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SELECTION and QUANTITATIVE CHARACTERS IN FIELD CROPS
J. T. WALKER,
J. T. WALKER
Scottish Plant Breeding Station, Pentlandfield, Roslin, Midlothian
Search for more papers by this authorJ. T. WALKER,
J. T. WALKER
Scottish Plant Breeding Station, Pentlandfield, Roslin, Midlothian
Search for more papers by this authorSummary
1. It is vital that there should be no decrease in the rate of improvement of crop plants. In drafting the background to the inheritance of quantitative characters it is suggested that greater understanding of genetic mechanisms is needed rather than further increase in biometrical complexity. Selection is a very powerful force; it could be used to conserve genetic variation whilst effecting useful change.
2. Various breeding techniques, examined in a framework of directional, stabilizing and disruptive selection, are found to be tied to certain crops. Breeders of self-fertilizing plants handle quantitative variation differently from those working with outbreeders.
3. Physiological analysis and partitioning of characters have not in themselves made large contributions to solving problems caused by complex traits, but both have been informative in conjunction with biometrical studies. In some circumstances more use could profitably be made of selection indices.
4. Heterozygote advantage and genetic balance play major parts in stabilizing selection. Modal selection can sometimes lead to increased fitness, conforming with the concept of genetic homeostasis.
5. Disruptive selection has apparently operated during the evolution of crop plants. To be beneficial to breeders it should be multidirectional; intercrossing of peripheral lines might then form ‘springboard’ populations allowing further advance from selection plateaux.
6. As the boundaries of cultivation are extended so the need will increase for plant populations with inherent stability of performance. Few crops are yet amenable to the production of F1 hybrid seed, so polygenes should be manipulated to form balanced, heterozygous adaptive complexes. Systems of selection must be refined to deal effectively with the heterogeneous populations from which such complexes are likely to arise.
7. Studies on composite crosses and related projects tie in well with other work on selective forces in adaptation. New allopolyploids offer hope in some plant groups, but induced mutation is of restricted value.
8. Cryptic variation and selection can be important in many breeding methods, and should be considered when dealing with quantitative aspects.
9. Changes in locality can reveal startling amounts of unsuspected variability: such ‘environmental segregation’ could be harnessed, for example, by alternation of selection centres when breeding for general adaptability.
10. Persistence of variation, which may occur through selection favouring hetero-zygotes despite strict inbreeding, is also considered in terms of heterozygous gene complexes. Tightness of linkage is the key to the durability and behaviour of super-genes, and analysis of the simpler ones could lead to better understanding of the vastly complicated systems controlling fitness and productivity.
References
- Aastveit, K. (1961). Studies on quantitative characters and quantitative inheritance in barley. Meld. Norg. LandbrHeisk, 40, no. 23, 1–112.
- Allard, R. W. (1960). Principles of plant breeding. New York : Wiley.
- Allard, R. W., Harding, J. & Wherhahn, C. (1966). The estimation and use of selective values in predicting population change. Heredity 21, 547–63.
- Arnold, M. H. (1963). The control of bacterial blight in rain-grown cotton. I. Breeding for resistance in African Upland varieties. J. agric. Sci., Camb. 60, 415–27.
-
Arnold, M. H. &
Brown, S. J. (1968). Variation in the host-parasite relationship of a crop disease.
J. agric. Sci., Camb.
65, 19–36.
10.1017/S0021859600065540 Google Scholar
- Arnold, M. H., Walker, J. T. & Morris, D. A. (1962). Prog. Rep. Exp. Stas, Uganda, 1961–2, pp. 10–14. Empire Cotton Growing Corporation.
- Bell, G. D. H. & Kirby, E. M. J. (1965). Utilization of growth responses in breeding new varieties of cereals. Proc. XIIth Easter School in agric. Sci., University of Nottingham (ed. F. L. Milthorpe and J. D. Ivins), pp. 308–19.
- Bennett, E. (1965). Plant introduction and genetic conservation: genecological aspects of an urgent world problem. Scottish PI. Breed. Sta. Rec. 1965, pp. 27–113.
- Bickoff, E. M. (1968). Oestrogenic constituents of forage plants. Review no. 1/1968, Commonwealth Agricultural Bureaux.
