liq

ii

in

First Printing 3M, April 1996

Information contained herein is available to all persons without regardto race, color, sex, or national origin.

PLUM VARIETY AI ALABAMA 1 6-f
G.E. BOYHAN, J.D. NORTON, M.H. HOLLIN J.A. PITTS, J.B. WITT, H.W. IVEY, AND J.T. OWEN

9

INTRODUCTION
Plums are an important horticultural crop in many parts of the world including Europe, Asia, and North America. There are some 18 species of plums that have contributed germplasm to commercial plum production (11). Of these, only a few are of primary economic importance. Perhaps the most important plum in the United States is Prunus Domestica L., which is the primary germplasm source for fresh market and prune-type plums. The second most important germplasm source is P. salicina Lindl., the primary genetic source of fresh market Japanese plums. Plums grown in the Southeast are primarily fresh market Japanese plums. Plum production in Alabama has traditionally been associated with peach production centered in the Chilton County area. Culturally, plums require similar or identical rootstocks, nutrient and water requirements, pest control, pruning, and harvesting as those used for peaches. This study was undertaken to evaluate commercially available plum cultivars and advanced breeding lines for performance throughout Alabama.

MATERIALS AND METHODS
Plantings were established in 1986 and 1987 at five research stations in Alabama. An additional planting was established in 1990. Plantings were established in 1986 at the Wiregrass Substation (Headland), the Chilton Area Horticulture Substation (Clanton), and at the Sand Mountain Substation (Crossville). Plantings were established in 1987 at the E.V. Smith Research Center (Shorter) and at the North Alabama Horticulture Substation (Cullman). Additionally, a planting was established at the Piedmont Substation (Camp Hill) in 1990. Prior to planting, land was prepared according to Auburn University soil test recommendations. Trees were planted with a 20-foot between-row spacing and a 20-foot within-row spacing, except at the Wiregrass Substation where in-row spacings were 15 feet. Trees were trained to an opencenter and were pruned in late winter according to standard practices. Each trial consisted of 21-25 cultivars (tables 1-6 and figures 1-3).
Boyhan is a Senior Research Associate and Norton is a Professor Emeritus of Horticulture. Hollingsworth is Retired Superintendent of the North Alabama Horticulture Substation, Eason is Retired Superintendent of the Sand Mountain Substation, Pitts is Superintendent of the Chilton Area Horticulture Substation, Witt is Superintendent of the E.V. Smith Research Center Horticulture Unit, Ivey is Retired Superintendent of the Wiregrass Substation, and Owen is Superintendent of the Piedmont Substation.

2

ALABAMA AGRICULTURAL EXPERIMENT STATION

All plantings were arranged in randomized complete block designs with single-tree replicates. The trials at Wiregrass, Chilton, and Piedmont consisted of six replications while those at E.V. Smith, Sand Mountain, and North Alabama consisted of four replications. Bloom dates and harvest dates were recorded for each tree at each location. Bloom dates reflect trees that had at least 50% of their blooms open. The range of bloom dates reported was calculated by averaging the earliest recorded bloom dates and averaging the latest recorded bloom dates for the years of the study. Harvest dates were calculated in the same fashion (figures 4-6). The bloom and harvest dates were compiled for North, Central, and South Alabama. The North Alabama data are a combination of data collected at the North Alabama and Sand Mountain substations. The Central Alabama bloom and harvest dates consist of data collected at E.V. Smith, Chilton, and Piedmont research units. The South Alabama bloom and harvest dates were collected at the Wiregrass Substation. Yield data were collected annually at each substation; however, not all trials produced fruit each year at all substations. Yield data were expressed as average pounds of fruit per tree for each entry. Ten fruit from each tree were analyzed for skin color, flesh color, fruit length, fruit width, weight, soluble solids, and stone freeness. These data are combined from all locations and all years and are presented in Table 7.

