Below are results from the harvest of the Owari rootstock trial in the fall of 2021.  I added the 2019 & 2020 yields for a comparison. 2021 was the biggest yielding year to date with 20,301 lbs of fruit harvested from 60 trees. Converting our plot size to an acre would have yielded 60,903 lbs of fruit. Trees on Rubidoux had a severe alternate bearing year and had virtually no fruit. There was not enough fruit to test the juice. Owari on X-639 rootstock had the highest yield in 2021 with 571 pounds per tree, and they are also are the largest trees.  In general, the largest trees had the most fruit in 2021.  X-639 also had the lowest average Brix value. What I have observed the past two years is that the fruit on the highest yielding trees was less firm and slower to color than fruit on trees with more moderate yields. If this trend continues it may be that rootstocks that have more consistent yield may be a better choice than larger yielding rootstocks. From bloom observations this spring it appears the high yielding trees of 2021 will have another off year while lesser yielding trees last year look to have more fruit to this point.  So it appears that rootstocks that yield big one year will have a more severe off year the following year. 

RootstockPlanting DateBrixAcidRatioAvg. Fruit Weight (g)Yield in 2019 (lbs)Yield in 2020 (lbs)Yield in 2021 (lbs)Canopy Volume (cu ft.)
X-6398/20149.20.826711.2129187157571418
Kuharski8/201410.00.845011.9136181146508376
Cleopatra8/20149.90.889911.113713378488406
US-8128/2014100.928310.9130146202463329
Swingle8/20149.80.900210.914297158386302
US-8525/201510.70.922911.6153102217278252
Sour Orange7/201510.30.831112.51396640264236
US-9428/201410.20.917611.1156147306233260
US-8978/201510.50.992610.717470207149181
Rubidoux6/2016NaNaNaNaNa1042.292