The Harrison times. (Harrison, Boone Co., Ark) 1876-1938, 1908-12-05

sells of freshly wilcd stem; Q, ehlamydospures
from bark Of root; d, bright red perithecla
from root Of dead plant; e, asei and aseos'
3ores borne in the perltneeia.
that as a general rule the large-bol
sorts. Russell, Truitt etc. are more
subject to wilt than other groups OF
varieties. The most resistant of the
American Upland varieties tested was
the Jaskson Limbless, which produced
about 40 per cent of crop where
other kinds failed The original Jack
son was not sufficiently resistant to
justify its general cultivation, but it
has been of value as a basis for breed
ing better races,
Egyptian cotton is more resistant TO
wilt than Upland cotton, but it has
not as yet been found practicable to
III lize this quality, as the Egyptian
varieties do not succeed in our South
eastern States and it is easier to breed
resistance direct from Upland yarie-
ties than from crosses with Egyptian
cotton.
The individual differences in cotton
plants have been utilized as a basis
for breeding new resistant strains.
The work of the Bureau of Plant In
dustry has now been continued along
this line for eight years, and has re-
suited in the successful development
of two new varieties that cairN be
grown on the worst infected land, pSo-
yided rotation of crops for the COM
troll of root-knot is practical.
The development of such varieties
however, is neither quickly nor easily
accomplished but requires breeding
by exact methods for several years.
1t will not suffice to send pickers
through the fields to gather seed cot
ton from apparently resistant plants,
as some have recommended. Our eX-
perience has been that such mass Sc
lection is expensive and ineffective.
Much of the seed obtained Is taken
from plants not truly resistant, ana
the succeeding crop is nearly as much
diseased as the first While such
method should result in increasing
the resistance of the crop in the long
run, the cross-pollination between re-
sistant and nonresistant plants greatly
delays the results. The correct
method is to select with great care
a small number of plants that appear
to be healthy, though growing in the
worst infected areas. The seed from
each of these plants must be kept
separate and planted in parallel rows
frba
resulting progeny will show which OF
the plants selected transmits the re-
sistant quality in the most effective
manner The rows will also vary
much in productiveness and other
qualities. The best one should be Sc
lected and the other discarded, In
some cases a resistant row of salts
factory quality has been found the
first year, and only two more sea
sons were required to multiply the
seed, but more often complete success
has not been had at once and the
work had to be repeated
The origination of new wilt.resistant
varieties is work for the plant breeder
rather than the general farmer, and
there is need for men in every county
TO take up the business of breeding
to supply this demand. The farmer,
however, should practice selection to
further improve the strain purchased
from breeders, or at least to preserve
Ii from deterioration. The Bureau OF
Plant Industry desires to stimulate
the breeding and sale of improved
varieties of cotton. To this end it will
place the varieties already developed
in the hands Of men who will improve
them and offer them for sale.