Finer Strawberries Ahead

by GEORGE M. DARROW

IN 1938 E. F. Farlow, like many of his neighbors in eastern Maryland, had to give up growing strawberries. Each spring his plants died soon after growth started. By harvest time only plants on the higher ground were alive. Growers clear across the Northern States were having the same trouble, and the losses were serious.

Research workers who tackled the problem found first that a fungus was the cause. It rotted off the roots of the strawberries. It spread rapidly in cool, wet weather, but not in well-drained soil or in summer. Next, by testing many varieties, men at the Illinois Agricultural Experiment Station discovered that the Aberdeen strawberry was highly resistant to the devastating disease, which was called red stele disease. Never was a crop failure of Aberdeen due to the red stele disease—but the fruit of Aberdeen was too soft to sell in any but local markets, and it usually lacked flavor. The Department and the Maryland Agricultural Experiment Station joined forces. The Aberdeen was crossed with the Fairfax, a firm, high-flavored kind, and with other varieties. We raised thousands of seedlings on red stele-infested soil, retested those that were least affected, and tested the best of the survivors a third time.

On Mr. Farlow's place one selection proved to be productive; it had high flavor and it shipped well. It was named the Temple in 1943. Three years later it had become an important early variety in eastern Maryland, Virginia, and Delaware. Farlow and research workers want still better varieties. So now Farlow is growing several acres of Temple, an acre of seedlings, and about 100 other selections for the Department and the Maryland station for further testing. He and his neighbors have again become strawberry growers. The project is indeed a cooperative one : Research workers in Scotland, where the red stele disease is also serious, others in Illinois, and a research group in Oregon have exchanged both breeding material and ideas with those working in Maryland, all with the same objective, to originate varieties resistant to the red stele disease and adapted to each section of the country.

Another example also will illustrate the aims and methods of plant breeders. For 40-odd years, up to 1940, Klondike, because of its adaptation to the South, was almost the only strawberry grown in Louisiana. But during that time the leaf spot disease had become more and more injurious, until the plants had to be sprayed several times a year. Then research workers at the Louisiana Agricultural Experiment Station crossed Klondike with Blakemore, and got thousands of offspring, which they raised. These seedlings the scientists sprayed with leaf spot spores. All seedlings that developed much leaf spot were thrown away. Only those not injured were retested. But to be a good variety in southern Louisiana, a plant must throw out many runners. Therefore, in the second test, only good producers of runners were saved. They were fruited, and one, later named Klonmore, was found to produce large crops of firm, bright berries of good flavor. Only 4 years after its introduction, more than half of the crop in Louisiana was Klonmore. No spraying was necessary, for leaf spot has left Klonmore alone up to now.

Thus, when the cause of low yields has been determined or when growers need a variety better suited to preserving, shipping, freezing, or another use, or require one with better flavor, we survey the problem and determine which is the best method of breeding to obtain the desired end.

In California, for instance, virus diseases have been especially serious, and varieties healthier than the Marshall have been bred, named, and introduced by the California Agricultural Experiment Station workers.