Why Hybrids, Chestmutts
John Gordon, [email protected]
www.geocities.com/nuttreegordon/0Kxhsmut.htm
This was to be a paper to accompany my show
and tell of a bag of chestnuts from my farm,
AKA research farm. Hybrid chestnuts are like
dogs, mutts, mongrels. They are not like our
cats. Cats look like each other. Dogs are weird.
Chestnuts are weird.
We have crossed three species of chestnut
(Japanese, Chinese, American) to gain all these
mutts. We is 'a northern we', and our breeding
material is the 'northern sorts in these species'.
Korean and European were left off the list
because we have made all the mutts in my bag
without resorting to them.
(Here comes dispute.) Korean is widely known
as a cross between Chinese and Japanese.
Actually it is not. Cliff England has done
research in Korea which gave him ample time to
become familiar with Korean chestnut. " The
'original Korean' was out of Manchuria and
Siberia. It is a northern Chinese which still
exists in Korean and Manchurian forests." I
looked for the land bridge which led the Korean
to Japan. None existed, but a land bridge did
link Siberia with Japan from the north for
geologic periods earlier than the Pleistocene
Period, the ice ages. Suddenly a light comes on
why Japanese is so different from Chinese. It is
an ancient separation of these species. "
Recently there has been a lot of crossing of
Japanese and the 'original Korean'. This is
recorded in old tombs and texts." Observing
genetic DNA for variation leads to the same
conclusion, or I thought Dr. Sandra
Anagnostakis was confirming this when she
sprung it about the different genetics of several
Korean varieties ("EXCEPTION of Pochun B-1
gou and Buyu3 gou which are quite different
from the other tested Korean chestnuts and
from mollissima"). Ouch, bit in the butt by more
mutts.
And so it goes with 'Marrone European'. The
original European cross with Oriental (Chinese,
Japanese, their hybrid, or southern species of
Chinese) was make and recorded in the history
of the silk road from China to become the
Marrone. The Marrone European which we see
in stores around Christmas time is this cross.
American and the original European separated
when Newfoundland separated from Scotland.
Yet the American-like trees remain, and are
scattered over northern England and northern
Europe. These trees are so close to native
American that the guys with the microscopes
are continually classifying turgid upland
American chestnut leaves as from European
hybrids, and visitors to the estates in northern
England assume their chestnut trees are
American.
Go figure... Even if we got the recent history of
the Korean and European wrong, and remember
we are never wrong, we are trying for better
forms of Koreans, and Marrones. Access to the
most hardy and resistant Marrones and Koreans
should save us time selecting through
generations of Japanese hybrids for pleasant and
fixed traits. Maybe not, because we are well
into constructing American Korean and
Marrone American types from the more basic
crosses, and better yet, the breeding of more
intrepid growers of Korean and Marrone has
already crossed Marrone, Korean, Chinese,
Japanese, and American. Today
Marrone-crossing actually adds to our breeding
time because these precociously large size
European nuts, which southern Europeans
sought and gained, ruined winter hardiness
needed in our fluctuating northern climate. Ever
the "large chestnut" breeder, Ernie Grimo is
crossing Swiss #5353 and Connecticut's
Japanese x American hybrids. Connecticut's
Japanese x American hybrids are genetically
most like Pochun B-1 gou and Buyu 3 gou, as
mentioned above as the "quite different
Korean". If Ernie could grow out and stress the
nut wonders he produces he would extend up
into Ontario commercial chestnut growing.
'Recent Korean' adds hardiness, and the blight resistances of Chinese to Japanese. This cross has already put the tiny buds of Japanese on Chinese for gall wasp resistance.
Traits we see in Japanese:
1) Blight resistance which is equal, but different
from Chinese.
2) Able to set top bud in a cool, short season.
3) Able to grow a large nut in our cool season.
4) Able to grow on cool, more moist, neutral
(pH 7) soil.
5) Tiny buds which discourage bud gall insects.
6) Conservative bearing with few and small nuts
until Japanese trees are large, and their root
systems are extensive.
7) Thin, non hardy bark where young trees
typically decline to multi stems due to
Southwest injury, and -29 C (-20 F)
temperatures.
Traits we see in Chinese:
1) Blight resistance which is equal, but different
from Japanese.
2) Thin pellicle which easily skins off the
smooth, medium size nut kernel.
