Field Performance of Guardian™ Peach Rootstock Selections

Abstract

Twelve peach [Prunus persica (L.) Batsch] seedling rootstocks [Lovell, Nemaguard, Flordaguard, 14DR51, five Guardian™ (BY520-9) selections, and three BY520-8 selections] budded with `Cresthaven' were planted in 1994 and evaluated through 2000 to determine performance under commercial management practices. Mesocriconema xenoplax population densities were above the South Carolina nematicide treatment threshold of 50 nematodes/100 cm3 of soil after 1996. However, symptoms of peach tree short life (PTSL) were not observed. Tree mortality was less than 14% through 1999, with most of the dead trees exhibiting symptoms consistent with Armillaria root rot. About 13% of the surviving trees in 1999 were removed in 2000 due to symptoms of phony peach. There were no differences in tree mortality among rootstocks. Tree growth, photosynthesis, and suckering varied among rootstocks, but leaf conductance, internal CO2, and leaf transpiration did not. Foliar calcium, magnesium, iron, and phosphorus varied among rootstocks, but all were within the range considered sufficient for peach trees. Fruit yield varied among rootstocks, but yield efficiency did not, indicating that higher yield corresponded with larger trees. Bloom date did not vary among rootstocks, but harvest date was advanced as much as 2 days for some rootstocks, compared to Lovell. Fruit weight varied among rootstocks but skin color, flesh firmness, and soluble solids content were similar. All rootstocks performed satisfactorily for commercial peach production.