Old and Young Variety Test at UGA Tifton
The Old Variety Test was established in 1921 early in the history of the Coastal Plain Experiment Station by Dr. O.J. Woodard. The Young Variety Test was established in an adjacent area in 1955. Most of the data presented was collected by Dr. Ray Worley and was originally published here: (Worley and Mullinix, 1997). Trees were planted in a 40' x 40' spacing and have been selectively limb pruned to remain at this spacing.
Records are not available on fertilizer rates and other cultural practices utilized during the early years of the test, but apparently the best production practices known at the time were used. Trees were sprayed with insecticides beginning in 1962 and fungicides beginning in 1970, using Extension service recommendations and scouting for insects. Insecticides were applied only when an insect buildup occurred.
Since 1962, trees have received 100 pounds N/acre/year as ammonium nitrate and other nutrients and lime when leaf analysis or soil analysis indicated need. Drip irrigation has been provided through six 1 gal/hour emitters/tree since the fall of 1974. Irrigation water was applied when the matric potential reached -.1 bar.
Selective limb pruning has been practiced annually in the older orchards since 1974-75. This procedure molds and holds the trees within the allotted space by removing one to three limbs back to another limb, not leaving a stub and topping at 30 feet.
Total yield per tree was obtained by harvesting each tree independent of other trees by hand or by a Lockwood harvester. A 50-nut sample was collected from each tree for quality analysis beginning in 1969. Kernels were graded into fancy, standard, and amber grades. Percentage of each size, kernel grade, total percentage edible kernel, specific gravity, were calculated.
Fancy kernels were plump, well-filled kernels of the brightest color. Standard kernels were similar but darker. Amber kernels were darker than standard kernels and/or had edible kernels with defects. The standard grade corresponds to Goldkist's "special" grade. Goldkist's color chart was used in grading kernel color. The percentages of the various kernel grades are percentages of the in-shell nut. Nut volume and percentage fill were determined by water displacement. Percentage fill is the percentage of the volume inside the shell that is filled with kernel. Total percentage kernel is the sum of fancy, standard, and amber for a particular tree in a year. (The overall averages of individual grades may not add up to the overall average percentage kernel because of year-to-year variation and rounding.)