helianthus annuus
Jan, C.C.; Chandler, J.M.
Crop Science 25(4): 664-666
Powdery mildew of sunflower is a disease which can have a serious economic impact when the crop is grown in warmer regions. An accession of H. debilis ssp. debilis Nutt. (2n = 34) found to be highly resistant to sunflower powdery mildew at Davis, CA [California, USA] was used in a program to transfer resistance to the cultivated sunflower, H. annuus L. (2n = 34). Plants of the wild accession were pollinated by the susceptible H. annuus cv. Peredovik and line P21. The F1 plants were backcrossed once with P21 and the BC1F1 plants were self-pollinated, sib-pollinated, or further backcrossed with P21. Disease evaluations on all tested plants were conducted in a greenhouse under cool temperature and high humidity using previously infected, susceptible plants as the source of inoculum. Infection was measured as the percent of leaf surface covered by mildew. The mean infection percentages of P21, the F1 and H. debilis were 100, 15 and 0, respectively. Resistance was incompletely dominant in the F1 and backcross progenies. This source of disease resistance may enable the production of resistant hybrid cultivars suitable for warmer regions.