- Bodmer, W. F. & Parsons, P. A. (1962). Linkage and recombination in evolution. Adv. Genet. 11, 1–100.
- Borlaug, N. E. (1959). The use of multilineal or composite varieties to control airborne epidemic diseases of self-pollinated crop plants. Proc. First Int. Wheat Genet. Symp. pp. 12–26.
-
Breese, E. L. &
Mather, K. (1957). The organization of polygenic activity within a chromosome in Drosophila. I. Hair characters.
Heredity
11, 373–95.
10.1038/hdy.1957.30 Google Scholar
- Briggs, F. N. (1926). Inheritance of resistance to bunt Tilletia tritici (Bjerk.) Winter, in wheat. J. agric. Res. 32, 973–90.
-
Briggs, F. N. (1930). Breeding wheats resistant to bunt by the backcross method.
J. Am. Soc. Agron.
22, 239–44.
10.2134/agronj1930.00021962002200030004x Google Scholar
-
Brim, C. A.,
Johnson, H. W. &
Cockerham, C. C. (1959). Multiple selection criteria in soybeans.
Agron. J.
51, 331–4.
10.2134/agronj1959.00021962005100060008x Google Scholar
- CHandRaratna, M. F. (1964). Genetics and breeding of rice. London : Longmans, Green.
-
Compton, W. A.,
Lonnquist, J. H. &
Gardner, C. O. (1964). Predicted response to recurrent selection with intra- and inter-varietal testers in corn (Zea mays L.).
Crop Sci.
4, 146–8.
10.2135/cropsci1964.0011183X000400020006x Google Scholar
- Comstock, R. E., Robinson, H. F. & Harvey, P. H. (1949). A breeding procedure designed to make maximum use of both general and specific combining ability. Agron. J. 41, 360–7.
- Cooper, J. P. (1960). Selection for production characters in ryegrass. Proc. VIIIth Int. Grassl. Congr. pp. 41–4.
-
Cooper, J. P. (1963). Species and population difference in climatic response. In Environmental control of plant growth (ed.
L. T. Evans), pp. 381–403.
New York
: Academic Press.
10.1016/B978-0-12-244350-3.50025-2 Google Scholar
- Cooper, J. P. (1965a). The use of physiological variation in forage-grass breeding. Proc. XIIth Easter School in agric. Sci., University of Nottingham (ed. F. L. Milthorpe and J. D. Ivins), pp. 293–307.
- Cooper, J. P. (1965b). The evolution of forage grasses and legumes. In Essays on crop plant evolution (ed. J. B. Hutchinson), pp. 142–65. Cambridge University Press.
- Dobzhansky, TH. (1951). Genetics and the origin of species. New York : Columbia University Press.
- Doggett, H. (1965a). The development of the cultivated sorghums. In Essays on crop plant evolution (ed. J. B. Hutchinson), pp. 50–69. Cambridge University Press.
- Doggett, H. (1965b). Disruptive selection in crop development. Nature, Lond. 206, 279–80.
- Doggett, H. & Majisu, B. N. (1968). Disruptive selection in crop development. Heredity 23, 1–23.
- Dyte, C. E. (1967). Possible new approach to the chemical control of plant feeding insects. Nature, Lond. 216, 298.
- East, E. M. (1916). Studies on size inheritance i. Nicotiana. Genetics 1, 164–76.
- Edwards, A. W. F. (1963). Migrational selection. Heredity 18, 101–6.
- ELLERSTROum, E. & Josefsson, E. (1967). Selection for low content of rhodanidogenic glucosides in fodder rape. Z. Pflanzenzuchtg. 58, 128–35.
-
Engledow, F. L. &
Wadham, S. M. (1923). Investigations on yield in the cereals. I.
J. agric. Sci., Camb.
13, 390–439.
10.1017/S0021859600003828 Google Scholar
- Falconer, D. S. (1960). Introduction to quantitative genetics. Edinburgh : Oliver and Boyd.
-
Finlay, K. W. &
Wilkinson, G. N. (1963). The analysis of adaptation in a plant-breeding programme.
Aust. J. agric. Res.
14, 742–54.
10.1071/AR9630742 Google Scholar
-
Fisher, R. A. (1930). The genetical theory of natural selection. Oxford University Press.
