|Authors: ||G. Reighard, D.R. Ouellette|
|Keywords: ||Prunus persica L., phenology delay, Peach Latent Mosaic Viroid, suture warts|
An orchard (4.3 ha) of one-year-old ‘Redglobe’ peach trees on ‘Guardian®’ rootstock was inoculated with a strain of Peach Latent Mosaic Viroid (PLMVd) by chip budding with vegetative buds taken from PLMVd-infected ‘Ta Tao 5’ peach trees in September 2003. Trees were spaced 3.7 m (+PLMVd), 4.3 m (+PLMVd), or 4.9 m
(-PLMVd) within rows that were 6.1 m apart with each plot consisting of 6 orchard rows.
There were 2 replications.
Trees were trained to an open-center system and were located near Ridge Spring, South Carolina.
Data collection included time to summer prune and dormant prune trees, time to hand thin immature fruit, ripening date, harvest period, fruit yield, fruit size, and fruit quality for some or all of the years of 2006, 2008, 2009, 2010, 2011, 2012 and 2013.
PLMVd-inoculated trees bloomed 5-14 days later, and took less time to dormant prune viroid-free control trees. Time to hand thin viroid-infected trees was significantly more (2 min/tree) than controls in 2008 due to excessive buttons and doubles, but took 6, 5, and 2.5 min/tree less in 2009, 2010 and 2011, respectively.
PLMVd delayed ripening 5-14 days, and total length of the harvest period including controls ranged from 16-26 days.
Yields per hectare from PLMVd trees declined from 116% of control yields in 2006 to 68 and 42 percent in 2008 and 2009, respectively, years where weather prolonged bloom 13-14 days.
PLMVd trees did yield 4% and 1% better, though statistically non-significant, in 2010 and 2011, respectively.
There was no commercial crop on PLMVd trees in 2012 due to fruit buttoning from a low chilling winter and/or high bloom temperatures (>29°C). Peak harvest dates in 2008, 2009, 2010 and 2011 for PLMVd trees were 7, 9, 4 and 9 days later, respectively.
Fruit size was smaller from PLMVd trees in 2006 and 2010, but larger in 2008, 2009 and 2011. Fruit from PLMVd trees had similar soluble solids as the controls but had significantly higher titrated acidity and were firmer.
In some years peach warts, which are symptoms of peach viroids, were common on the fruit sutures of viroid-infected fruit.
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