We've each had 25+ year careers in plant breeding. It’s been fun, but we are excited to be
within 4 months of retirement. This will allow us to fully shift from working
for someone else to working for ourselves, and from breeding agronomic crops to
breeding fresh market tomatoes. Tomato
breeding started as a hobby about a decade ago and has grown into a passion. We are extremely fortunate to have found an
ideal partner that can handle the commercial side of our new business, and
allow us to focus on breeding. We will
continue to post here and a few other places as Frogsleap Farm, but our
products will be sold under the brand “Cream of the Crop Tomato” (link). We hope to have our first products on the
market next winter.
An earlier post on this site (link) was designed to provide
a high level overview on the use of molecular markers in tomato breeding. In 2015 we crossed our favorite FLF breeding
lines to various commercial F1 hybrids carrying resistance to multiple tomato
pathogens. We used molecular markers
associated with these disease resistance genes to identify segregating progeny
that contained the desired combination of these new traits. After 4-5 cycles (2-3 generations/yr) of Marker
Assisted Selection (MAS) we now have mostly stable lines which are homozygous
for some combination of the following resistance genes (and markers): tomato
mosaic virus (Tm2a), tomato spotted wilt virus (Sw5), tomato yellow leaf curl
virus (Ty1 and Ty3a), Verticillium wilt (Ve), Fusarium wilt (I1,I2 and I3),
late blight (Ph2 and Ph3) and leaf mold (Cf9). The project got legs this year with phenotypic
evaluation of 1000+ genotyped plants in our Wisconsin breeding nursery,
enabling us to combine selection for flavor and other fruit characteristics. We are continuing to integrate multiple
disease resistance into much of our heirloom-derived germplasm and will be
making crosses this year to produce new F1 hybrids with resistance to most of
these diseases.
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| Jess taking leaf samples for marker analysis |
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| 2017 Wisconsin Molecular Marker Nursery |
Septoria is a devil of a problem.
In our breeding nurseries in NC, PA and WI, Septoria is almost always
the most damaging disease, Like clockwork it starts on the bottom leaves about
early fruit set and then defoliates the plant from the ground up. There has
been no good source of resistance in commercial germplasm (yes, this includes
Iron Lady, the so-called tolerant/resistant hybrid from Cornell); but some
lines are worse than others. Over the
years we thought we found sources of some tolerance – but it wasn’t repeatable
the following year. This year we found
two lines with significantly less damage than the nearest neighbors, and for
both this was the second such observation in consecutive years. Both 2016 and 2017 were wet in the Midwest,
we didn’t apply fungicides, and Septoria was rampant with extensive associated
plant symptoms. One of our new
“tolerant” lines traces to a cross to a S. pimpinellifolium accession I got
from Dar Jones, and tolerance looks excellent.
We will have these in broader testing next year.
For several years we have been evaluating segregating
progeny from heirloom beefsteak x cherry/saladette crosses. In successive filial generations and cycles
of selection (phenotypic recurrent selection) we have focused on large fruit
size, excellent fruit quality and great flavor.
We are finally getting stable large fruited segregants in various colors
– most with excellent flavor and great fruit quality. This
winter we will start making test crosses with these new breeding lines and
begin the process of incorporating multiple disease resistance genes.
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| Three beefsteak segregates from cherry x beef crosses |
This summer we had a very generous invitation to visit Japan
and learn about their commercial tomato production system and current and
future variety needs. It is
predominantly high input seasonal greenhouse production of cherry and grape
types, the hybrids having a particular plant architecture and disease
resistance profile. It knocked our socks
off. We now have a segment of our
breeding program targeting such products, starting with our crosses to
commercial Japanese hybrids and progressing to MAS selected F2 progeny being
planted this month in a greenhouse for the next cycle.
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| Learning the basics on their trellis system |
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| A variety of farm produced juices from Japan |
