Effect of Sowing Time on Development of Safflower Anthracnose Disease and Degree of Resistance in Various Cultivars.

Field experiments were conducted under natural as well as under vinyl house conditions to determine the effect of sowing time on development of anthracnose of safflower caused byColletotrichum acutatum, and to determine the level of resistance of seven cultivars. When crops were sown from March 1 to April 1; safflower anthracnose disease (SAD) incidence was low and increased slowly (0.7–10.9%) throughout the growing season. When sowing was delayed to April 15, disease incidence ranged between 29.5 and 48.5% from late May to July. Similarly, SAD severity and its severity index were higher (3.5 and 3.3, respectively) in plots sown on April 15 than in the plots sown from March 1 to April 1 (1.9–2.4 and 1.8–2.2, respectively). In contrast under vinyl houses that sheltered from rain, sowing time did not affect neither SAD, nor severity and severity index, which were 5.7–6.4%, 1.5–1.7 and 1.5–1.7, respectively. Among seven cultivars tested for resistance to SAD, Uisong-1, China-2 and India were highly susceptible (80–97%) under natural conditions followed by China-1, Uisan, Uisong-7 and Cheongsu (27–35%); however, under vinyl house conditions, SAD was lower (5.7–8.2%) and there was no significant difference between cultivars. [ABSTRACT FROM AUTHOR]