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Uz => DEPARTMENT OF AGRICULTURE,

BUREAU OF PLANT INDUSTRY—-BULLETIN NO. 90, PART I.
SB 201 B. T. GALLOWAY, Chief of Bureau.

THE STORAGE AND GERMINATION OF
WILD RICE SEED.

BY

IW. T. DUVEL,

ASSISTANT IN THE SEED LABORATORY.

IssuED SEPTEMBER 7, 1905.

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Fall seeding versus spring seeding - - -
Directions for storing the seed......-

Detailed conditions and results of storage experiments --....---.------------

Packing for transportation ......-..--
Methods of making germination tests
Effect of temperature on germination
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Meseription of plates._......-.-.-.--

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THE STORAGE AND GERMINATION OF WILD
RC SEE).

INTRODUCTION.

The seed of wild rice, sometimes called Indian rice or water oats
(Zizania aquatica L.), has always been a very valuable food among
the Indians, especially those of the upper Mississippi Valley. Of
recent years wild rice has found a place on the menu cards of some
of our best American hotels. The rich and highly nutritious grains,
together with the slightly smoky flavor it has when properly pre-
pared, make it an extremely palatable article of diet. If it were not
for the difficulties of harvesting the seed and preparing the finished
product for market it is probable that wild rice would find a place in
many American homes.

At present, however, the greatest interest in wild rice is created by
the value of the seed as a food for wild waterfowl, particularly wild
ducks. Asa result of this interest the propagation of wild rice from
seed has become a question of considerable importance, especially to
the members of the gunning clubs throughout the United States and
Canada.

DISTRIBUTION.

The distribution of wild rice is now reported from New Brunswick
and Assiniboia south to Florida, Louisiana, and Texas. There are,
however, comparatively few localities in which it grows abundantly.

a Wild rice is considered one of the most important foods for wild ducks and other
waterfowl, and a large number of inquiries have been received from members of
gunning clubs throughout the United States asking where good, germinable seed can
be secured. Itis quite generally recognized that wild rice seed loses its vitality if
allowed to become dry, and better methods of storing the seed during the winter
have long since been demanded.

The results of investigations begun two years ago show that wild rice seed can be
handled without any deterioration in vitality if it is harvested and stored according
to methods outlined in the present paper.

J. W. T. Duvet, Acting Botanist in Charge of Seed Laboratory.

Seep LABORATORY,
Washington, D. C., July 20, 1905.

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6 STORAGE AND GERMINATION OF WILD RICE SEED.

Good reasons exist for assuming that this area can be extended to —
include all fresh-water lakes, as well as swamps and river bogs, where |
the water does not become stagnant, throughout the whole of North
America south of latitude 55° north. Wild rice also grows luxuri-
antly along the lower parts of many of the rivers of the Atlantic Coast —
States, the waters of which are affected by the action of the tide to a
considerable degree, and consequently contain an appreciable quantity
of salt. It has been shown” that the maximum degree of concentra-
tion of salt water in which wild rice plants can grow successfully is
equivalent to a 0.03 normal solution of sodium chlorid. This concen-
tration corresponds to 0.1755 per cent by. weight of sodium chlorid,
which is sufficient to give a slight salty taste to the water.

HABITAT.

While it is well recognized that the habitat of the wild rice plant is
in shallow fresh water, it is now known that it will grow luxuriantly
in water containing little less than two-tenths of 1 per cent of sodium
chlorid. Occasional plants have been found growing in water which
contained, for short periods at least, nearly double that amount of
salt. These facts indicate the possibility of a much wider range of
conditions to which this plant may be subjected without hindering its
development. It is not beyond the range of possibility—indeed, it is
quite probable—that by careful selection plants may be obtained which
will thrive on soil that is comparatively dry, at least in places in which
the water can be drawn off gradually during the latter part of the
growing season.

In September, 1904, Mr. G. C. Worthen, of the Bureau of Plant
Industry, collected a cluster of wild rice plants which were growing
on the Potomac Flats, near Washington, D. C., in soil which was suf-
ficiently dry to permit the use of a 2-horse mowing machine for cutting
down the rank growth of vegetation. This was newly made land, and
in all probability the seed giving rise to this cluster of plants was
pumped in with the dirt from the Potomac River the year previous.