3) Hardiness between Japanese and American if
the growing season is hot enough and long enough.
4) Excellent flavor, medium size, northern nuts
which are larger and more solid than American.
5) Twig blight susceptibility which can be as
bad as the bark blight.
Traits we see in American
.2) Two strains, one for acid droughty soil and
timber, another for pH 6.x calcium-magnesium,
moderate-water-table soil for up to 1" nuts.
3) Nuts with more glycerides which enhance
sweetness. and frost protection in uncured nuts.
4) Some blight resistance in some remaining trees.
We have gone generations into hybridizing
chestnuts, enough to see what is working and
what is so frustrating it only gives a glimmer of
hope. By far the most successful hybrid in the
Great Lakes region is the Japanese hybrid.
These are not first generation hybrids due to
their tender bark, but are crosses with three part
hybrids, many from Jack U. Gellatly's former
planting in British Columbia, CAN. The
'Colossal', a Japanese x Marrone hybrid, is
almost too tender to grow, and cross, though it
has met with some success in Michigan. It is
unlikly cleaver growing will get around the bark
injury and sloughing due to Southwest injury
seen in our recent mild winters. Clever breeding
and stressing is needed to ferret out hybrids that
retain tips after -31 C (-25 F) winters.
Why do American people think a hybrid
chestnut is automatically a Chinese x American?
Because most crossing was done near
Washington, DC where large Chinese chestnuts
are plentiful, and their first generation hybrids
are hardy. Later hybridizing moved to
Connecticut where Japanese and Japanese
hybrids are hardy even in their first generation.
Chinese chestnut is much better tasting than
Japanese. Chinese adds bark blight resistance
even in the first generation. However, the
farther north Chinese is grows, the more
succeptible susceptible it is to twig blight. Twig
blight can descend down the twig into the bole
of the tree, and make it look like it is
housekeeping for a flock of woodpeckers. This
same infested Chinese could be a prize selection
in the South, but worthless in the North because
temperatures below --18 C ( 0 F) is what kills
the infected bark. Japanese adds blight
resistance, early ripening nuts, and cool season
hardening trees much better adapted to Ontario
or New York though imperfectly in the first
generations of their hybrids. People do not like
the habit of Japanese type trees girdling down,
then sizing several leaders larger than pole size
trees before large nuts and bumper crops are
produced. Marrone hybrids need a very warm
and late fall to complete their season
re-energizing their tree for the coming season.
Without a “Maryland fall” the Marrone hybrids
usually give a few good crops of large nuts
before their energy and fluids-circulation drops,
and they decline into large crops of small nuts,
then expend all their energy in bearing in too
cool and too short a growing climate. Bark
injury is inevitable which leads to resprouting up
from the ground to do this cycle again. Now,
however, we are looking through the seedlings
from Marrone hybrids, and we find
improvement.
One has to grow many chestnut hybrids to perceive that the surviving population is slowly moving to more and more Japanese characteristics. A grower with a few trees who is growing out his selections needs more than a lot of luck because magic bullet breeding is not chestnut breeding. We find a good tree among many failures. Moving to the next generation of better trees is usually lost due to lack of tree numbers and harsh, challenging conditions which push the next generation to a remnant of good hybrid seedlings.
Once we see which way successful breeding is going, the process is simplified. Some sources of Japanese used today are from Connecticut, Etter, various parks, and plantings. However, most of us in the Society of Ontario Nut Growers were led to Japanese through Gellatly hybrids. Japanese have the skinnyest leaves. Shiny leaves is maximized in the 'Skookum' (Gellatly's 'Skyoka' derivative) which is like looking at a holly. Original Gellatly hybrids often look like Chinese x Marrone. Later generations of Gellatly hybrids have given good hybrids, very few, due to containing the too late ripening and too late re-energizing Marrone European. Gellatly hybrids which made hardy trees were early ripe, and close examination showed the purple tinge of Japanese bark. Then we see more Japanese characteristics in buds, leaves, twigs, stems, nuts and burs. Keying in on second year seedlings which retain shiny leaves keeps us going in the right direction by staying with Japanese endowed hybrids. The perception grows that eventually most of our chestnuts orchard trees will be Japanese x Chinese x American hybrids. Sorting generations, these nuts will yield top quality hybrids called,,, 'I don't know'... it was suggested "Multys".