10.1890/0012-9658(2006)87[1445:SOEFDD]2.0.CO;2 Google Scholar
- Fisher, R. A. (1936). The use of multiple measurements in taxonomic problems. Ann. Eugen. Lond. 7, 179–89.
- Fisher, R. A. (1949). The theory of inbreeding. Edinburgh : Oliver and Boyd.
- Frankel, O. H. (1950). The development and maintenance of superior genetic stocks. Heredity 4, 89–102.
- Frankel, O. H. (1966). Adaptability of crops. New Scient. 29, 144–5.
- Fraser, A. S. (1962). Simulation of genetic systems. J. theor. Biol. 2, 329–46.
- Fryxell, P. A. (1956). A genetic analysis of yield in Upland cotto (Gossypium hirsutum). Iowa St. Coll. J. Sci. 30, 361. (Abst.).
- Gibson, J. B. & Thoday, J. M. (1962). Effects of disruptive selection VI. A second chromosome polymorphism. Heredity 17, 1–26.
- Gibson, J. B. & Thoday, J. M. (1963). Effects of disruptive selection VIII. Imposed quasi-random mating. Heredity 18, 513–24.
- Grant, V. (1958). The regulation of recombination in plants Cold Spring Harb. Symp. quant. Biol. 23, 337–03.
- Greer, M. A. (1962). The natural occurrence of goitrogenic agents. Recent Progr. Horm. Res. 18, 187–219.
- Gregory, W. C. (1956). Induction of useful mutations in the peanut. Brookhaven Symp. Biol. 9, 177–90.
-
Griffing, B. (1960). Theoretical consequences of truncation selection based on the individual pheno-type.
Aust. J. biol. Sci.
13, 307–43.
10.1071/BI9600307 Google Scholar
- Hanson, W. D. & Johnson, H. W. (1957). Methods for calculating and evaluating a general selection index obtained by pooling information from two or more experiments. Genetics 42, 421–32.
- Harlan, J. R. (1956). Distribution and utilization of natural variability in cultivated plants. Brook-haven Symp. Biol. 9, 191–208.
- Harlan, H. V. & Martini, M. L. (1938). The effects of natural selection in a mixture of barley varieties. J. agric. Res. 57, 189–200.
- Harlan, H. V., Martini, M. L. & Stevens, H. (1940). A study of methods in barley breeding. Tech. Bull. U.S. Dep. Agric. no. 720, pp. 1–25.
-
Harlan, H. V. &
Pope, M. N. (1922). The use and value of back-crosses in small grain breeding.
J. Hered.
13, 319–22.
10.1093/oxfordjournals.jhered.a102237 Google Scholar
- HARLand, S. C. (1934). Rep. Summ. Proc. Hnd Conf. Cotton Breeding Problems. London : Empire Cotton Growing Corporation.
-
HARLand, S. C. (1936). Haploids in polyembryonic seeds of Sea Island cotton.
J. Hered.
27, 229–31.
10.1093/oxfordjournals.jhered.a104214 Google Scholar
- HARLand, S. C. (1944). The selection experiment with Peruvian Tanguis cotton. Bull. Inst. Cotton Genet., Lima 1, 1–98.
- Harfer, J. L. (1965). The nature and consequence of interference amongst plants. Proc. XIth Int. Congr. Genet. (1963), vol. 11, pp. 465–82.
- Haskell, G. (1956). Heterosis in seedling plants. Proc. R. Soc. B 144, 221.
-
Hayes, H. K. &
Garber, R. J. (1919). Synthetic production of high protein corn in relation to breeding.
J. Am. Soc. Agron.
II, 309–18.
10.2134/agronj1919.00021962001100080001x Google Scholar
- Hayes, J. D. (1959). Varietal resistance to spray damage in barley. Nature, Lond. 183, 551–2.
- Hayman, B. I. (1954a). The theory and analysis of diallel crosses. Genetics 39, 789–809.
- Hayman, B. I. (1954b). The analysis of variance of diallel tables. Biometrics 10, 235–44.
- Hayward, M. D. (1967). The genetic organization of natural populations of Lolium perenne. II. Inflorescence production. Heredity 22, 105–16.