This amphibious type once established, it will undoubtedly carry
with it a strain of seed which can withstand considerable drying with-
out any marked injury to its vitality. Such being true, the methods
and difficulties of propagation from seed would be greatly simplified.

Simultaneous with establishing an amphibious type should come the
selection of seed plants which are capable of retaining their seed until
the larger part of it has reached maturity. These two steps once
made, the future of wild rice as a cereal will be assured.

«The Salt Water Limits of Wild Rice. Bulletin No. 72, Part II, Bureau of Plant
Industry, United States Department of Agriculture, 1905.

\ FALL SEEDING VERSUS SPRING SEEDING. 7
GERMINATION OF THE SEED.

The greatest difficulty to be overcome in extending the area for
growing wild rice is the poor germination of the commercial seed.
Inasmuch as wild rice constitutes one of the most important foods of
wild ducks and other wild waterfowl, many individuals and most of
the gunning clubs east of the Rocky Mountains have been asking the
question, How can we propagate wild rice from seed in order to estab-
lish better feeding and fattening grounds for our game birds?

The many failures in the propagation of wild rice from seed have
been due to the use of seed that had become dry before sowing, or to
the fact that the seed when sown fresh in the autumn had been eaten
by ducks or other animals or was carried away by heavy floods before
germination took place.

It is now very generally known that the seed of wild rice, if once
allowed to become dry, will not germinate, save possibly an occasional
grain. In its natural habitat the seed, as soon as mature, falls into the
water and sinks into the mud beneath, where it remains during the
winter months, germinating the following spring if conditions are
favorable.

Heretofore the plan generally followed, and the one usually recom-
mended by those who have given some attention to the propagation of
wild rice, was practically that of natural seeding; that is, to gather the
seed in the autumn, as soon as thoroughly mature, and, while still fresh,
to sow it in 1 to 3 feet of water.

FALL SEEDING VERSUS SPRING SEEDING.

It must be remembered that the bulk of the seed remains dormant
during the winter, germinating first the spring after maturing; con-
sequently, with but few exceptions, fall seeding is unsatisfactory and
unreliable. Fall seeding is likely to prove a failure for three reasons:
(1) Wild ducks and other animals of various kinds eat or destroy the
seed in considerable quantity before it has had time to germinate the
following spring; (2) much of the seed is frequently covered so deeply
with mud that washes in from the shore during the winter that the
young plants die of suffocation and starvation before they reach the
surface; (3) in some cases a large quantity of the seed is carried away
from the place where sown by the high waters and floating ice prey-
alent during the latter part of the winter and early spring.

In exceptional cases these difficulties can be overcome; under which
circumstances autumn sowing may be preferable to spring sowing.
In the majority of cases, however, much better results will be
obtained if the seed is properly stored and sown in the early spring,
as soon as the danger of heavy floods is passed and the water level
approaches normal.

8 STORAGE AND GERMINATION OF WILD RICE SEED.

In sowing the seed considerable care must be exercised in selecting —
a suitable place, securing the proper depth of water, ete. Good
results can be expected if the seed is sown in from 1 to 3 feet of water
which is not too stagnant or too swiftly moving, with a thick layer of
soft mud underneath.” It is useless to sow wild rice seed on a gravelly
bottom or in water where the seed will be constantly disturbed by
strong currents.

Previous to this time, save in a few reported cases, the seed which
was allowed to dry during the winter and was sown the following
spring gave only negative results. It is now definitely known that
wild rice, if properly handled, can be stored during the winter without
impairing the quality of germination to any appreciable degree, and
that it can be sown the following spring or summer with good success.

DIRECTIONS FOR STORING THE SEED.

The vitality of wild rice seed is preserved almost perfectly if kept
wet in cold storage—Nature’s method of preservation. This method
of storage implies that the seed has been properly harvested and cared
for up to the time of storage. The seed should be gathered as soon
as mature, put loosely into sacks (preferably burlap), and sent at once
to the cold-storage rooms. If the wild rice fields are some distance
from the cold-storage plant the sacks of seed should be sent by express,
and unless prompt delivery can be guaranteed it is not advisable to
send by freight even for comparatively short distances. It is very
important that the period between the time of harvesting and the
time when the seed is put into cold storage be as short as possible.
If this time is prolonged to such an extent as to admit of much fer-
mentation or to allow the seed near the outside of the bags to become
dry during transit, its vitality will be greatly lowered.

