Crown depth and susceptibility to crown rot in wheat

Sources of partial resistance to crown rot caused by Fusarium pseudograminearum are detected in mature plants grown in artificially inoculated soil in the field. The resistance in most but not all of these sources can also be detected in seedlings. In order to determine whether partial resistance is related to depth of crown formation, this character was measured in 13 cultivars/lines with a range of reaction to crown rot. It was also measured in doubled haploid plants from the cross, Batavia/2–49. Crown depths varied from 17.1 mm to -2.3 mm (above ground) in pots in a waterbath at 25 °C and from 43.5 mm to 20.7 mm when plants were grown in the field. The correlation coefficient between relative susceptibility to crown rot (Field test) and crown depth of 13 cultivars/lines was 0.57 (p ≤ 0.05). With the exception of the cultivars, Sunco and Pelsart, partial resistance to crown rot was inversely related to depth of crown formation. This indicates that depth of crown formation may be partly responsible for the reaction of a cultivar/line to crown rot. Depth of crown formation was also measured in susceptible and partially resistant cultivars/lines grown from seed planted at different depths. As depth of seeding increased, depth of crown formation in partially resistant and susceptible cultivars/lines increased in similar proportions.