'Theta', tested as OSU 1001.008, resulted from a cross of OSU 561.184 × 'Delta'. The controlled crosses were made by S.A. Mehlenbacher and D.C. Smith in 1999.

Tree Vigor and Growth Habit

'Theta' will produce trees that are 100% of Barcelona. 'Theta' trees have a more upright growth habit.

Disease Resistance

'Theta' has a high resistance to Eastern Filbert blight.

Nursery Habit

'Theta' roots abundantly from layer beds similar to 'Jefferson'. Rooted layers of 'Eta' are moderately vigorous, whereas those of 'Theta' are vigorous and similar in height and caliper to those of 'Barcelona'. It can also be produced from TC, Soft Wood Cuttings, and Suckering tie-off.

Horticultural Value

'Theta' is not promising as a main crop variety because of small nut size and late maturity. 'Theta' provides excellent coverage late in the flowering season when little pollen is available from other pollenizers and cultivars. 'Theta' is a suitable pollinizer for 'Jefferson', 'Clark', 'Ennis', and 'Casina'.