EVALUATION OF POTENTIAL ROOTSTOCKS FOR CALIFORNIA ALMONDS

Four Regional Rootstock Trials are underway in Butte, Colusa, Kern, and San Joaquin counties.
Colusa and Kern county trials were planted in 1997 while Butte and San Joaquin county plantings occurred in 1998. Evaluating rootstock potential for better anchorage, bacterial canker resistance, and tolerance to shallow soils and high rainfall environments will be useful in adapting orchards to the diverse environments where California almonds are grown.
In addition, the four trials are evaluating rootstock influence on growth, yield, and tree survival.
Initial tree mortality was highest on ‘Viking’, followed by ‘Atlas’ possibly due to sensitivity to drying during cold storage or planting.
Mortality of trees on all other rootstocks was commercially acceptable.
Trees on ‘Hansen 2168’, ‘Hansen 536’, and ‘Nickels’ (UC 1-82) were frequently larger in trunk circumference than trees on the other rootstocks.
Tree height measurements made following the second, third, or fourth growing seasons showed some differences between rootstocks.
Trees on ‘Hansen 536’ or ‘Hansen 2168’ were taller than trees on other rootstocks while trees on ‘Bright’s’ hybrid, ‘Viking’, and ‘Nemaguard’ were often shorter than trees on other stocks.
Initial harvests in the third and fourth growing seasons found that yields on ‘Atlas’ were often significantly greater than the yield on other rootstocks.
Early in the fourth growing season in the Butte County trial substantial tree losses occurred during a windstorm especially on ‘Hansen 536’ but trees were also lost on ‘Nemaguard’, ‘Bright’s’ and ‘Atlas’ rootstocks.
We will continue to develop additional information as these orchards mature.

III International Symposium on Pistachios and Almonds

J.H. Connell, R. Buchner, R. Duncan, J. Edstrom, W. Micke, P. Verdegaal, M. Viveros

Prunus amygdalus Batsch, [Prunus dulcis (Mill.) D.A. Webb], hybrid, yield, mortality, growth.

https://doi.org/10.17660/ActaHortic.2002.591.2