Submitted to: International Symposium on Pistachios and Almonds
Publication Type: Abstract Only
Publication Acceptance Date: 4/2/2008
Publication Date: N/A
Technical Abstract: Peach-almond hybrids are becoming increasingly popular rootstocks in California almond orchards due to their enhanced vigor as compared with almond propagated on peach root. However, these hybrids are difficult to root without the use of in vitro micropropagation. The development of uniform and vigorous seed-propagated peach-almonds would be a major benefit to commercial almond nurseries in California, which rely heavily on seed propagation. Breeding efforts in central California have yielded several seed-propagated rootstock selections that are suitable for use as almond rootstocks. Root architecture of these potential new rootstocks resembles that of almond, providing enhanced tree anchorage as compared to peach root. Male-sterility has been incorporated into the peach-almond mother trees to force hybrid seed production from selected root knot nematode resistant pollenizers. Male-sterile mother trees and their potential pollenizers were examined over a six year period to identify those most synchronous in bloom periods. While seedling emergence of several peach-almond hybrid seedlots did not differ from that of Nemaguard under field conditions, improved emergence levels would benefit nurseries using these rootstocks in commercial tree production. We are currently evaluating the effects of pre-plant stratification and imbibition treatments as a means of increasing seedling emergence to levels acceptable with commercial nurseries.