'Charleston Gray', and some other
varieties was also started in 1972.
This was a comprehensive program
that required continued selling,
backcrossing, and greenhouse test-
ing in a specific sequence, but it
seemed to be the most promising
method for getting improved wilt
resistance in 'Jubilee' and other
commercial cultivars. Test results
with backcross lines of 'Jubilee' and
'Charleston Gray' in 1978 were en-
couraging enough to warrant in-
creasing seed for replicated and
grower testing. Tests since 1978 have
shown that backcross lines are su-
 ME= IN 11 NF1W


perior to the recurrent parent lines
not only in resistance to Fusarium
wilt but in many other characteris-
tics.
 1973. Crosses were made begin-
ning in 1973 between some of our
more promising selections and sev-
eral Kentucky short internode
(dwarf) lines. This exchange of
breeding materials was facilitated on
a sabbatical visit here by H.C. Mohr.
Two dwarf mutants in watermelon
are governed by single, nonallelic,
recessive genes, and the F2 from the
cross between them segregates in a
9:3:3:1 ratio, with the double reces-


sive being expressed in a pro-
nounced bush-like plant.
 Work on dwarf lines has been
somewhat limited, but recurrent
backcrosses with our better lines have
been made to both of the single
dwarf types and to the double dwarf.
 1981. In addition to the re-
initiation of work on mosaic resist-
ance this year, we also initiated work
on gummy stem blight resistance.
An earlier attempt to utilize resist-
ance found in wild Citrullus acces-
sions was abandoned because of lack
of facilities and personnel to carry
out the procedures necessary for


imokylee ( 1911)