Growth Characteristics of Selected Pecan Rootstocks Prior to Grafting

Abstract

Six pecan ( Carya illinoinensis(Wangenh.) K. Koch) cultivars and five pecan families (closely related individuals from a native stand, seed from at least 10 native trees were pooled) were evaluated for use as rootstocks. The evaluation period was from seed planting through 4-years-old, but before the rootstocks were grafted. ‘Apache’ rootstocks grew more rapidly than the other rootstocks tested during the first two years. However, by the fourth year ‘Apache’ and ‘Peruque’ trees were similar in height, and trunk diameters of ‘Apache,’ ‘Giles’ and ‘Peruque’ were not significantly different. Coefficients of variation for tree heights and trunk diameters indicated that variability between individuals was similar within most cultivars and families. Budbreak date was strongly influenced by rootstock source, with up to a 14 day difference between the first and last rootstocks to attain 90% budbreak. An April freeze damaged current season's growth on 90% of the ‘Apache’ trees, but only 10% of the ‘Giles,’ ‘Starking Hardy Giant,’ and natives from Chetopa, KS and Sapulpa, OK were injured. Freeze damage was dependent on the bud developmental stage. Several significant differences in leaf elemental concentrations between rootstocks were identified.