It is not practicable to give any definite length of time which may
elapse between harvesting and storing, inasmuch as the temperature,
humidity, and general weather conditions, as well as the methods of
handling the seed, must be taken into consideration. Let it suffice to
say, however, that the vitality of the seed will be the ec the
sooner it is put into cold storage after harvesting.

As soon as the seed is received at the cold-storage plant, while it is
still fresh and before fermentation has taken place, it should be put
into buckets, open barrels, or vats, covered with fresh water, and
placed at once in cold storage. If there is present a considerable
quantity of light immature seed or straw, broken sticks, ete., it will
be profitable to separate this from the good seed by floating in water

«Wild Rice: Its Uses and Propagation. Bulletin No. 50, Bureau of Plant Industry,
United States Department of Agriculture, 1903.

‘ STORAGE EXPERIMENTS. 9

preparatory to storing. The storage room should be maintained at
a temperature just above freezing—what the storage men usually
designate as the ‘‘ chill room.”

When taken from cold storage in the spring the seed must not be
allowed to dry out before planting as a few days’ drying will destroy
every embryo.

Seed which was stored under the foregoing conditions from October
19, 1903, to November 15, 1904, 393 days, germinated from 80 to 88
percent. Another lot of seed, which was stored on October 6, 1904,
- and tested for vitality on April 17, 1905, germinated 79.8 per cent.
Plate I shows the luxuriant Swill made by the seed which was kept
wet and stored at a temperature of 32° to 34° F. for 393 days.

DETAILED CONDITIONS AND RESULTS OF STORAGE EXPERI-
MENTS.

The foregoing conclusions are based on the results obtained from
two series of experiments, as follows:

In October, 1903, a box of wild rice seed was received from Ontario,
Canada. This seed, as soon as gathered, was loosely packed in moist
sphagnum and sent by express to the Seed Laboratory of the United
States Department of Agriculture. After a few days, while it was
yet moist and before any fermentation had taken place, the seed was
divided into four lots for special treatment, as follows:

(1) Seed submerged in water and placed in cold storage at a temper-
ature of 32° to 34° F.

(2) Seed submerged in water and placed in cold storage at a temper-
ature of 12° F. The seed was soon embedded in a solid mass of ice
and remained so until samples were taken for test. —

(3) Seed, without the addition of water, put into cloth bags and kept
in cold storage at a temperature of 32° to 34° F.

(4) Seed, without the addition of water, put into cloth bags and kept
in cold storage at a temperature of 12° F.

In October, 1904, a second consignment of seed was received from
Minnesota, and the following additional storage experiments were
made by Mr. C. S. Scofield, of the Bureau of Plant Industry.
(5) Seed submerged in water and placed in cold storage at a temper-
ature of 32° to 34° F., as in No. 1.
(6) Seed submerged in water and placed in cold storage at a temper-
ature of 12° F., as in No. 2.
(7) Seed submerged in water in a galvanized-iron bucket and stored
on the roof of the laborator y building. The water was changed daily
when not frozen.

10 STORAGE AND GERMINATION OF WILD RICE SEED.

(8) Seed submerged in water in a galvanized-iron bucket and stored
on the roof of the laboratory building, as in No. 7. In this case the

water was not changed save to replace the loss due to evaporation. ~

(9) The conditions for No. 9 were the same as those for No. 8,
except that air was forced into the water daily when not frozen solid.

Samples of seed were taken from the different lots and tested for
vitality at irregular intervals throughout the time of storage, which,
in the former series, extended over a period approximately thirteen
months and in the latter series over a period of little more than six
months.

Experiments Nos. 1 and 5.—The seed which was submerged in water
and stored in the ‘‘chill room” showed no deterioration in vitality.
The results of the finai tests gave a germination varying from 79.8 to
88 percent. This is practically Nature’s method of preserving the
vitality of the seed during the winter.