- Hayward, M. D. & Breese, E. L. (1964). Population studies in ryegrass. Rep. Welsh Plant Breeding Stn, 1963, pp. 33–6.
- Hazel, L. N. & Lush, J. L. (1942). The efficiency of three methods of selection. J. Hered. 33, 393–9.
-
Heslop-Harrison, J. (1964). Forty years of genecology.
Adv. Ecol. Res.
2, 159–247.
10.1016/S0065-2504(08)60332-3 Google Scholar
- Hull, F. H. (1945). Recurrent selection for specific combining ability in corn. J. Am. Soc. Agron. 37, 134–45.
- Hutchinson, J. B. (1940). The application of genetics to plant breeding. I. The genetic interpretation of plant breeding problems. J. Genet. 40, 271–82.
- Hutchinson, J. B. (1958). Genetics and the improvement of tropical crops. Cambridge University Press.
- Hutchinson, J. B. (1959). The application of genetics to cotton improvement. Cambridge University Press.
- Innes, N. L. (1966). Promising selections from Albar A (57) 12 in the Sudan. Emp. Cott. Gr. Rev. 43, 263–72.
- Jain, S. K. (1961a). Stabilizing selection for heading time in a bulk-hybrid population of barley. Nature, Land. 191, 1123–4.
- Jain, S. K. (1961b). The composite cross bulk population method. Euphytica 10, 315–24.
- Jain, S. K. & Allard, R. W. (1960). Population studies in predominantly self-pollinated species. I. Evidence for heterozygote advantage in a closed population of barley. Proc. natn. Acad. Sci. U.S.A. 46, 1371–7.
- Jain, S. K. & Allard, R. W. (1965). The nature and stability of equilibria under optimizing selection. Proc. natn. Acad. Sci. U.S.A. 54, 1436–43.
- Jain, S. K. & Allard, R. W. (1966). The effects of linkage, epistasis, and inbreeding on population changes under selection. Genetics 53, 633–59.
-
Jenkins, M. T. (1940). The segregation of genes affecting yield of grain in maize.
J. Am. Soc. Agron.
32, 55–63.
10.2134/agronj1940.00021962003200010008x Google Scholar
- Jinks, J. L. (1954). The analysis of continuous variation in a diallel cross of Nicotiana rustica varieties. Genetics 39, 767–88.
-
Jinks, J. L. (1955). A survey of the genetical basis of heterosis in a variety of diallel crosses.
Heredity
9, 223–8.
10.1038/hdy.1955.21 Google Scholar
- Jinks, J. L. & Mather, K. (1955). Stabilty in development of heterozygotes and homozygotes. Proc. R. Soc. B 143, 561–78.
- Johannsen, W. L. (1903). Uber Erblichkeit in Populationen und in reinen Leinen. Jena : Gustav Fischer.
- Johannsen, W. L. (1926). Elemente der exakten Erblichkeitslehre. Jena : Gustav Fischer.
- Johnson, H. W., Brim, C. R. & Cockerham, C. C. (1956). The use of selection indices in soybean breeding. Am. Soc. Agron. meeting, Cincinnati, Ohio (Abst.).
- Johnston, T. D. & Jones, D. I. H. (1966). Variations in the thiocyanate content of kale varieties. J. Sci. Fd Agric. 17, 70–1.
-
Justus, N. (1960). Residual heterozygosity in a variety of Upland cotton as measured by Micronaire, lint percent, percent first harvest, and yield of lint.
Agron. J.
52, 555–9.
10.2134/agronj1960.00021962005200100001x Google Scholar
-
Karpechenko, G. D. (1928). Polyploid hybrids o Raphanus sativa L. × Brassica oleracea L. Z. indukt. Abstamm.
VererbLehre
39, 1–7.
10.1007/BF01740955 Google Scholar
- Kempthorne, O. (1957). An introduction to genetic statistics. New York : Wiley.
- Knight, R. L. (1954). Cotton breeding in the Sudan. I. Egyptian cottons. Emp. J. exp. Agric. 22, 68–80.
- Knight, R. L. (1957). Blackarm disease of cotton and its control, p. 53. Plant Protection Conference, 1956. London : Butterworth.
-
Knight, R. L. &
Clouston, T. W. (1939). The genetics of blackarm resistance. I. Factors B1 and B2.
