University of California

Variations in citrus seedlings and their relation to rootstock selection


H. J. Webber

Author Affiliations

H. J. Webber was Professor of Subtropical Horticulture in the Experiment Station.

Publication Information

Hilgardia 7(1):1-79. DOI:10.3733/hilg.v07n01p001. June 1932.

PDF of full article, Cite this article


Abstract does not appear. First page follows.

Although the question of securing the best rootstocks to use in citrus propagation has for many years attracted the attention of growers, experimentation on the subject has been very limited. The earliest general publication on citrus stocks in America, that of (Van Deman (1891)), is a summary of the observations and studies made on groves in Florida and is not based on comparative experiments. (Mills (1902)) has described the results of certain experiments conducted by the California Experiment Station at Pomona, California; and (Bonns and Mertz (1916)), the results of a series of comparative experiments made at the Citrus Experiment Station at Riverside.

A carefully planned and executed experiment was also carried out for a limited time by (Taber (1904)) at Glen St. Mary, Florida, with certain varieties propagated on Trifoliate orange, sour orange, and sweet orange. The experiment was designed primarily to determine the comparative value of the cold-resistant Trifoliate orange as a stock.

As a result of these studies and experiments and of the cumulative understanding of growers derived from long experience, certain stocks have come to be commonly used, and success in general has been achieved with them. It is well recognized, however, that the problems connected with rootstocks are poorly understood, and there is little evidence to justify a conclusion that the species and varieties now used as stocks are the best available. A fair appreciation of the value of sour orange, sweet orange, lemon, grapefruit, and certain other species as stocks has been acquired, but until recently no attention has been directed to variations within these species and the influence of such variations on the fruit or scion variety. Until recently this was also the case in the propagation of all other commercial fruits, such as the apple and pear.

The experiments herein reported, which were started in 1914 (Webber, 1919) and (1920), resulted in directing attention to the great variability among seedlings of the same species or stock type, and to the probable influence of such variation on the uniformity of the orchard trees produced. The present paper will outline the results obtained with these experiments up to the present time, and will discuss briefly the influence that the findings may have in improving nursery methods in the future.


Amos J., Hatton R. G., Hoblyn T. N., Knight R. C. The effect of scion on root. II. Stem worked apples. Jour. Pomol. and Hort. Sci. 1930. 8:248-258.

Batchelor L. D., Parker E. R., McBride Robert. Studies preliminary to the establishment of a series of fertilizer trials in a bearing citrus grove. California Agr. Exp. Sta. Bul. 1928. 451:1-49.

Bioletti Fredric T. Selection of planting stock for vineyards. Hilgardia. 1926. 2:1-23.

Blackman V. H. The compound interest law and plant growth. Ann. Bot. 1919. 33:353-360.

Bonns W. W., Mertz W. M. Experiments with stocks for citrus. California Agr. Exp. Sta. Bul. 1916. 267:275-301.

Brown W. Robertson. The orange: a trial of stocks at Peshawar. Agr. Research Inst. Pusa, India Bul. 1920. 93:1-6.

Burkholder C. L., Green Laurenz. Influence of size of mahaleb seedlings on nursery grades. Amer. Soc. Hort. Sci. Proc. 1929. 26:96-97.

Collison R. C., Harlan J. D. Variability and size relations in apple trees. New York State Agr. Exp. Sta. Tech. Bul. 1930. 164:1-38.

Frost Howard B. Polyembryony, heterozygosis and chimeras in citrus. Hilgardia. 1926. 1:365-402.

Haas A. R. C., Halma F. F. Chemical relationship between scion and stock in citrus. Plant Physiology. 1929. 4:113-121. DOI: 10.1104/pp.4.1.113 [CrossRef]

Hatton R. G. Paradise apple stocks. Jour. Royal Hort. Soc. 1917. 42:361-399.

Mills J. W. Citrus fruit culture. California Agr. Exp. Sta. Bul. 1902. 138:1-46.

Oppenheim J. D. The selection of citrus trees, its importance and problems. Hadar [Palestine Citrograph]. 1931. 3:274-276. and 4: 4-7.

Osawa I. Cytological and experimental studies in citrus. Jour. Col. Agr. Imp. Univ. Tokyo. 1912. 4:83-116.

Parker E. R., Batchelor L. D. Variations in the yields of fruit trees in relation to the planning of future experiments. 1932. Hilgardia. (In press.)

