Empyrean® 1 is a peach hybrid with extraordinary vigor. This rootstock has a lower chilling requirement than Hansen 536, making it useful in low chill conditions sometimes experienced in California. Bloom timing is similar to the common Nemaguard rootstock, while harvest timing is similar to Hansen 536. The vigor of Empyrean® 1 results in quick space-filling and rapid increases in production. In young trees, high almond production has not sacrificed nut size. Empyrean® 1 shows promise of being one of the best and highest yielding almond rootstocks available for well-drained soils.
PARENTAGE: Prunus persica x Prunus davidiana
ORIGIN: CNR, Italy
OLDEST TEST SITES IN THE US: 2003 with Peaches in western Colorado, 2004 with almonds in the San Joaquin Valley.
COMPATIBILITY: Almonds, some plums (European and Japanese), peaches and some apricots.
VIGOR: Approximately 120% the vigor of Nemaguard and 110% the vigor of Hansen 536 with almond scions.
GROWTH UNIFORMITY: Good with almond.
ROOTSTOCK INDUCED TREE FORM: Slightly more spreading than Nemaguard.
ANCHORAGE: Superior to Nemaguard. Tests are continuing.
YIELD EFFICIENCY: Excellent with almonds in the early years. Tests are continuing.
SUCKERING: Does not produce suckers.
CHILLING REQUIREMENT: Lower chilling requirement than Hansen 536.
COLD HARDINESS: Has not been well tested. No problems have appeared in a western Colorado test site.
NEMATODE RESISTANCE: Resistant to Rootknot nematode. Tests are ongoing for Ring nematodes. Not resistant to Lesion nematodes.
EFFECT OF ROOTSTOCK ON BACTERIAL CANKER SUSCEPTIBILITY: Unknown.
OAK ROOT FUNGUS TOLERANCE: Untested.
PHYTOPHTHORA SENSITIVITY: Appears similar to Nemaguard, but needs more testing.
VERTICILLIUM RESISTANCE: Slightly susceptible, but much less than Lovell rootstock.
DISEASE PROBLEMS--OTHER: Unknown.
ASPHIXIA TOLERANCE: Unknown
DROUGHT TOLERANCE: Unknown
CROWN GALL SUSCEPTIBILITY: Susceptible. Level of susceptibility is not extreme, but needs more evaluation to determine the level of susceptibility experienced in orchards.
HIGH pH TOLERANCE: Moderate.
SALT TOLERANCE: Good. Performs better than many Peach-Almond hybrids
CALCAREOUS SOIL TOLERANCE: Moderate.
REJECTION COMPONENT OF REPLANT DISORDER SUSCEPTIBILITY: Good. Similar to Hansen 536