J. genet.
38, 133–59.
10.1007/BF02982168 Google Scholar
-
Konzac, C. F. (1954). Stem rust resistance in oats induced by nuclear radiation.
Agron. J.
46, 538–40.
10.2134/agronj1954.00021962004600120002x Google Scholar
- Koelle, G. (1966). Der Nikotin-Abbau des Tabaks, ein Beitrag zur Wirkungweise gleichsinniger Gen. Z. Acker- u. PflBau. 55, 375–82.
-
Kuspira, J. &
Unrau, J. (1957). Genetic analysis of certain characters in common wheat using whole chromosome substitution lines.
Can. J. Plant Sci.
37, 300–26.
10.4141/cjps57-037 Google Scholar
- Lamp, C. A. (1963). The agricultural significance of goitrogenic activity i Brassicae. J. Aust. Inst, agric. Sci. 29, 8–13.
- Langridge, J. (1962). Genetic and molecular basis for heterosis in Arabidopsis an Drosophila. Am. Nat. 96, 5–27.
- Lee, B. T. O. & Parsons, P. A. (1968). Selection, prediction and response. Biol. Rev. 43, 139–74.
- Lerner, I. M. (1950). Population genetics and animal improvement. Cambridge University Press.
- Lerner, I. M. (1954). Genetic homeostasis. Edinburgh : Oliver and Boyd.
- Lupton, F. G. H. (1961). Varietal differences in some physiological characters of wheat. Ann. appl. Biol. 49, 557–60.
- Lupton, F. G. H. (1966). Translocation of photosynthetic assimilates in wheat. Ann. appl. Biol. 57, 355–04.
- Lupton, F. G. H., Ali, M. A. M. & Subramaniam, S. (1967). Varietal differences in growth parameters of wheat and their importance in determining yield. J. agric. Sci., Camb. 69, 111–23.
- Lush, J. L. (1943). Animal breeding plans. Ames : Iowa State College Press.
- Lush, J. L. (1949). Heritability of quantitative characters in farm animals. Proc. VIIIth Int. Congr. Genet. (1948), pp. 356–75.
- Mackey, J. (1956). Mutation breeding in Europe. Brookhaven Symp. Biol. no. 9, pp. 141–56.
- Manning, H. L. (1955). Response to selection for yield in cotton Cold Spring Harb. Symp. quant. Biol. 20, 103–10.
-
Manning, H. L. (1956). Yield improvement from a selection index technique with cotton.
Heredity
10, 303–22.
10.1038/hdy.1956.29 Google Scholar
- Manning, H. L. (1963). Realized yield improvement from twelve generations of progeny selection in a variety of Upland cotton. Statist. Genet. Plant Breed. NAS-NRC Publ. no. 982, pp. 329–51.
-
Mather, K. (1943). Polygenic inheritance and natural selection.
Biol. Rev.
18, 32–64.
10.1111/j.1469-185X.1943.tb00287.x Google Scholar
- Mather, K. (1953). The genetical structure of populations. Symp. Soc. exp. Biol. no. 7, Evolution, pp. 66–95.
- Mather, K. (1955a). Response to selection Cold Spring Harb. Symp. quant. Biol. 20, 158–65.
- Mather, K. (1955). Polymorphism as an outcome of disruptive selection. Evolution 9, 52–61.
- Mather, K. (1956). Polygenic mutation and variation in populations. Proc. R. Soc. B 145, 293–7.
- Mather, K. (1960). Genetics pure and applied. The 5th Bateson Lecture, John Innes Institute.
- Mather, K. (1966). Variability and selection. Proc. R. Soc. B 164, 328–40.
- Mather, K. (1967). Complementary and duplicate gene interactions in biometrical genetics. Heredity 22, 97–103.
- Mather, K. & Harrison, B. J. (1949). The manifold effect of selection. Heredity 3, 1–52, 131–62.
-
Mcgill, D. P. &
Lonnquist, J. H. (1955). Effects of two cycles of recurrent selection for combining ability in an open-pollinated variety of corn.
Agron. J.
47, 319–23.
10.2134/agronj1955.00021962004700070010x Google Scholar
- Mcwilliam, J. R. & Griffing, B. (1965). Temperature-dependent heterosis in maize. Aust. J. biol. Sci. 18, 569–83.