Roberts R. H. Some stock and scion observations on apple trees. Wisconsin Agr. Exp. Sta. Res. Bul. 1929. 94:1-39.

Sax Karl. Nursery stock investigations. Amer. Soc. Hort. Sci. Proc. 1924. 211:310-312.

Sax Karl. Bud and root selection in the apple. Maine Agr. Exp. Sta. Bul. 1928. 344:21-32.

Sax Karl, Gowen John W. The relation of tree type to productivity in the apple. Maine Agr. Exp. Sta. Bul. 1922. 305:1-20.

Sax Karl. The place of stocks in the propagation of clonal varieties of apples. Genetics. 1923. 8:458-465.

Shamel A. D., Scott L. B., Pomeroy C. S. Citrus-fruit improvement, a study of bud variation in the Washington Navel orange. U. S. Dept. Agr. Bul. 1918. 623:1-146.

Strasburger E. Über Polyembryonie. Jenaische Zeitsch. f. Naturwiss. 1878. 12:654

Swarbrick Thomas, Roberts R. H. The relation of scion variety to character of root growth in apple trees. Wisconsin Agr. Exp. Sta. Res. Bul. 1927. 78:1-23.

Taber G. L. Fruitfulness of the orange on Trifoliate, sweet and sour. 1904. Florida: Jacksonville. p. 209-218. Quoted in: Hume, H. Harold, Citrus fruits and their culture.

Tanaka Yuichiro. The inter-relation between scion and stock in citrus, with special reference to the influence of scion on stock. Studia Citrologica [Edited by Tanaka Citrus Exp. Sta.]. 1931. 4:213-227.

Toxopeus H. J. De polyembryonie von citrus en haar beteekens voor de cultuur. Dep. Landbouw. Algemeen Proefst. Korte Meded No. 1930. 8:1-15. Also in Landbouw (Buitenzorg) Jrg. 6 4 1930-31.

Van Deman H. E. Relative merit of the various stocks for the orange. U. S. Dept. Agr. Div. Pomology Bul. 1891. 4:1-25.

Vyvyan M. C. The effect of scion on root. III. Comparison of stem and root-worked trees. Jour. Pomol. and Hort. Sci. 1930. 8:259-282.

Webber H. J. Complications in citrus hybridization caused by polyembryony. Science n.s. 1900. 11:308-309. DOI: 10.1126/science.11.282.827 [CrossRef]

Webber H. J. Work of the United States Department of Agriculture on plant hybridization. Jour. Roy. Hort. Soc. [London]. 1900a. 24:128-138.

Webber H. J. Notes on citrus hybrids. Amer. Breeders’ Assoc. Ann. Rept. 1905. 1:78-86.

Webber H. J. Influence of character of stock on citrus tree growth. California Citrograph. 1919. 5:35

Webber H. J. Selection of stocks in citrus propagation. California Agr. Exp. Sta. Bul. 1920. 317:267-301.

Webber H. J. The improvement of root-stocks used in fruit propagation. Jour. Heredity. 1920a. 11:291-299.

Webber H. J. The relation of stocks to scions with special reference to citrus. Amer. Soc. Hort. Sci. Proc. 1922. 19:129-139.

Webber H. J. Citrus root-stock problems. California Citrograph. 1922a. 7:391 408-411

Webber H. J. The lemon root-stock problem. California Citrograph. 1926. 11:374 398-401

Webber H. J. Root-stock reactions as indicating the degree of congeniality. Amer. Soc. Hort. Sci. Proc. 1926a. 23:30-36.

Webber H. J. The citrus root-stock problem in California. California Citrograph. 1928. 14:50 74-76

Webber H. J. The basis of selection in the improvement of citrus nursery stock. Amer. Soc. Hort. Sci. Proc. 1930. 27:114-119.

Webber H. J., Barrett J. T. Root-stock influence in citrus. 1930. p. 358-373. Proc. IX Internatl. Hort. Congress, London

Webber H. J., Swingle W. T. New citrus creations of the Department of Agriculture. U. S. Dept. Agr. Yearbook. 1905. 1904:221-240.

Woglum R. S. Fumigation investigations in California. U. S. Dept. Agr. Bureau Ent. Bul. 1909. 79:1-73.

Webber H. 1932. Variations in citrus seedlings and their relation to rootstock selection. Hilgardia 7(1):1-79. DOI:10.3733/hilg.v07n01p001
Webmaster Email: wsuckow@ucanr.edu