Plant-breeding : comments on the experiments of Nilsson and Burbank

Preface

Under the influence of the work of Nilsson, Burbank, and others, the principle of selection has, of late, changed its meaning in practice in the same sense in which it is changing its significance in science by the adoption of the theory of an origin of species by means of sudden mutations. The method of slow improvement of agricultural varieties by repeated selection is losing its reliability and is being supplanted by the discovery of the high practical value of the elementary species, which may be isolated by a single choice. The appreciation of this principle will, no doubt, soon change the whole aspect of agricultural plant breeding.

Hybridization is the scientific and arbitrary combination of definite characters. It does not produce new unit-characters; it is only the combination of such that are new. From this point of view the results of Burbank and others wholly agree with the theory of mutation, which is founded on the principle of the unit-characters.

This far-reaching agreement between science and practice is to become a basis for the further development of practical breeding as well as of the doctrine of evolution. To give proof of this assertion is the main aim of these Essays.

Some of them have been made use of in the delivering of lectures at the universities of California and of Chicago during the summer of 1906 and of addresses before various audiences during my visit to the United States on that occasion. In one of them (II. D.), the main contents have

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PREFACE been incorporated of a paper read before the American Philosophical Society at their meeting in honor of the bicentennary of the birth of their founder, Benjamin Franklin, April, 1906.

The results of Nilsson have been published only in the Swedish language; those of Burbank have not been described by himself. My arguments for the theory of mutation have been embodied in a German book, “ Die Mutationstheorie” (2 vols. Leipsic, Veit & Co.), and in lectures given at the University of California in the summer of 1904, published under the title of “ Species and Varieties; their Origin by Mutation.” A short review of them will be found in the first chapter of these Essays.

LIST OF ILLUSTRATIONS

Fig.

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A. The Oak-leaved Hazelnut ( Corylus Avellana laciniata), a natural sport of the ordinary hazelnut (B) .

A. The toadflax (. Linaria vulgaris). B, C. Its peloric variety. D. A peloric flower on an ordinary specimen

A. The Double-flowered Corn-marigold ( Chrysanthemum segetum plenum ), an experimental mutation produced at Amsterdam, 1899. B. A flower-head of the original cultivated variety. C. The first result of selection. D. The first sign of doubling. E. A typical double flower-head .

The Experiment Garden in the botanical garden at Amsterdam, covered with iron wire netting. Cultures of different Evening Primroses, some enclosed in bags for artificial pollination, 1904 ......

Lamarck’s Evening Primrose ( Oenothera Lamar ckiana) , a mutating species .......

Leaves of Lamarck’s Evening Primrose (A), and of two of its mutants (B. Oen. lata. C. Oen. scintillans )

Mutants of the Evening Primrose. A. The red-veined form (O. rubrinervis ) which is of the same size as the original species. B. and C. The dwarfish variety (Oen. nanella ) .........

A flower-spike of the giant-mutant ( Oenothera gigas), which originated in my garden, 1896 .....

A flower-spike of the red-veined mutant ( Oenothera rubrinervis), which has been produced almost yearly by the parent species ........

Dr. Hjalmar Nilsson, Director of the Swedish Agricultural Experiment Station at Svalof .....

Poland wheat ( T riticum polonicum) ....

A. Bellevue de Talavera- wheat, isolated by Le Couteur.

B. Bearded white wheat, produced by Patrick Shirreff.

C. Squarehead wheat, the most famous production of the same breeder .......

A. Hallett’s pedigree Chevalier barley. B. Hallett’s pedigree wheat ........

A reproduction of part of the first advertisement of pedigree wheat by F. F. Hallett. See the Times, London, June 18, Nov. 8 and Dec. 19, 1862 ....

The Swedish Agricultural Experiment Station at Svalof. Part of the campus and residence of the Director .

The new building of the Swedish Experiment Station at Svalof, erected 1907. ......

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Fig.

17. The Laboratory of the Agricultural Experiment Station at

Svalof, Sweden .......

18. The Storage building of the Agricultural Experiment Station

Svalof, Sweden .......

19. Svalof Concordia pea, a most productive erect new variety

of green peas, produced at Svalof ....

20. Svalof Pearl Summer wheat, not layering, early ripening,

with full-rounded kernels, that keep in the ears at harvest time ........