- Merritt, N. R. (1967). A new strain of barley with starch of high amylose content. J. Inst. Brew. 73, 583–5.
- Miller, P. A., Williams, J. C., Robinson, H. F. & Comstock, R. E. (1957). Estimates of genetic and environmental variances and covariances in Upland cotton and their implications in selection. Am. Soc. Agron. meeting, Atlanta, p. 56.
- Moll, R. H., Lindsev, M. F. & Robinson, H. F. (1964). Estimates of genetic variances and the level of dominance in maize. Genetics 49, 411–23.
- MUuntzing, A. (1951). Cytogenetic properties and practical value of tetraploid rye. Hereditas 37, 2–84.
-
MUuntzing, A. (1963). A case of preserved heterozygosity in rye in spite of long-continued inbreeding.
Hereditas
50, 377–413.
10.1111/j.1601-5223.1963.tb01915.x Google Scholar
- Opsahl, B. (1956). The discrimination of interactions and linkage in continuous variation. Biometrics 12, 415–32.
- Panse, V. G. & Khargonker, S. A. (1949). A discriminant function for selection of yield in cotton. Indian Cott. Gr. Rev. 3, 179–85.
-
Papa, K. E.,
Williams, J. H. &
Hanway, D. G. (1961). Effectiveness of selection for quantitative characters in the third generation following irradiation of soybean seeds with X rays and thermal neutrons.
Crop. Sci.
I, 87–90.
10.2135/cropsci1961.0011183X000100020002x Google Scholar
- Parsons, P. A. & Bodmer, W. F. (1961). The evolution of overdominance: natural selection and hetero-zygote advantage. Nature, Land. 190, 7–12.
- Penny, L. H., Russell, W. A., Sprague, G. F. & Hallauer, A. R. (1963). Recurrent selection. Stat. Genet. Plant Breed. NAS-NRC Publ. no. 982, pp. 352–67.
- Qureshi, M. R. H. (1961). Breeding for high yield. Indian Cott. Gr. Rev. 15, 225–32.
- Rees, H. (1955). Genotypic control of chromosome behaviour in rye. I. Inbred lines. Heredity 9, 93–116.
-
Rees, H. (1957). Genotypic control of chromosome behaviour in rye. IV. The origin of new variation.
Heredity
11, 185–93.
10.1038/hdy.1957.16 Google Scholar
- Riggs, T. J. (1967). Response to modal selection in Upland cotton in Northern and Eastern Uganda. Cott. Gr. Rev. 44, 176–83.
- Riley, R. & Chapman, V. (1958). Genetic control of the cytologically diploid behaviour of hexaploid wheat. Nature, Lond. 182, 713–15.
-
Robertson, A. (1956). The effect of selection against extreme deviants based on deviation or on homozygosis.
J. Genet.
54, 236–48.
10.1007/BF02982779 Google Scholar
- Sakai, K. (1955). Competition in plants and its relation to selection Cold Spring Harb. Symp. quant. Biol. 20, 137–57.
-
ST Pierre,
C. A., Klinck,
H. R. &
Gauthier, F. M. (1967). Early generation selection under different environments as it influences adaptation of barley.
Can. J. Plant Sci.
47, 507–17.
10.4141/cjps67-091 Google Scholar
- Saunders, J. H., Innes, N. L. & Gunn, R. E. (1963). Resistance to bacterial blight. Prog. Rep. Exp. Stas., Sudan, 1962–3, pp. 38–40. Empire Cotton Growing Corporation.
- Sax, K. (1923). The association of size differences with seed coat pattern and pigmentation i Phaseolus vulgaris. Genetics 8, 552–60.
- Schnell, F. W. (1961). On some aspects of reciprocal recurrent selection. Euphytica 10, 24–30.
- Simmonds, N. W. (1962). Variability in crop plants, its use and conservation. Biol. Rev. 37, 422–65.
- Simmonds, N. W. (1967). Forage crop investigations. Rep. Scott. PI. Breed. Stn, 1966–7, pp. 10–13.
-
Simmonds, N. W. &
Malcolmson, J. F. (1967). Resistance to late blight in Andigena potatoes.