RESULTS AND DISCUSSION
The highest plum yields were observed at the Chilton Area Horticulture Substation (Table 1). The average yield per tree was 55 pounds compared to 26 pounds per tree in a similar trial at Pontotoc, Mississippi (2). Yield consistency from one year to the next was lacking in many varieties with such notable exceptions as AU-Producer (which was among the top five producers four out of the six years of the study) and Byrongold, AU-Cherry, and Methley (which were in the top five three out of six years). The results observed in the trial at the E.V. Smith Research Center are consistent with plum production in Central Alabama (Table 2). The average yield for all cultivars for 1992-1994 was 39 pounds per tree. Several cultivars had yields greater than 50 pounds per tree, particularly in 1993 and 1994, and many had yields of more than 100 pounds per tree. Yield consistency for any particular variety from one year to the next was lacking, however. Extremely high yields one year often were followed by lower yields the next. This may be the result of alternate-year bearing, however, not enough data were available to conclusively draw this inference. Results at the Piedmont Substation were extremely promising. Yields in 1995 were so high that the reported yield results (Table 3) are from only four of the six replications. The overwhelming amount of fruit and a lack of sufficient labor to handle a complete harvest prevented harvest of all replications. Data will continue to be collected from this orchard. Yields at Sand Mountain Substation averaged 24 pounds per tree for the production years of 1991, 1994, and 1995 (Table 4), but in 1992 and 1993 no

PLUM VARIETY TRIALS3

plums were harvested due to late frosts and freezes, a problem that commonly plagues production. Plums typically bloom from the end of February to the middle of March when fluctuating temperatures can damage recently opened flowers. AU-Producer and Methley were among the top five producers in both years that harvests were recorded at Sand Mountain. Yield variability was even more evident at the North Alabama Substation, where data could be recorded for one year only (Table 5). Yields at the Wiregrass Substation also were disappointing. The average yield over the course of the trial was five pounds per tree with a high of 36 pounds per tree for Byrongold in 1992 (Table 6). There were no yields in 1989 and 1990. The trial was terminated early in 1992 because of a dramatic loss of tree vigor and high mortality. More than one-third of the trees had died and another one-third showed dead or dying limbs. This study illustrates that there are some serious unanswered questions concerning commercial production of plums in this area of the state. When bloom dates from North and Central Alabama were compared, an approximate two-week difference in earliest blooms was observed (figures 1-2). The earliest average bloom dates occurred on March 11 in North Alabama and February 23 in Central Alabama. Bloom date comparisons between Central and South Alabama showed that bloom dates for many varieties in South Alabama were later than in Central Alabama. This may be due to inadequate chilling in South Alabama, which results in delayed bloom and lower yields. Of the 24 entries for which bloom dates were recorded in South Alabama, 16 had bloom dates that averaged March 9 or later. Most of the harvest in North Alabama was from June 18 to July 7, but a few varieties ripened earlier or later. In Central Alabama most of the harvest occurred from June 5 to July 4. The range of harvest dates were similar in South Alabama to that in Central Alabama with a few exceptions (CB-28, Homeside, and Mariposa M-1). Fruit quality of plums is often considered to be more important than overall yield (Table 7). Since there are many plum types, it is important to evaluate for fruit quality prior to selection. Some important plum characteristics are fruit size, stone freeness, skin texture, soluble solids, acidity, and firmness. For fresh market production large size is highly desirable. Stone freeness refers to the ability of the flesh to come free from the seed. Plums range from strongly free to fully cling, with free stones considered the more desirable. Skin texture can be smooth or waxy; smooth being more desirable than waxy. Soluble solids refers to the percent of sugar present, which ranges from 10-15%. High sugar content is considered more desirable, but fruit quality also is determined by acid content and other compounds that give the fruit its unique flavor. The skin may be important in this regard because it can impart a bitter aftertaste, which is undesirable. Finally, fruit firmness also is important, particularly after harvest. Some plums soften rapidly after harvest, particularly those with P. angustifolia in their background.