21. Ordinary Butt Summer wheat, for comparison with the im-

proved variety of the previous figure .... 22-26. Five different types of new varieties of oats, produced at Svalof. Fig. 22. Flag-oats . . . .

23. Stiff-branched Svalof oats ......

24. Svalof oats with spreading branches

25. Svalof oats with bending branches ....

26. Svalof oats with weak branches .....

27. A. Rye of Schlanstedt, produced by Wilhelm Rimpau by

slow repeated selection. B. Ordinary rye .

28. Determination of centgener power of the progeny of individ-

ual wheat plants at the Agricultural Experiment Station of Minnesota at St. Anthony Park. The progeny of each parent plant packed in a sack for separate harvesting. The Director, Mr. Hays in the first carriage, August, 1904

29. Breeding block of corn which has been bred for high oil

content on the farms of Funk Bros. Seed Co., Bloomington, 111. ...... . .

30. Strength of individual stalks of corn on the breeding blocks

of Funk Bros. Seed Co., Bloomington, 111.

31. Different types of corn. A. King Philipp, a variety of flint

corn. B. Giant yellow dent corn. C. Rice popcorn. D. Dwarf popcorn .......

32. A. Sweet corn, an ear with a staminate upper part and with

some few kernels in top. B, C. Parts of a tassel of flint corn bearing staminate spikelets and kernels

33. A highly ramified ear of corn .....

34. A. A male or staminate spikelet of corn. B. A pair of pis-

tillate or female flowers. After models of Brendel, Berlin

35. A. Tassel of corn, flowering and producing the anthers from

the spikelets. C. Ear in the husks, producing the silks

36. Sweet corn, with scattered starchy kernels, produced by

partial cross-pollination ......

37. Method of sacking ear and tassel in corn for hybridizing,

Agricultural Experiment Station, Manhattan, Kansas

38. The hand pollination of corn in one of the breeding blocks

on the farms of Funk Bros. Seed Co., Bloomington, 111.

39. Another view of hand pollination in breeding blocks of

corn of Funk Bros. Seed Co., Bloomington, 111.

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LIST OF ILLUSTRATIONS

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40. Growth of individual rows of com on the breeding blocks

of Funk Bros. Seed Co., Bloomington, 111. .

41. Rows from cobs of corn which have been self-fertilized and

from those which have not been self-fertilized. The small rows are those self-fertilized. On the breeding blocks of Funk Bros. Seed Co., Bloomington, 111. .

42. Alternate detasseled rows of corn, at a later period of

growth, on the breeding blocks of Funk Bros. Seed Co., Bloomington, 111. . . • • •

43. View in the experiment garden of Amsterdam, with cul-

tures of corn and Evening Primroses ....

44. Twisted stems. A. Of a horsetail ( Equisetum Telmateja).

B. Of the wild teasel ( Dipsac-us sy Ives Iris) .

45. Sterile Corn, a special form of barren stalks without tassel

and without ear. Originated in the botanical garden at Amsterdam, 1888 . ......

46. Sweet corn. A. With straight rows. B. With oblique

47. A kernel of corn cut longitudinally. H, E. Horny endo-

sperm. M, E. Mealy or starchy endosperm. S Scutellum. G, G. Germ. B. The young bud from which the stem will develop. R. Rootlet. After Frank

48. One of the breeding blocks of corn, which is being bred for

high protein on the breeding blocks of Funk Bros. Seed Co., Bloomington, 111. Sept. 1906

49. Luther Burbank of Santa Rosa, Cal. .... 50,, Burbank’s farm at Santa Rosa, Cal., showing the residence,

the greenhouse, the shed, and part of the Experiment garden. Photograph of the S. Pac. R. R. Co. .

51. Experimental garden of Luther Burbank at Santa Rosa.

A spineless cactus is seen along the fence. Cultures of Echeveria and other species in the foreground. Photograph of the S. Pac. R. R. Co. .....

52. Luther Burbank in the garden before his house at Santa

Rosa, Cal., receiving a visit of the author of these Essays (in the middle) and of Dr. G. H. Shull, of the Carnegie Institution (to the right) ......

53. A field of improved Australian Star-flowers on Burbank’s

home farm ........

54. The improved Everlasting Australian Star-flower

55. A Hybrid Walnut reaching double the height of ordinary

trees ( Juglans Calijornica nigra ) ....

