Bulletins, Circulars, Progress Reports

Circular 271

May 1984

Alabama Agricultural Experiment Station

Gale A. Buchanan,
Director

Auburn University

Auburn, Alabama

 

AU- ROADSIDE

AN EXCELLENT QUALITY PLUM FOR HOME USE AND LOCAL MARKETS

J.D. NORTON, J.M. SNELL, D.A. SMITH, and K.S. RYMAL

Professor, Research Associate, Associate Professor, and Associate Professor, respectively, Department of Horticulture.

TABLE OF CONTENTS
 

Introduction

Pedigree of AU-Roadside plum

Disease resistance

Fruit quality

Yields

Storage

Outstanding Characteristics

Availability of Trees

Acknowledgements

INTRODUCTION

     
          AU-ROADSIDE is a new plum variety developed by the Alabama Agricultural Experiment Station, Auburn University, for growing in areas where sufficient chilling of 700 hours of temperature below 45°F occurs. AU-Roadside has proven its ability to produce high yields of excellent quality fruit where there are certain fruit and tree disease problems. The new variety is superior to the Ozark Premier variety in yield, fruit quality, tree vigor, disease resistance, and tree longevity. Therefore, AU-Roadside is being released as a direct replacement for the Ozark Premier variety.
         AU -Roadside was selected from a cross between Ozark Premier and Methley varieties. The cross was made in 1965 and the seedling was tested as Ozark Premier F -2, see figure. It has resistance or tolerance to black knot, bacterial canker, bacterial fruit spot, and plum leaf scald, prevalent diseases of plum, tables 1 and 2. Such resistance is particularly important in the Southeast where prevalence of these diseases and susceptibility of commercial varieties has discouraged plum production. Its resistance to bacterial and fungal diseases came from the Ozark Premier parent, while excellent fruit quality was inherited from both parents.
         Trees of AU-Roadside are vigorous, spreading with dark green leaves.
PEDIGREE OF
AU-ROADSIDE PLUM
Pedigree of AU-Roadside plum.

DISEASE RESISTANCE AU-Roadside is highly resistant to bacterial canker (Pseudomonas syringae, Van Hall), bacterial fruit spot [Xanthomonas pruni (E. F. Smith), Dows], bacterial leaf spot (X. pruni) and black knot (Dibotryon morborsum), tables 1 and 2. A tolerance to plum leaf scald is also present in the trees, table 1.
FRUIT QUALITY

      Fruits of AU-Roadside have dark red (currant red, HCC 46A)1 skin and flesh. Fruit quality is excellent for fresh market which makes the variety adaptable for home, roadside, and local markets. Fruits were rated acceptable in canned fruit tests, table 3. Fruit have adequate firmness for handling, packing, and shipping to commercial markets, table 4. Maturity date is about 1 week before Ozark Premier, table 5. The plant is self fruitful, flowers profusely, and sets a heavy crop.

YIELDS

        The new variety has been in trials as Ozark Premier F -2 at several locations of the Alabama Agricultural Experiment Station system and in grower trials. It compares favorably with other varieties in yield. Production has been highest in central and southeast Alabama, table 6. Average yields of marketable fruit per tree were 122.2 pounds and 117.4 pounds, respectively, from 3- and 4-year-old trees.

STORAGE

         Fruits of AU -Roadside store as well as Homeside and Methley, and better than Bruce and Ozark Premier, table 7.

OUTSTANDING CHARACTERISTICS

         Two characteristics, tree vigor and tolerance to plum leaf scald, delineate the primary improvements of AU-Roadside over Ozark Premier. Trees of AU-Roadside are vigorous and show only traces of plum leaf scald, whereas trees of Ozark Premier grow much slower and are highly susceptible to plum leaf scald. Tree vigor is a primary selective criterion in the Southeast, and the relationship of plum leaf scald to phony peach makes resistance important.
         Three other characteristics, ripening date, growing season, and skin color at maturity, may be taken collectively as another important advantage of AU-Roadside. AU-Roadside ripens 9 days earlier, has a shorter growing season by 7 days, and is more fully colored at any comparable stage of maturity than Ozark Premier, table 5.
         Another improvement of AU-Roadside over Ozark Premier is the increased tree longevity of AU-Roadside. In test orchards at five Alabama locations and at Byron, Georgia, trees of AU-Roadside were in extremely healthy condition.

AVAILABILITY OFTREES

         Trees of AU-Roadside should be available from wholesale and retail nurseries for planting in the winter of 1984-85. A limited supply of bud wood may be obtained from J. D. Norton, Department of Horticulture, Auburn University, Alabama 36849.

ACKNOWLEDGMENTS

         The author gratefully acknowledges the essential assistance of H. M. Bryce, Main Station, and C.C. Carlton and K.C. Short, Chilton Area Horticulture Substation, Clanton, in evaluation and propagation of the varieties.
        Valuable assistance was rendered by M. H. Hollingsworth, North Alabama Horticulture Substation, Cullman; E. L. Mayton (retired),W.A. Griffey, and H.E. Burgess, Piedmont Substation, Camp Hill; J. G. Starling and H. W. Ivey, Wiregrass Substation, Headland; and E. L. Carden and F. B. Selman, Gulf Coast Substation, Fairhope.
        The assistance of J.M. Thompson, Geneticist, USDA Tree Fruit and Nut Laboratory, Byron, Georgia, in evaluating the seedling is deeply appreciated.
        Assistance of growers in conducting commercial grower trials with the material is deeply appreciated.

1 Horticulture Color Chart; Royal Horticulture Society, London.