| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Dep. of Agronomy and Plant Genetics
Dep. of Agronomy and Plant Genetics and Plant Molecular Genetics Inst., Univ. of Minnesota, St. Paul, MN 55108
* Corresponding author (rasmu002{at}maroon.tc.umn.edu).
Breeding programs in major crops normally restrict the use of parents to those improved for a variety of traits. Gain from utilizing these good x good crosses appears to be high, and improvements are sufficient to encourage continued breeding within narrow gene pools even though each cycle is expected to lead to reduced genetic variability. These finely tuned programs have gradually limited the amount of new diversity introduced into the breeding gene pool. This breeding strategy has led to a genetic gap where there is a large difference in the favorable gene frequency between the improved and unimproved lines and to a narrowing of genetic diversity within elite gene pools. At the same time, evidence has accumulated in plant breeding programs and long-term selection experiments in several organisms that the genome is more plastic and amenable to selection than previously assumed. In the barley (Hordeum vulgare L.) case study reported here, incremental genetic gains were made for several traits in what appears, based on pedigree analysis, to be a narrow gene pool. Given this situation, we call for an examination of the generally held belief that the variation on which selection is based in elite gene pools is provided almost exclusively from the original parents. Classical and molecular genetic analyses have shown that many mechanisms exist to generate variation de novo, such as gene amplification and transposable elements. Accordingly, we put forward the hypothesis that newly generated variation makes an important contribution. We also hypothesize that gene interaction, epistasis, is more important than commonly viewed and that it arises from de novo generated diversity as well as the original diversity.
Received for publication June 5, 1996.
This article has been cited by other articles:
|
|
 |
|
  M. A. Mikel and F. L. Kolb Genetic Diversity of Contemporary North American Barley Crop Sci., July 1, 2008; 48(4): 1399 - 1407. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. F. de Alencar Figueiredo, C. Calatayud, C. Dupuits, C. Billot, J.-F. Rami, D. Brunel, X. Perrier, B. Courtois, M. Deu, and J.-C. Glaszmann Phylogeographic Evidence of Crop Neodiversity in Sorghum Genetics, June 1, 2008; 179(2): 997 - 1008. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Condon, C. Gustus, D. C. Rasmusson, and K. P. Smith Effect of Advanced Cycle Breeding on Genetic Diversity in Barley Breeding Germplasm Crop Sci., May 1, 2008; 48(3): 1027 - 1036. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. A. Fasoula and H. R. Boerma Intra-Cultivar Variation for Seed Weight and Other Agronomic Traits within Three Elite Soybean Cultivars Crop Sci., February 6, 2007; 47(1): 367 - 373. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. L. Phillips Genetic Tools from Nature and the Nature of Genetic Tools Crop Sci., September 8, 2006; 46(5): 2245 - 2252. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. S. Tokatlidis, I. N. Xynias, J. T. Tsialtas, and I. I. Papadopoulos Single-Plant Selection at Ultra-Low Density to Improve Stability of a Bread Wheat Cultivar Crop Sci., December 2, 2005; 46(1): 90 - 97. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. J. Yun, L. Gyenis, P. M. Hayes, I. Matus, K. P. Smith, B. J. Steffenson, and G. J. Muehlbauer Quantitative Trait Loci for Multiple Disease Resistance in Wild Barley Crop Sci., October 27, 2005; 45(6): 2563 - 2572. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. W. Podlich, C. R. Winkler, and M. Cooper Mapping As You Go: An Effective Approach for Marker-Assisted Selection of Complex Traits Crop Sci., September 1, 2004; 44(5): 1560 - 1571. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Yu and R. Bernardo Changes in Genetic Variance during Advanced Cycle Breeding in Maize Crop Sci., March 1, 2004; 44(2): 405 - 410. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Smale, M. P. Reynolds, M. Warburton, B. Skovmand, R. Trethowan, R. P. Singh, I. Ortiz-Monasterio, and J. Crossa Dimensions of Diversity in Modern Spring Bread Wheat in Developing Countries from 1965 Crop Sci., November 1, 2002; 42(6): 1766 - 1779. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. F. Troyer and T. R. Rocheford Germplasm Ownership: Related Corn Inbreds Crop Sci., January 1, 2002; 42(1): 3 - 11. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. D. Peel and D. C. Rasmusson Improvement Strategy for Mature Plant Breeding Programs Crop Sci., September 1, 2000; 40(5): 1241 - 1246. [Abstract] [Full Text]
|
|
|
|
|
|
E. Igartua, M. Edney, B.G. Rossnagel, D. Spaner, W.G. Legge, G J. Scoles, P.E. Eckstein, G.A. Penner, N.A. Tinker, K.G. Briggs, et al. Marker-Based Selection of QTL Affecting Grain and Malt Quality in Two-Row Barley Crop Sci., September 1, 2000; 40(5): 1426 - 1433. [Abstract] [Full Text]
|
|
|
|
|
|
K. B. Hellewell, D. C. Rasmusson, and M. Gallo-Meagher Enhancing Yield of Semidwarf Barley Crop Sci., March 1, 2000; 40(2): 352 - 358. [Abstract] [Full Text]
|
|
|
|
|
|
L.T. Evans and R.A. Fischer Yield Potential: Its Definition, Measurement, and Significance Crop Sci., November 1, 1999; 39(6): 1544 - 1551. [Abstract] [Full Text]
|
|
|
|
 |
|
 M. Lee Genome projects and gene pools: New germplasm for plant breeding? PNAS, March 3, 1998; 95(5): 2001 - 2004. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Schoen, J. L. David, and T. M. Bataillon Deleterious mutation accumulation and the regeneration of genetic resources PNAS, January 6, 1998; 95(1): 394 - 399. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Vadose Zone Journal | |||
| Journal of Natural Resources and Life Sciences Education |
Soil Science Society of America Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||