56. Extreme variability in the size of seedlings of hybrid wal-

nuts in the second generation ..... 57- A row of hybrid walnuts before the residence of Luther Burbank at Santa Rosa. Photograph of the S. Pac. R. Co. >••*.. * . 1

58. Burbank Giant prune .......

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Fig.

59. Burbank Sugar prune .......

60. The improved stoneless prune. The pit is not surrounded

by any stony material, but by a jelly ....

61. Hybrid Cactus Seedlings at Santa Rosa, 1904 .

62. The Spineless edible Cactus, a hybrid between wild spine-

less species and the cultivated varieties, growing along the fence of Burbank’s farm at Santa Rosa .

63. A row of Shasta-daisies ......

64. A flower-head of the fluted variety of the Shasta-daisy

65. The crisp-leaved hybrid Heuchera ....

66. The crisp-leaved hybrid Heuchera of Burbank. B, C.

Normal type of Heuchera leaves ....

67. Extreme variability in the size of hybrid Callas

68. A. The plum and B. The brown-leaved Prunus Pissardi,

two species grafted on the same tree ....

69. Seedlings of the Spineless edible Cactus in their first and

second years. Most of them are spiny, but the rare spineless ones will be selected for propagation

70. Seedlings of the Spineless edible Cactus in their second year.

71. Extreme variability in the shape of the leaves of hybrid pop-

pies. Second generation from a cross between the Bridevariety of the opium poppy and the Oriental poppy

72. A. The variety the Bride of the opium poppy. B. The

wild species (Papaver pilosum). C. The hybrid of these two poppies ........

73. Flowers of Columbine, showing the spurs

74. The deadly nightshade, or Atropa Belladonna. A. Brown

flower, andB. Black fruit of the species. C. A twig of the yellow variety with pale flowers and yellow fruits

75. The long-leaved Veronica ( Veronica longi folia )

76. The laciniated bramble ( Rubus frnticosus laciniatus), with

divided petals. B. A flower of the ordinary bramble

77. A. Ordinary celandine ( Chelidonium majus). B. Lac-

iniated celandine (C. m. laciniatum) , which originated from A in a garden at Heidelberg about 1590. a and b. Flowers of A and B ......

78. Flowers of Evening Primroses, deprived of the petals. A.

The ordinary species ( Oen . biennis ), a self-pollinating species collected near Chicago. B. Summer-flower of Lamarck’s Evening Primrose, the stigma protruded beyond the anthers. C. A late flower of the same plant with the anthers touching the stigma ....

79. Panicles of oats. A. With erect and B. With spreading

branches ........

80. Svalof Grenadier wheat, the best of the new Swedish varie-

ties of wheat, very productive of grain and straw .

81. Svalof Bore-wheat, a new hardy variety for the cultures of

Middle Sweden .......

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LIST OF ILLUSTRATIONS xi

Fig. Page.

82. A panicle of oats, with weak branches, photographed at

Svalof, Sweden . . . . . . .273

83. A panicle of oats with stiff branches, photographed at

Svalof, Sweden . . . . . . -275

84. A spikelet of oat-grass ( Avena elatior), showing a flower

with two palets, three stamens, and two stigmas (a), a flowerbud (b), of which only the palets are visible, and the third or sterile flower (c) . . . .278

85. Barley. A. A complete spikelet with the three flowers.

B and C. Single flowers seen from different sides, showing two palets, three stamens, and the ovary with the stigmas. In B, also the two outer scales or glumae. D.

Stamens and ovary of a flower . . . . .279

86. Svalof Solo pea, a new forage-plant, most productive of

seeds and foliage. Leaves green . . . .281

87. Svalof Grop pea, a new early ripening forage-plant . . 283

88. The wild oat-grass {Avena elatior), a pasture grass . . 285

89. A pitcher-like leaf of tobacco . . . . .291

90. Pitchers of Magnolia, A, B, C. Of clover, D, E. Of

the lime-tree ( Tilia ), F, G. One-leaved pitchers.

C. Two-leaved. A. Upper part of a leaf only transformed into a pitcher. D, E. Pitcher-like leaflets of

the ordinary and of the five-leaved clover . . . 293

91. A. Seedling-plants of Evening Primroses. B. Of the fig-

wort {Scrophularia nodosa ). C. Of Silene odontipetala.