4

ALABAMA AGRICULTURAL EXPERIMENT STATION

OVERVIEW OF VARIETAL CHARACTERISTICS
Many differences exist among the numerous varieties evaluated in this study. The following is an overview of some of the more noteworthy varieties. AU-Amber is a high quality plum developed at Auburn University that has purple skin and yellow flesh (6). It has medium sized fruit with the highest average sugar content of any entry in the trials. One major drawback to this variety is that it blooms early, which often results in reduced or no yields due to late frosts and freezes during the flowering period. AU-Cherry is a high yielding, self-fertile variety (7). It is sweet when fully ripe but has very small fruit and is, therefore, best suited for dooryard and local production. AU-Producer is another high quality Auburn plum with relatively high yields of medium sized, firm fruit. It is somewhat acid until completely ripe. It has an upright growth habit that may require extra care in pruning to prevent weak, narrow crotch angles in scaffold branches. AU-Roadside is a large red plum developed for the local fresh market in Alabama (5). AU-Rosa is a large, firm, high quality plum similar to Santa Rosa with red or yellow skin and yellow flesh (9). The growth habit of this tree is characteristic of Santa Rosa, with an upright vase shape consisting of narrow branch angles. AU-Rubrum is an early-fruiting mutant of Crimson (8). This is a large red plum with good characteristics, is generally stone free, and is early ripening with fair to good yields. Crimson is an Auburn University selection of a cross between Bruce and Methley that produces fruit later than AURubrum and has better disease resistance than Methley (3). Homeside (4) is relatively large in size with good yields of mid- to late-season production. Its skin color is not particularly attractive and the fruit lacks firmness for commercial production; however it possesses good disease resistance. Several advanced breeding lines developed at Auburn University also were evaluated in this study. Auburn #1 is an advanced breeding line that shows promise and may be an Auburn University release in the near future. The CB series cultivars are mid- to late-season plums, mostly red skinned with red flesh. These plums were developed to meet the demand for later season production. CD-90 is a high quality advanced breeding line with yellow flesh and skin. It lacks firmness at maturity and has been eliminated from the breeding program. Frontier M-1 is a dwarf form of Frontier that has been disappointing in production. It may, however, be useful as a rootstock. Methley B-20 is a bright red plum with yellow flesh. This plum tends to be small and the skin has an undesirable waxy texture. Bruce 12-4 (Auburn University germplasm release) produces many fruit on a relatively small tree. The fruit, however, soften quickly making this variety suitable primarily for green plum production. Byrongold, which was released by the U.S. Department of Agriculture at Byron, Georgia, is a large plum, with yellow skin and P. americana in its pedigree (10). This plum produces well and, coupled with its unusual yellow color, should find a following in fresh market production.

PLUM VARIETY TRIALS

5

Methley, which has both P salicinaand P. cerasiferain its background, is probably the most widely grown plum in the Southeast. It is a vigorous tree with small purple fruit but is susceptible to black knot and bacterial canker. The aim of the breeding program at Auburn University has been to improve disease resistance, size, and quality of plums as compared with Methley. Ozark Premier is another popular plum with large yellow-fleshed fruit with red skin and waxy texture. Robusto and Segundo were developed from crosses of P salicinia and P. angustifolia, which results in a somewhat different leaf shape and tree habit (10). They are early, large red-fruited types. This fruit is undesirable, however, because it softens quickly and has only fair flavor. These varieties are more suitable for green plum production. Explorer, another standard variety, is a large, purple, mid-season, poor yielding plum. Frontier is a large red, early- to mid-season plum that produces good yields. Morris is a medium size, red, early- to mid-season plum that also produces good yields. Reports from East Texas trials indicate Morris was the highest yielding variety tested in that trial (1). Santa Rosa, which is particularly susceptible to bacterial diseases, is an early- to mid-season plum with red skin and yellow flesh. It produces large fruit on an upright-growing tree. Upright growth is characteristic of this cultivar and may require extra care in pruning to ensure strong, wide-angle scaffold branches. Shirley is a medium sized plum with red skin and yellow flesh. It is early in production, produces good yields, but has undesirable off-flavors.

CONCLUSION
Based on the results of these trials, plums remain a marginal crop in the Southeast. Market windows exist for green plums and for fresh market, usually in conjunction with other fresh produce, particularly peaches. Inconsistent yields and crop failures, associated with late frosts and freezes during the critical blooming period, plague plums. Additionally, there are several bacterial diseases (plum leaf scald, bacterial canker, and bacterial spot) for which there is only limited tolerance in some varieties, such as AUProducer, Homeside, and AU-Amber. Work continues at Auburn University to develop high quality, disease resistant varieties with an ongoing breeding program. Continued evaluation of the variety trial at the Piedmont Substation and new trials at the E.V. Smith Horticulture Unit and the Chilton Area Horticulture Substation are part of this program. Advanced breeding lines under test include CD-122, which remains free of plum leaf scald (PLS) after several years in evaluation at the PLS evaluation orchard on the main campus of Auburn University. Cooperative work with researchers in Georgia to evaluate new material on a regional basis continues at the Chilton Area Horticulture Substation and the E.V. Smith Horticulture Unit.