Eur. Potato J.
10, 161–6.
10.1007/BF02364425 Google Scholar
- Simpson, G. G. (1944). Tempo and mode in evolution. New York : Columbia University Press.
- Smith, H. F. (1936). A discriminant function for plant selection. Ann. Eugen., Lond. 7, 240–50.
- Sprague, G. F. (1966). Quantitative genetics in plant improvement. Symposium on plant breeding. Ames : Iowa State University Press (ed K. J. Frey), pp. 315–54.
-
Sprague, G. F. &
Tatum, L. A. (1942). General vs. specific combining ability in single crosses of corn.
J. Am. Soc. Agron.
34, 923–32.
10.2134/agronj1942.00021962003400100008x Google Scholar
-
Suneson, C. A. (1956). An evolutionary plant breeding method.
Agron. J.
48, 188–91.
10.2134/agronj1956.00021962004800040012x Google Scholar
- Suneson, C. A. (1960). Genetic diversity–a protection against plant diseases and insects. Agron. J. 52, 319–21.
- Suneson, C. A. (1963). Breeding techniques–composite crosses and hybrid barley. Proc. First Int. Barley Genet. Symp., Wageningen, pp. 303–8.
- Suneson, C. A. & Stevens, H. (1953). Studies with bulked hybrid populations of barley. Tech. Bull. U.S. Dep. Agric. no. 1067, pp. 1–14.
- Teas, H. (1957). Physiological genetics. Ann. Rev. PI. Physiol. 8, 393–412.
- Thoday, J. M. (1956). Population genetics. Nature, Lond. 178, 843–4.
-
Thoday, J. M. (1959). Effects of disruptive selection. I. Genetic flexibility.
Heredity
13, 187–203.
10.1038/hdy.1959.22 Google Scholar
- Thoday, J. M. (1961). Location of polygenes. Nature, Lond. 191, 368–70.
- Van der Plank, J. E. (1963). Plant diseases: epidemics and control. New York : Academic Press.
- Virtanen, A. I. (1962). Kropferzeugende Substanzen im Kohl und in Futterpflanzen. Umschau 62, 129.
- Waddington, C. H. (1957). The strategy of the genes. London : Allen and Unwin.
- Walker, J. T. (1960). The use of a selection index technique in the analysis of progeny row data. Emp. Cott. Gr. Rev. 37, 81–107.
- Walker, J. T. (1963). Multiline concept and intra-varietal heterosis. Emp. Cott. Gr. Rev. 40, 190–215.
- Walker, J. T. (1964). Modal selection in Upland cotton. Heredity 19, 559–83.
- Walker, J. T. (1968a). Bias in singling cotton seedlings. Cott. Gr. Rev. 45, 175–8.
- Walker, J. T. (1968b). Selection pressure due to hand thinning of seedlings of varietal mixtures. Cott. Gr. Rev. 45, 258–65.
- Walker, J. T. & Merritt, N. R. (1969). Abnormal starch granules in the endosperm of high amylose barley. Nature, Lond. 221, 482–3.
- Watson, D. J. (1952). The physiological basis of variation in yield. Adv. Agron. 4, 101–45.
- Wherhahn, C. & Allard, R. W. (1965). The detection and measurement of the effects of individual genes involved in the inheritance of a quantitative character in wheat. Genetics 51, 109–19.
- Williams, E. J. (1962). The analysis of competition experiments. Aust.J. biol. Sci. 15, 509–25.
- Williams, J. S. (1962). The evaluation of a selection index. Biometrics 18, 375–93.
- Woodworth, C. M., Long, E. R. & Jugenheimer, R. W. (1952). Fifty generations of selection for protein and oil in corn. Agron. J. 44, 60–5.
- Wright, S. (1935). The analysis of variance and the correlations between relatives with respect to deviations from an optimu. J Genet. 30, 243–56.
- Wright, S. (1956). Modes of selection. Am. Nat. 90, 5–24.
- Young, S. S. Y. (1961). A further examination of the relative efficiency of three methods of selection for genetic gains under less restricted conditions. Genet. Res. 2, 106–21.
- Young, S. S. Y. & Weiller, H. (1961). Selection for two correlated traits by independent culling levels. J. Genet. 57, 329–38.