Experiments Nos. 2 and 6.—The seed which was submerged in
water and stored at a temperature of 12° F. was all killed before the
spring following the date of storage. Soon after being placed in stor-
age the water was frozen solid and the seeds were embedded in a mass
of ice, in which condition they remained throughout the experiment,
a portion being cut out from time to time for germination tests. The
complete loss of vitality in these two lots of seed:is attributed not to
the freezing directly, but to the thorough desiccation as a result of
the continuous low temperature.

Experiments Nos. 3 and 4.—The samples of seed which were stored
in cloth bags at the temperatures of 32° to 34° F. and of 12° F. had,
for all economic purposes, entirely lost their vitality. The average
percentage of germination, as shown by the 37 tests made from each
of the two lots, was less than five-tenths of 1 per cent.

Experiment No. 7.—The seed which was submerged in water and
stored on the roof of the laboratory building, the water being changed
daily, showed a good percentage of germination when the last vitality
tests were made. If only a small quantity of seed is desired for the
spring planting and cold storage can not be readily secured, good
results may be obtained by this treatment; but it is much less certain
and probably more expensive than keeping the seed in cold storage,
and for this reason is not recommended. The success of this method
will likewise depend largely on the temperature of the water.

Experiments Nos. 8 and 9.—On April 22, 1905, samples taken from
each of these two lots of seed showed a marked deterioration in vitality.
Thoroughly mixed samples from No. 8 showed a vitality of only 58
per cent, while No. 9 had deteriorated to 14.3 per cent.

METHODS OF MAKING GERMINATION TESTS. rE
PACKING FOR TRANSPORTATION.

Too much care can not be given to the matter of packing the seed
for transportation, for unless the packing is properly done the vitality
of the seed will be destroyed during transit. What is here said applies
to fresh seed which is to be sown in the autumn, as well as to seed
which has been kept in cold storage during the winter. It must not
be forgotten, however, that the vitality of cold-storage seed is more
quickly destroyed on drying than that of fresh seed.

For transportation the seed should be carefully packed, with moist
sphagnum, cocoanut fiber, or fine excelsior, in a loosely slatted box.
If the time of transportation does not exceed five or six days no spe-
cial precautions need be taken as to the temperature. During the
period of transportation it is quite probable that some of the seed will
germinate, but if sown at once growth will not be retarded and the
roots will soon penetrate the soil and anchor the young plants.

If the time of transportation is necessarily long, it is recommended,
if the best results are desired, that some provision be made for a
reduced temperature. The nearer the temperature approaches that of
freezing the better. It has been demonstrated, however, that a fair
percentage of seed will remain germinable for a considerable time if
packed as above described.

On October 10, 1904, Mr. C. 8S. Scofield sent a small quantity of
wild rice, packed in moist sphagnum moss in a well-ventilated box, to
Doctor De Vries, of Amsterdam, Holland. On October 14 or 15 this
box was placed in cold storage on the steamer in New York Harbor.
The box of seed was received by Doctor De Vries in good condition on
November 2, twenty-one days after the seed was packed for shipment.

METHODS OF MAKING GERMINATION TESTS.

The samples were tested (1) between folds of blotting paper—our
regular method for testing the germination of most seeds—and (2) in
water, Nature’s method of sowing wild rice seed. The latter method
gave much better results and was the one finally adopted for the
laboratory tests. The seed should be covered with water, the water
in the dishes to be changed daily.

Plate I shows the importance of making the germination tests in
water, as described in the foregoing paragraph. The seed was covered
with water and placed in a germinating chamber maintained at an
alternating temperature of 20° C. (68° F.) for eighteen hours, and
30° C. (84° F.) for six hours, until the majority of the seeds had
germinated. At this stage the dish containing the seeds was trans-
ferred to the worktable, which was exposed to the temperature of the
laboratory—approximately that of a living-room. The water in the

12 STORAGE AND GERMINATION OF WILD RICE SEED.

dish was changed daily during the period of germination, and water
was afterwards added at irregular intervals to replace the loss by —
evaporation. i

Plate IJ shows somewhat in detail the different stages in the germina-
tion of wild rice seeds. The seeds and seedlings are shown in natural —
size. In bande the first sheath has just burst through the seed coats, —
taking a position at right angles to the seed proper. The lateral roots
begin to emerge when the first sheath leaf has attained a length of 4 to
1 inches. From this time growth continues rapidly, and by the time ~
the seedlings are 2 or 3 inches long the root system is very well
developed (f and g). At this stage under favorable conditions the
plants have a good hold in the soil and will not be washed away by an —
ordinary freshet. The relative position of the actively growing —
seedling is always at right angles to that of the old seed, as shown in ~
f and ¢.

