Variation in dormancy, seed germination and aggressiveness of field dodder (Cuscuta campestris Y.) ecotypes in sugar beet

In this study, 10 ecotypes of field dodder (Cuscuta campestris Y.) collected from infected sugar beet fields in Ardabil, West Azerbaijan, Qazvin, Khorasan Razavi and Alborz provinces were evaluated for germination rate and percentage. The effects of seed storage duration and scarification with sulfuric acid 98% on seed dormancy and germination characteristics of the ecotypes were studied in the growth chamber and their ability to infect sugar beet was studied in the greenhouse. Experiments were carried out in completely randomized design with four and three replications in the growth chamber and greenhouse, respectively. Significant difference (p ≤0.01) was observed among the ecotypes for all studied traits. The minimum and maximum germination percentage of the ecotypes before sulfuric acid treatment was 3 and 29%, and after treatment reached to 13 and 87%, respectively. The highest impact of acid treatment was observed in the ecotype collected from Parsabad, Moghan. The ecotype collected from Jahanabad, Qazvin, showed negative response to acid treatment and its germination decreased. Seed storage for one year did not influence the seed dormancy break. There was significant difference (p ≤0.01) among the ecotypes for seedling length, fresh and dry weight of 1000-germ (1000-seedling). The minimum seedling length (3.2 cm) and dry weight of 1000-germ (0.09g) was observed in Jahanabad ecotype. The ecotypes were also significantly different (p ≤0.01) for aggressiveness and infection. Ecotypes collected from Urmia and Meshkindasht of Alborz had the maximum and minimum aggressiveness, respectively. Although, the biological behavior of the parasitic dodder weed did not follow a constant pattern, identification of their biological characteristics can be useful in the progress of management programs to control the weed.