TABLE 1. PLUM YIELD RESULTS, CHILTON AREA HORTICULTURAL SUBSTATION, CLANTON

Cultivar AU-Amber AU-Cherry AU-Producer AU-Roadside AU-Rosa AU-Rubrum Auburn #1 Bruce 12-4 Byrongold CB-15 CB-28 CB-68 Crimson Explorer

1989 1990 1991 1992 1993 1994 Average yield ------------------------------------------ (Lb./tree)--------------------------------0 41 1 110 0 71 37 46 60 173 13 34 40 61 46 39 228 13 64 74 77 26 56 72 11 0 5 28 24 39 61 104 0 33 44 7 32 37 1 0 5 14 56 88 115 27 4 6 49 10 121 91 32 1 21 46 25 278 182 95 0 36 103 6 105 63 133 0 9 53 12 125 93 119 0 8 60 28 137 88 95 0 0 58 16 44 54 32 0 3 25 3 9 14 0 0 63 15
rj

PLUM VARIETY TRIALS

7

z 0
F

i i i i

i i i i i i i i i i i i i

z d
OIN

t

U
z OIN

i

i i i i i i

i i

0

i

i

F

i

OIN

i i i i

i i

F 0l
Qi

i i i i

Mk00

ONCN0
' d Od' 0 M -

00

1

i i i i i

i i i i i i i i i i i i i i i i

i i i

00

i i

ONI

O

NO 0

M

C0

i

0c

" 4)

CC3

N

~0 N~
O O p ) N

N0

wwx
i

a) P4 V) V)
O C

8

ALABAMA AGRICULTURAL EXPERIMENT STATION

TABLE 2.

PLUM YIELD RESULTS,

E.V.

SMITH HORTICULTURE UNIT,

SHORTER

1990 1991 1992 1993 1994 Av. yield ----------------------- (Lb./tree)-------------------0 0 17 4 57 16 AU-Amber 58 21 21 AU-Cherry 8 14 4 AU-Producer 2 0 14 18 44 16 AU-Roadside 2 5 0 0 9 3 AU-Rosa 2 3 13 12 22 10 AU-Rubrum 19 8 9 100 4 28 Auburn #1 23 2 28 125 14 38 12 27 32 61 71 41 Bruce 12-4 Byrongold 18 32 70 0 25 29 CB-15 24 1 29 6 23 16 28 23 CB-71 15 17 40 13 36 13 47 23 CD-90 21 0 Explorer 0 0 3 0 10 3 18 0 32 11 Frontier M-1 3 1 Homeside 8 0 19 107 18 30 4 6 22 121 186 68 Methley 22 14 11 43 40 Methley B-20 1 18 25 23 20 17 45 Morris 35 1 34 107 26 Ozark Premier 5 64 22 4 5 15 21 Robusto 48 2 10 90 54 84 Shirley

Cultivar

PLUM VARIETY TRIALS

9

TABLE

3.

PLUM YIELD RESULTS, PIEDMONT SUBSTATION, CAMP HILL

Cultivar Santa Rosa A-li CB-15 Auburn Crimson M-2 Methley F-i-i Ozark Premier AU-Cherry Homeside Robusto AU-Roadside AU-Producer AU-Rosa Methley AU-Rubrum Segundo Methley B-20 Robusto Byrongold CB-122 Bruce 12-4 CB-68 Explorer Shirley CB-28

1993
--

1995
125

Average yield
125

--------(Lb./tree)--- -------

#1

29 12 9 17 5 14 13 17 10 32 18 21 11 8 34 15 18 28 8 2 6 1 23

85 58 104 iii 209 46 26 53 39 120 56 16 85 74 38 67 172 71 143 124 40 114 110

57 35 56 64 107 30 19 35 25 76 37 18 48 41 36 41 95 49 75 63 23 57 66

10

10 ALABAMA AGRICULTURAL EXPERIMENT STATION

TABLE 4. PLUM YIELD RESULTS, SAND MOUNTAIN SUBSTATION, CROSSVILLE

Cultivar

1991

1992 & 1993

1994

1995

Av. yield* 14 44 65 19 8 25 39 10 33 6 16 20 28 7 11 69 11 25 18 22 12

AU-Amber AU-Cherry AU-Producer AU-Roadside AU-Rosa AU-Rubrum Auburn Bruce 12-4 Byrongold CB-15 CB-28 CB-68 Crimson Explorer Homeside Methley Methley B-20 Morris Ozark Premier Robusto Segundo

#1

-----------Lb./tree--------------12 21 14 88 49 75 3 52 NO YIELDS 12 0 24 26 44 27 4 23 0 86 0 14 0 31 31 15 27 31 5 0 0 31 29 41 5 9 14 37 9 24 10 32 4 31

9 29 71 2 11 44 4 13 4 18 13 26 15 2 137 18 22 23 2

*Average yields reflect yields of 1991, 1994, and 1995.