EFFECT OF TEMPERATURE ON GERMINATION.

Germination tests were made at constant and alternating tempera- —
tures, ranging from 15° to 35° C. (59° to 95° F.). While no effort 3
was made to show the minimum and maximum temperatures of ger-
mination, the percentage was somewhat reduced ata constant tempera-
ture of 35° C., and the maximum is not much above that. All of the
other temperatures gave good results. The lower temperatures, how- —
ever, were slightly more favorable than the higher. These facts are —
valuable to show that the wild rice plant can thrive in either warm or —
cold water, but better, perhaps, in northern than in southern latitudes.

SUMMARY.

(1) Under no circumstances should wild rice seed which is intended
for planting be allowed to dry. Dried seed will germinate but rarely
and should never be sown. : : 7

(2) Wild rice seed can be stored without deterioration if it is gath-
ered as soon as matured, put into barrels or tanks, covered with fresh ~
water, and, before fermentation has set in, stored at a temperature of
32-34° F, Seed treated in this way germinated as high as 88 per cent
after being in storage 393 days. Fresh seed seldom germinates better,
and usually not so well. |

(3) After the seed is taken from cold storage it should not be J
allowed to dry. The vitality of cold-storage seed is destroyed on
drying even more quickly than that of fresh seed.

(4) For transportation the seed should be packed in moist sphagnum,
cocoanut fiber, or fine excelsior. If not more than five or six days
are required for transit, no special precautions need be taken for con-—
trolling the temperature; but if the time for transportation exceeds

i SUMMARY, 13

_ six days, provision should be made for a temperature sufticiently low

to prevent marked fermentation. A temperature approximately
freezing will give the most satisfactory results.

(5) Wild rice can be sown either in the autumn or in the spring.
Spring sowing is preferable, thus avoiding the danger of having the
seed eaten or destroyed by wild ducks or other animals during the fall
or winter, or of its being buried or washed away by the heavy floods
of late winter or early spring.

(6) Wild rice should be sown in the spring in from 1 to 3 feet of
water which is neither too stagnant nor too swiftly moving, as soon as
the danger of heavy floods is passed.

(7) Wild rice is of the greatest importance as a food for wild water-
fowl, likewise a delicious breakfast food for man, and the area in which
it is extensively grown should be extended. It will grow luxuriantly
in either warm or cold water; furthermore, it can be grown success-
fully in water which is slightly salty to the taste.

(8) In determining the vitality of any sample of wild rice seed the
germination tests should be made in water—the condition under which

the self-sown seed germinates.

wes ee

(9) The seed will germinate well at temperatures ranging from
15° to 30° C. The maximum temperature of germination is above
35° C. (95° F.), but better results are obtained at lower temperatures.

et"

15

DESCRIPTION OF PLATES.

Piate I. Wild rice growingin water. This seed was submerged at a temperatu
32-34° F. for approximately thirteen months. In making the germination test
the seed was covered with water and placed in a germinating chamber ;
tained at a temperature of 20° C. (68° F.) for eighteen hours, and at 30°
(86° F.) for six hours. After the majority of the seeds had germinated the c
was transferred to the worktable of the Seed Laboratory. 3

Puate II. Progressive stages in the development of wild rice seedlings; f and g, see
lings showing the relative position of the growing seedlings and the parent seed
which take a position at right angles to each other when grown normally i in
water. (Natural size. ) “i

16

Bul 90, Pt. |, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE |.

WILD RICE GROWING IN WATER AFTER BEING KEPT WET IN COLD STORAGE AT A TEM-
PERATURE OF 32-34° F., FROM OCTOBER 19, 1903, TO NOVEMBER 15, 1904.

Bul. 90, Pt. |, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE II

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Vi

STAGES OF GERMINATION OF WILD RICE, SHOWING THE DEVELOPMENT OF THE
Root SYSTEM AND THE RELATIVE POSITION OF THE SEEDLING AND THE
PARENT SEED. NATURAL SIZE.

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