May 2022 - 11

at bloom and after bloom. Therefore, we
could not evaluate how well FruitScout
estimated cluster counts or cluster density.
The way I did it was probably not a fair
comparison. "
Marini measured fruit size on
Honeycrisp, using the same 15 trees, 10
fruit per tree.
" FruitScout overestimated average
fruit diameter, " Marini said. " In fact, it
underestimated size of the big fruit and
overestimated the size of the small fruit.
There's a problem here. It's not estimated
fruit size the way I would expect. We
saw the same type of things for Fuji. The
estimates are bigger than the diameter.
We would conclude that the diameters
(comparisons) are different.
" FruitScout underestimated the size
of the big fruit, and overestimated the
size of the small fruit, " Marini said. " The
distribution measurement was different
from a statistical point of view. "
Marini said FruitScout was effective
in measuring the trunk cross-sectional
area (TCSA), but " tended to overestimate
the fruit diameter. There are a couple
of reasons. Fruit are not symmetrical.
Especially Fuji, it can be sort of oblique.
" It's also important to get a sampling of
fruit that truly represents the population
on the tree, " Marini said. " I've tried this a lot
of different ways over the last 30 years. You
basically have to sample 25% of the tree
to get a good estimate. Mark only looked
at 7% to 9% of the tree, and I think that is
part of the problem. "
" FruitScout is an evolving machine. It's
not going anywhere, " Marini concluded.
" We're going to need technology like this if
we want to stretch that dollar out. "
FruitScout upgrades set
Matt King, CEO and founder of
FruitScout, who sat in on the presentation
by Boyer and Marini, pointed to
improvements to FruitScout's service, and
responded to the findings by the speakers.
" Mark was dead on, " King said. " Last
year, in the first year of operation, we were
too slow getting reports back. That was
due to a lack of structure. We've really
addressed that problem now. We guarantee
to get reports back to you the next day.
" In terms of size measurements, both of
those algorithms are the same thing, " King
said. " It's the same system measuring trunk
size and fruit size. I'm morally obligated to
agree with Dr. Marini, but I don't think the
size calibrations that we were doing were
apples to apples comparisons. Those were
literally different apples.
" The big thing I'd like to point out is
that with our fruitlet growth models, you
no longer have to mark back to the same
fruitlets, " King said. " We've taken the work
out of that. You just need to go take a
picture and size four to five fruitlets, come
back four to five heat days later, take four
or five new pictures and not necessarily the
same ones. We've taken that work down to
a couple of hours instead of 10 or 20 hours.
" You have to accept that there is
a difference between commercial
instrumentation and research
instrumentation. There's always going to
be, " King said. " The question is, when is
there enough information so the grower
can make a decision, and what is that
information worth. " FGN
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May 2022

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