PLUM

VARIETY

TRIALS

11

PLUM VARIETY TRIALS

1

TABLE

5.

PLUM YIELD RESULTS, NORTH ALABAMA HORTICULTURE SUBSTATION, CULLMAN

[Cultivar
AU-Amber AU-Cherry AU-Producer AU-Roadside AU-Rosa AU-Rubrum Auburn Bruce 12-4 Byrongold CA-i CB-15 CB-71 CD-90 Crimson Explorer Frontier M- 1 Homeside Methley Methley B-20 Morris I IOzark 1Premier ~--I

-- -- b./tree - - --L
21 12 29 10 8 15 10 17 29 2 4 52 18 23 18 2 6 35 19 13 71 LC

1991

1992-1994
- -

--- - - - -

- - -

#1

NO YIELDS

12

12 ALABAMA AGRICULTURAL EXPERIMENT STATION

TABLE 6. PLUM YIELD RESULTS, WIREGRASS SUBSTATION, HEADLAND

Cultivar

1988

1989-90

1991

1992

---------------------AU-Amber AU-Cherry AU-Producer AU-Roadside AU-Rosa AU-Rubrum Auburn Bruce 12-4 Byrongold CB-15 CB-28 CB-68 Crimson Frontier M-1 Homeside Mariposa M-1 Methley Methley B-20 Morris Ozark Premier Robusto Segundo 0 6 1 2 2 7 12 1 4 17 10 5 3 1 2 3 1 1 4 7 4 4

Av. yield* 0 3 1 1 1 4 4 0 13 6 3 2 2 0 1 1 5 0 4 3 6 6

Lb./tree-------------------

NOYIELDS

#1

1 1 1 0 0 3 1 0 1 0 0 0 3 0 0 0 2 0 2 1 0 0

0 2 0 0 0 2 0 0 36 1 0 0 0 0 0 0 12 0 7 0 15 14

*Averages reflect yields for 1988, 1991, and 1992 only. Trees were removed at the end of the 1992 season due to high mortality.

Table 7. Fruit Characteristics Entry Skin color Flesh color Soluble solids (Pct.) 16.2 15.4 13.8 12.4 13.5 13.9 14.1 10.5 12.5 15.2 14.6 12.2 14.5 16.4 16.1 Stone freeness* Length (In.) 7.5 3.5
6.1

Width (In.) 1.2 0.9 1.1 1.4 1.5 0.9 1.0 1.1 1.2 1.3 1.4 1.1 0.8 1.6 1.0

Weight (Gins/fruit) 47 22 35 65 72 55 51 45 67 57 55 51 76 41 71

Purple AU-Amber Red/Bronze AU-Cherry Red AU-Producer AU-Roadside Red AU-Rosa Red/Yellow Red AU-Rubrum Red Auburn #1 Red/Orange Bruce 12-4 Yellow Byrongold Red CB-15 Red CB-28 Red CB-68 Red/Purple CB-71 Yellow CD-122 Yellow CD-90
*I cling, 10=free.

Yellow Blood Red Red/Yellow Red Yellow Red Red Yellow/Red Yellow Red Red Red Red Yellow Yellow

5.9 4.6 6.7 6.3 4.1 4.9 5.1 3.9 5.7 8.8 4.2 4.8

1.2 0.8 1.1 1.4 1.4 0.9 1.0 1.1 1.1 1.3 1.4 1.0 0.7 1.5 0.9

TABLE 7, CONTINUED.

