Journal of Heredity,
12(1): 40-41 (1921)
GROWING TOMATOES BY TIP-CUTTING
GEORGE B. DURHAM
Connecticut Agricultural College, Storrs
THE common garden tomato, Lycopersicum esculentum, a native of Central America, Peru, and the southern parts of the United States, has been known by civilization for several centuries. Although its cultivation as a vegetable dates only to the seventeenth century much progress in breeding has been made since that time.
|1Stevens, A. T. and Durham, G. B. 1917. Tomato Breeding. Unpublished, on file in Hort. Dept., Conn. Agr. College.|
Propagation by all breeders has been by seeds and in a very few cases by cuttings of the terminal buds. In one experiment1 on tip cuttings vs. plants grown from seed, it was shown that with about twenty plants the average production for the tip cuttings was 75 fruits weighing 163.35 ounces, compared with 53 fruits weighing 148.3 ounces for the plants grown from seed. All plants were started at the same time but the plants from the tip cuttings matured fruits one month earlier than those grown from seed.
PROPAGATION BY BUD SPROUTS
While on this problem the writer conceived the idea of propagating by means of the sprouts from adventitious buds which appeared on the leaves of plants that had been cut back and heavily forced.
Cuttings were taken from the variety "Comet" and rooted in a dark, moist chamber. Within ten days from the time the cuttings were taken, they had formed sufficient roots to insure potting. Later these plants were transferred to the regular raised benches and in 116 days from the day that the cuttings were taken the first ripe fruit was picked.
Within five weeks all the fruits had ripened. In a comparison between the leaf cuttings and ten plants each of "Noroton" and "Farquhars Bountiful," planted alternately in the beds, the following results were obtained:
|Av. Total Weight||Av. Weight||Began Bearing||Ended|
|Leaf cutting||34||176.8||ounces||5.2||oz.||June 10||July 22|
|Noroton||74||153.5||"||2.7||"||June 14||Aug. 2|
|Bountiful||43||139.7||"||3.29||"||June 17||July 30|
From these leaf-cutting plants other leaf cuttings were taken. These were budded when cut and matured fruit from the first blossoms. They took about six weeks to mature fruit and the total production per plant was about 20 fruits averaging 2.1 ounces. The plants were grown in cold frames and did not seem to thrive so well as the parent plants, due possibly to change in environment.
From these second generation cuttings other cuttings were taken and grown under the same cultural conditions as the original parent. These cuttings were over four inches long and some were in blossom, one of them having set a fruit. This fruit ripened in 31 days from the time the cuttings were taken and weighed only .8 of an ounce. The other fruits were small averaging 1.3 ounces with less than 15 to a plant.
DEGENERATION AFTER FIRST GENERATION
This the author took as sufficient evidence to show that after the first generation the sacrifice of a number of fruits was not offset by the advantage gained by a shortened growing period.
Microscopic examination of 20 of these leaves showed 56-70 bundles at the junction of the petiole and main stem. Each leaflet or sprout is formed by the separation of 4-7 of these bundles from the series in the main system. These 4-7 bundles break up into 16-28 a short distance from the emergence from the main system. The last leaf left averaged eight bundles at the base and 17 in the middle, breaking up as veins emerge.
Flower buds appear 10-30 days after the emergence of the sprout from the stem. Fertile flowers appear in the first cluster.
While the total production and size of the plants decrease nearly 50% each generation the average number of bundles does not decrease.
Summing up the experiment it seems safe to say that plants from leaf-cuttings in tomatoes show a noticeable increase in production in the first generation of cuttings from the parent plant, but do not warrant consideration commercially in succeeding generations.