D. Of poppies. E. Of the beech. A 1 and D 1. Normal seedlings. A 7, B, C 2, D 4, E, Tricotyledonous seedlings. C 3, D 5, Seedlings with four and D 6 with five seed-leaves. A 2-6, C 1, D 2-3, Different degrees

of splitting of seed-leaves ...... 295

92. Polycephaious opium poppy. A. Normal fruit. B. The

same cut longitudinally. C, D. Normal stamens. E, F. Stamens transformed into secondary carpels. G, H, I. Secondary carpels, cut transversely with one, two, and four rows of seeds ....... 299

93. Young plant of opium poppy in the sensitive period of the

development of the terminal flower, cut longitudinally.

A. Flower- head of June 7. B. Of June 14. C. All parts discernible. D. Diagram of flower. E. Diagram of young flowerbud. P. Petals. S. Stamens . . 301

94. The Double Corn-marigold, an experimentally produced

95. Variability in the size of the ripe fruits of the Evening

Primrose of Lamarck. A. A weak plant with small fruits. B. A tall plant with large fruits . . . 305

96. A. The Pansy and some of its parents. B. Viola lutea

grandiflora. C. Viola tricolor versicolor. D. Viola tricolor lutescens. After Wittrock . . . .

xii Fig.

97. Gordon’s currant ( Ribes Gordonianum), a hybrid of the

flowering currant and the golden currant

98. A. The flowering currant of the Pacific coast ( Ribes

sanguineum) . B. The yellow currant ( Ribes aureum ) .

99. A. The cultivated snapdragon. B-G. Its color varieties.

B. Yellow. C. Delila, tube white and lips red. D, E. Flesh-colored. F. Brilliant, of a fiery red. G. Album, white with a yellow spot on the lip. H. The calyx and the style after the removal of the corolla

100. Danebrog Opium poppy ; petals red with a large white spot

at the base ........

101. Glass-covered part of the experiment garden at Amsterdam

in the late spring, 1906; the biennial plants of the Evening Primroses are flowering, the annual specimens are still very small. Tubes for spraying and sacks for artificial pollination .......

102. A. The short-styled Evening Primrose, and B-F, its parent

form. b. A flower after the removal of part of its petals and stamens, c. The same without petals, d. The same without the tube and calyx, e. A flowerbud. /. Ripe fruits. B-F. The corresponding parts of the parent species, g. Styles, h. Longitudinal section of ovary, i. Transversal section of base of style and calyx-tube .........

103. A biennial specimen of the Evening Primrose of Lamarck .

104. A. Spikes with almost ripe fruits of Oenothera gigas, a

mutant species. B. The same of Oenothera Lamarckiana, its parent form ......

105. A. A rosette of root-leaves of Lamarck’s Evening Primrose

in September. B. A similar rosette of one of its mutants (Oen. scintillans ) in the same age ....

106. The smooth-leaved variety of the Evening Primrose ( Oeno-

thera laevifolia), a. A side-flower with ovate instead of obcordate petals, one of the new, highly variable characters of the new form .......

107. Oenothera muricata, a seaside plant which originated far

from the sea ........

108. Wulfenia carinthiaca, which grows almost only on the

Gartnerkugel in Carinthia ......

109. The smooth-leaved campion, a local plant of Bohemia with

a useless character .......

no. Two Alpine species of milfoil. A. The Achillea atrata of calcareous soils. B. The A. moschata of siliciferous soils # .

in. Palo Verde or Parkinsonia microphylla, a typical desert plant from Tucson, Arizona ..... 1 1 2. Palo Christ! or Koeberlinia speciosa, a typical desert plant from Tucson, Arizona ......

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LIST OF ILLUSTRATIONS

Fig.

i 13. A. Forest of giant Cacti (Cereus giganteus ) near Tucson, in Arizona. Opuntia in the foreground. Ocotillo, tree-cactus, and Palo Verde in the middle .

1 14. The desert botanical laboratory at Tucson, Arizona, with two shrubs of Ocotillo ( Fouquieria splendens), giant cacti, Opuntia, tree-cactus, and other shrubs

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COMMENTS ON THE EXPERIMENTS OF NILSSON AND BURBANK

Contents

I. Evolution and Mutation i

II. The Discovery of the Elementary Species of Agricultural Plants by Hjalmar Nilsson.

A. Different Principles in the Breeding of Cereals . . 29