Submitted to: Journal of American Pomological Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2003
Publication Date: 1/5/2004
Citation: Beckman, T.G. 2004. Modifying bloom and harvest date of peach with interstems and rootstocks. Journal of American Pomological Society. 58:12-20. Interpretive Summary: Spring freeze injury is a major factor limiting peach production in the southeastern United States. A variety of chemicals, oils, and management practices have been shown to modify bloom date. Recent work has identified several interstems and rootstocks which are capable of modifying bloom date significantly. In this trial we compared typical 2 piece trees of Springcrest and Harvester on Lovell rootstock with 3-piece trees with a Ta Tao #6 interstem inserted between the fruiting variety and the Lovell rootstock. Over the 4 cropping years observed, the Ta Tao #6 interstem trees provided a significant bloom delay of slightly more than 6 days on average. In 2 of the 4 cropping years significant freeze events occurred during bloom and in one of these events the Ta Tao #6 interstem trees provided a significantly larger crop compared to their earlier blooming 2-piece counterparts. Otherwise there was no difference in the cropping efficiency of the 3-piece trees compared to their 2-piece counterparts. Results indicate that Ta Tao #6 interstems will reliably delay spring bloom of peach varieties. However, the utility of this effect will depend upon the timing of late Spring freeze events relative to bloom date. Exceptional events, such as occurred in 1996 still defeated this approach. In addition, the Ta Tao #6 interstem trees displayed a delay in fruit maturity averaging 3.6 days over all cropping seasons. This influence may prove useful in extending the usable season of preferred varieties.
Technical Abstract: Avoidance of spring freeze injury through bloom delay can provide more consistent cropping in years when late spring frost damages flowers or young fruit. In this study, a Ta Tao #6 interstem significantly retarded bloom of Springcrest and Harvester peach, averaging slightly more than 6 days delay. Significant freeze events occurred in two of the four cropping years observed. However, the bloom delay provided by a Ta Tao #6 interstem was sufficient in only one of these events to significantly improve fruit yield. Attempts to close a gap between Harvester and Redglobe peach varieties by altering fruit maturation were only partially successful. Fruit maturation of Ta Tao #6 interstem trees was delayed on average 3.6 days over the 3 cropping seasons observed when compared to that of their 2-piece counterparts on Lovell seedling rootstock without the interstem. However, 2-piece trees on Halford seedling rootstock failed to advance maturation compared to the Lovell rootstock and the net shift in the harvest window of Harvester peach was insufficient to close the 11-12 day gap observed. Nevertheless, the use of Ta Tao interstems to delay bloom and fruit maturation offers growers a useful tool to manage their spring frost risk and harvest management.