The 2012 ASHS Annual Conference

‘Zinner’ and ‘McMillan’ pecan cultivars have been evaluated for ten years in a yield trial located in south central Georgia.  Trial trees were planted in an irrigated orchard at a 12 m x 12 m spacing and given care according to UGA guidelines for commercial orchards.  Actual yields were measured for each tree.  A subsample of nuts was taken annually from each tree and nut weight, percent kernel, nut volume, and specific gravity were determined.  Cluster size, harvest date, and damage from pecan scab (Fusicladosporium effusum) and black pecan aphid (Melanocallis caryaefoliae) were also determined for each clone.  ‘Zinner’ had similar nut yield to ‘Desirable’ and ‘Stuart’ which were included in the trial as check cultivars.  Nut size of ‘Zinner’ (9.5 g) was slightly smaller than ‘Desirable’ (10.3 g) and very similar to ‘Stuart’ (9.7 g).  Percent kernel of ‘Zinner’ (57%) was superior to both ‘Desirable’ (52%) and ‘Stuart’ (45%).  ‘Zinner’ was susceptible to damage from black pecan aphids and will need to be monitored for this pest.  ‘McMillan’ had smaller nut size (9.1 g) and a moderate percent kernel (50 %), but much higher yields than ‘Desirable’ and ‘Stuart’.  ‘McMillan’ also had excellent resistance to pecan scab.  Both cultivars are now recommended for trial plantings in the state of Georgia, with ‘Zinner’ recommended for trial in full-spray commercial orchards and ‘McMillan’  recommended for low-input and organic plantings or in high scab pressure orchards.