JANUARY 1973
PURPLE-
two disease resistant plums
for the commercial market
AGRICULTURAL EXPERIMENT STATION/AUBURN UNIVERSITY
R. Dennis Rouse, Director Auburn, Alabama
LEAFLET 85
CRIMSON and PURPLE'
Two Disease Resistant Plums
For The Commercial Market
JOSEPH D. NORTON'
CRIMSON AND PURPLE are new plum
varieties developed by the Auburn Uni-
versity Agricultural Experiment Station
for production in central and northern
Alabama. The new varieties have proved
their ability to make good yields of high
quality fruit where bacterial spot, bac-
terial canker, black knot, ring spot, and
green mottle are problems.
The new varieties have high resistance
to the above diseases. In addition, Crim-
son has moderate resistance to brown rot.
Such resistance is particularly important
in the Southeast where prevalence of
these diseases and susceptibility of com-
mercial varieties has discouraged plum
production.
Resistance to one or more of the com-
mon fungal, bacterial, and virus diseases
was present in the parents of the varie-
ties; however, neither parent possessed
resistance to all of them.
ORIGIN
Crimson was selected from a cross of
Bruce X Methley. It combines the re-
sistance to bacterial and fungal diseases
from Bruce with the resistance to virus
diseases and high quality fruit of Meth-
ley, Tables 1 and 2.
Purple was developed from a cross of
Methley X Ozark Premier. It received
resistance to bacterial and fungal diseases
from Ozark Premier and additional re-
sistance from a combination of genes
from both parents, Table 1. Resistance to
1 On cover: Parent varieties, Bruce, left,
and Methley, right.
2 Associate Professor, Department of Horti-
culture.
virus diseases was secured from Methley
and good fruit quality was inherited
from Methley and Ozark Premier, Ta-
ble 2.
Trees of Crimson and Purple are vig-
orous and disease-free. Growth habit of
Crimson is spreading with medium green
foliage and trees of Purple are erect
with dark green leaves.
FRUIT QUALITY
Fruit of Crimson are crimson red ex-
ternally and internally. Color develops
about 3 weeks before fruit are mature.
The fruit are very firm at maturity and
of excellent quality at maturity, Table
2. Fruit size is 1'/2 to 13 inches in
diameter. The flesh clings to the pit.
Purple fruit are dark red externally and
cream colored internally at maturity.
Color develops about 3 weeks before
maturity. Fruit are firm and of good
quality when mature. Fruit size is 13 -2
inches in diameter. The fruit are semi-
cling.
Both Crimson and Purple may be
stored for 3 weeks or more to extend the
marketing period, Table 3. The firmness
of the fruit makes them suitable for han-
dling, storage, packing, and shipping
to local and distant markets.
Grown under the numbers Bruce 12-14
(Crimson) and Methley 11-63 (Pur-
ple), the two varieties have been in
trials at several locations of the Auburn
University Agricultural Experiment Sta-
tion System and in other Southern States.
They compare favorably with other varie-
ties in yield and quality. Since they ma-
ture later than other varieties the market-
TABLE 1. DISEASE RESISTANCE OF PLUM VARIETIES
Disease index'
Variety Bacterial Bacterial 
Black Ring Green 
Brown Av.
spot canker knot spot mottle rot
Bruce 0 0 0 5 5 4 2.8
Crimson- -- - 0 0 0 0 0 1 0.2
Methley - 3 5 5 0 0 3 
2.7
Ozark Premier ----------------- 0 1 1 3 3 3 1.6
Purple 0 0 0 0 0 
3 0.5
'Disease Index: 0 - No injury, 5-- Severe injury.
TABLE 2. CHARACTERISTICS OF PLUM VARIETIES
Bloom Har- Fruit Flesh Skin Fla- Fir- Stone Tex Solu-
Variety date vest Size Shape a- free- 
ble
Variety date set 
color color Size 
vor ness ness 
ture solids
Bruce 3/20 6/29 5 orange orange 13/4-2 5 3 
3 cling 3 9.4
to red to red
Crimson 3/22 7/15 5 crimson crimson 1/- 5 
5 5 cling 5 16.3
red red 14
Methley 3/22 6/10 5 dark dark red 1-114 
5 5 3 cling 5 18.5
red to purple
Ozark 3/20 7/10 5 cream red to 2-214 5 
5 4 free 5 15.7
Premier purple
Purple 3/24 7/20 5 cream dark red 134-2 
5 5 5 semi 4 14.8
to purple cling
Santa 3/24 7/5 4 red darkred 
1/4-11/2 5 5 5 cling 5 16.7
Rosa to purple
Rating Index: 5 = Excellent, 4 = Good, 3 = Fair, 
2 - Poor, and 1 = Very Poor.
ing period may be extended, Table 2.
Thus, they should help fill the need for
commercially acceptable varieties of
good quality for production in the South.
Trees of Crimson and Purple should
be available for planting in the winter
of 1973-1974.
ACKNOWLEDGMENTS
The author gratefully acknowledges
the essential assistance of C. C. Carlton
and K. C. Short, Chilton Area Horticul-
ture Substation, Clanton, Alabama and
H. M. Bryce, Main Station, Auburn, Ala-
bama in evaluation and propagation of
the varieties.
Valuable assistance was rendered by
J. E. Barrett and H. F. Yates, Gulf Coast
Substation, Fairhope, Alabama; M. H.
Hollingsworth, North Alabama Horticul-
TABLE 3. MARKETABLE PLUM FRUIT
AT 350 F STORAGE
Variety Weeks of storage
3 6 9 12 14
Pet. Pet. Pct. Pet. Pct.
Bruce ---- 20 5 0 0 0
Crimson---- 100 90 65 30 15
Methley . 95 70 20 0 0
Ozark
Premier . 90 65 15 0 0
Purple .100 85 55 25 8
Santa Rosa. 100 80 45 20 5
ture Substation, Cullman, Alabama; and
C. A. Brogden, (retired) Wiregrass Sub"
station, Headland, Alabama, in conduct-
ing variety trials.
The assistance of growers in conduct-
ing commercial grower trials of the ma-
terial is deeply appreciated.