This Is AuburnElectronic Theses and Dissertations

Performance of pecan (Carya illinoinensis) cultivars grown in Alabama




Warren, Thomas

Type of Degree

PhD Dissertation




Between 1996 and 1999, pecan cultivars were grafted to mature pecan trees at the E.V. Smith Research Center in Shorter, Alabama [E.V. Smith] and Gulf Coast Research and Extension Center in Foley, Alabama [Gulf Coast] in either a low or high input environment. High input orchards received irrigation and pesticide, herbicide, fungicide, and fertilizer treatments. Low input orchards received an initial fertilizer treatment based on soil test recommendations and no irrigation or chemical treatments. From 2010 to 2013, nuts from each graft were collected on an annual basis. Data collected for each cultivar included: nut grade, percent kernel, total yield, pounds of nuts per cultivar, leaf retention, and percentage of nut scab, shuck split and leaf scab. Additionally, in the fall of 2014, nuts from ‘Desirable’, ‘Elliott’, ‘Gafford’, ‘McMillan’, and ‘Syrup Mill’ cultivars were collected for total triglyceride and fatty acid profiles. The cultivar ‘Desirable’ was set as the control due to its established high quality and long term presence within the industry. In the high input orchard at E.V. Smith orchard, seven cultivars had more No. 1 pecans than ‘Desirable’. Additionally, ‘Desirable’ had more foliage scab, stem scab, and nut scab than all other cultivars. There was no difference in foliage retention rate among cultivars in the highinput orchard. In the high input orchard at Gulf Coast, ‘Sioux’ had more No. 1 pecans than ‘Desirable’. iii In the low input orchard at E.V. Smith, nine cultivars all had more No. 1 nuts than ‘Desirable’. Every cultivar except ‘Staten’ had less leaf scab and less stem scab than ‘Desirable’. Several cultivars exhibited greater foliage retention than ‘Desirable’. In the low input orchard at Gulf Coast, 10 cultivars had a difference when compared with ‘Desirable’. In both low input orchards, ‘Desirable’ did not perform as well as other cultivars. Several cultivars had more No. 1 nuts, higher percent kernel, and fewer rejects than ‘Desirable’. Regardless of input environment, ‘Desirable’ had the highest total lipid weight of all cultivars in the fatty acid analysis. ‘Syrup Mill’ had the lowest total lipid weight of all cultivars. These findings suggest that although ‘Desirable’ performs well in a high input environment, it does not perform well in a low input environment and other cultivars are more suitable for a low input orchard.