FRUIT CHARACTERISTICS

Entry

Skin
color

Flesh
color

Soluble
solids

freeness*
4.1 7.0 3.8 5.1 5.2 3.8 7.4 6.6 4.8 6.9 2.9 4.5 6.6 2.9 2.4

Stone

Length (In.) 0.9 1.2 1.5 1.2 1.4 0.9 1.0 1.6 0.9 1.4 1.0 1.3 1.7 1.0 1.3

Width (In.) 0.9 1.3 1.5 1.3 1.5 1.0 1.0 1.6 0.9 1.4 1.0 1.3 1.8. 1.0 1.2

Weight (Gins/fruit) 53 73 74 69 71 33 33 43 55 81 43 64 56 41 46
z

Red Purple Red Red Red Red/Yellow Yellow/Red Purple Purple Red Yellow Methley Fl-i Red Red Morris Red Red Ozark Premier Red/Yellow Yellow Robusto Red Red Santa Rosa Red Yellow Santa Rosa A-il Red Yellow Segundo Red Red Red Yellow Shirley
*l 1=cling, 1O=free.

Crimson Explorer Frontier Frontier M- 1 Homeside Methley Methley B-20

Red Red/Purple Red

(Pct.) 13.6 13.4 10.3 13.3 14.2 13.6 12.5 15.2 13.9 13.5 12.1 13.0 17.9 12.3 13.5

r

y

hd

r r

b

r z
y

y

O

FIG. 1. Bloom Dates for North Alabama
Cultivar CB-68 CB-15 AU-Amber AU-Roadside B rongold Bruce 12-4 Homeside AU-Producer
Methle

February 23 24 25 26 27 28

1

2

3

4

5

6

7

8

9 10

March 11 12 13 14 15

16 17

18 19 20

AU-Cherry Auburn #1 Crimson Ozark Premier Segundo AU-Rubrum CB-28 Morris Robusto AU-Rosa Explorer Methle B-20 Frontier M-1 CB-71 CD-90

FIG. 2. Bloom Dates for Central Alabama
February Cultivar CB-28 CB-15 CD-90 23 24 25 26 27 28 1 2 3 4 5 6 7 8 9 10 March 11 12 13 14 15 16 17 18 19 20

B ron old Segundo Frontier M-1 Robusto Bruce 12-4 CB-68 Santa Rosa AU-Rosa AU-Amber AU-Producer CB-71 Frontier Methle AU-CherrHomeside AU-Roadside Explorer Ozark Premier Auburn #1 Morris Crimson Methle B-20 AU-Rubrum Shirley

FIG. 3. Bloom Dates for South Alabama
February Cultivar 23 24 25 26 27 28 Frontier M-1 Mariposa M-1 B rurigold CB-15 CB-28 Segundo AU-Producer AU-Rosa Bruce 12-4 Explorer Homeside Methle Robusto AU-Amber AU-Rubrum Auburn #1 AU-Cherry AU-Roadside CB-68 Methle 8-20 Morris Crimson Ozark Premier 1 2 3 4 5 6 7 8 9 March 10 11 12 13 14 15 16 17 18 19 20

Frontier

FIG. 4. Harvest Dates for North Alabama
May June
2 6 7 8 9 10G1 12 131415 16 17 19 2021 223 24 25~?62 825 i 23 1 S6789111

July
1 13 14 1516

Cultivar
AU-Amber CD-90 Mehtley Robusto Segundo Auburn #1 Morris AU-Rosa AU-Rubrum AU-Producer

28 29 3031 1

Foairk PrMier HU-omside B 15nol

FIG. 5 Harvest Dates for Central Alabama
May 28293031 1 Cultivar Shirley AU-Amber Methley B-20 Robusto AU-Rubrum Morris Metnley Segjndo Auburn #1 Crimson AU-Rosa Santa Rosa Frontier CB-63 AU-Producer CB-71 AU-Roadside Bruce 12-4 Exp rer Ozark Premier Frontier M-1 AU-Cherry CB-15 CD-90 Homeside Byron old CB-8 June July

2 3 4 5 6 7 8 9 101112131415161718 192021 222324252627282930 1 2 3 4 5 6 7 8 91011 1213141516171819

FIG. 6. Harvest Dates for South Alabama
June Gultivar Methley Segundo Robusto AU-Rubrum AU-Amber Crimson Auburn #1 Morris Methley B-20 AU-Rosa Ozark Premier GB-68 AU-Producer AU-Roadside Bruce 12-4 Frontier M-1 B ron old AU-Cherry CB-15 CB-28 Homeside Mari osa M-1 Ex lorer Frontier
.10111 111415161718192021 222324252627282930 1

July
2 3 4 5 6 7 8 9 10111213141516171819202122232425 2627 28

PLUM

VARIETY

TRIALS

21

REFERENCES
(1) Lipe, J.A. 1979. Plum Variety Performance and Quality in East Texas. Prog. Rep., Texas Agr. Exp. Stat. No. PR-3556. (2) Matta, F.B., R.C. Sloan, Jr., and O.P. Vadhwa. 1994. Performance of Japanese Plum Cultivars in Northern Mississippi. Fruit Var. J. 48:89-93. (3) Norton, J.D. 1973. Crimson and Purple - Two Disease Resistant Plums for the Commercial Market. Agr. Exp. Stat. Auburn Univ. Lflt. 85. (4) Norton, J.D. 1975. Homeside: An Excellent Quality Plum for Home and Roadside Market. Agr. Exp. Stat. Auburn University. Circ. 218. (5) Norton, J.D., J.M. Snell, D.A. Smith, and K.S. Rymal. 1984. AURoadside: An Excellent Quality Plum for Home Use and Local Markets. Agr. Exp. Stat. Auburn Univ. Circ. 271. (6) Norton, J.D., G.E. Boyhan, D.A. Smith, and B.R. Abrahams. 1989. AU-Amber: An Excellent Quality Plum for the Early Market. Agr. Exp. Stat. Auburn Univ. Circ. 199. (7) Norton, J.D., G.E. Boyhan, D.A. Smith, and B.R. Abrahams. 1989. AU-Cherry Plum Cultivar Developed for Home Garden Production. Agr. Exp. Stat. Auburn University. Circ. 305. (8) Norton, J.D., G.E. Boyhan, D.A. Smith, and B.R. Abrahams. 1990. New Early Season Plum Developed -- AU-Rubrum Cultivars Combined High Yielding Ability with Disease Resistance and Excellent Fruit Quality. Agr. Exp. Stat. Auburn University. Circ. 301. (9) Norton, J.D., G.E. Boyhan, D.A. Smith, and B.R. Abrahams. 1990. AU-Rosa Plum Developed: Mid-season, High Yielding, and Disease Resistance Cultivar Produces Excellent Fruit. Ag. Exp. Stat. Auburn Univ. Circ. 304. (10) Okie, W.R., J.M. Thompson, C.C. Reilly, F.I. Meredith, J.A. Roberton, B.G. Lyon. 1992. "Segundo," "Byrongold," and "Rubysweet" Plums and BY69-1637P Plumcot-Fruits for the Southeastern United States. Fruit Var. J. 46:102-107. (11) Weinberger, J.H. 1975. Plums, 336-347. In: J. Janick and J.N. More (eds.) Advances in Fruit Breeding. Purdue Univ. Press, West Lafayette, Ind.

Alabama's Agricultural Experiment Station System AUBURN UNIVERSITY

With an ariealtiral
mt~jor soil area.

FRNI

1f 1~

Auburn Unfi\ rcit

4

wLD
EFRO

f ield crop, liv estock, forestry' and ho it iC ltuiral
pr oducers ini each

IEN

TUCAASERCLY

AIOP

RS

regiion ini Alahamna.
Ex ery citizen of the7 state has a stake insg t his rescarch program,.LSL sintce tiny ads anta cc fromi nevw and more ax econoi cal way
itt pr oducing andA~n

EN

'L6g

1
1

.0

handling tarmn products directly bentefits the 11tIn11iiiii pnlilC. CL

A-

sflG
F

15)
'A~y1

OEU
GNV

16"
SO

189

I't'tt vrch I nil Idenv~tificationl

Main Agricultural Experiment Station, Auhurn E. V. Smith Research Center, Shorter.
Tennessee Valley Substationr Belle Mina. Sand Mountain Substationr Cronsville North Alabama Horticulture Snbstation, Cullman. Upper Coastal Plain Subostation Wintield. Forestry Unit. Fayette Countly Chilton Atea Horticnlture Substation, Clanton. Forestry Unit. Coosa County. Piedmont Substation, Carrp Hill. Foresty Unit, Autauga County. Prattville Enperiment Field. Prattvillie 1.Black Belt Sabstation. Marion Ju.nction. 12. The Tu~rnipseed- Ikenobetry Place, Union Springs. 13. Lower Coastal Plain Substation, Camden. 4 Forestry Unit, Barbonr County. t5S Monroeville Enperimeet Field, Monroeille. t6. Wiregrass Subhstation, Headland. 17. Brewton Enperirment Field. Brewton. 18 Ornamental Horticiulture Subhstation, Spring Hill. 19. ulf Coast Substation, Fairhope.