Summary
Progenies of barley plants taken at random from generations F8, F13, F23, and F45 of Composite Cross II were tested for reaction to three barley pathogens, Helminthosporium teres, Erysiphe graminis, and Rhynchosporium secalis (four races). The frequency of families resistant to each of the three pathogens (excepting one race of R. secalis) increased from early to later generations. Many families carrying combinations of multiple resistance not observed among the parents were found in the later generations; one-half of the parents were susceptible to all three diseases but only 4% of the families in generation F45 were of this phenotype. The frequency of multiply resistant families also increased sharply over generations. Among the parents the greatest concentration of resistant reactions observed was triple resistance: 14% were triply resistant; none were quadruply resistant; nor were any resistant to all three pathogens. In generation F43 36% of the families were triply resistant, 32% were quadruply resistant and 6% were resistant in five of the six disease reactions. The value of later generations of Composite Cross II for breeding against pathogens thus appears to have been increased by recombination and natural selection. Significant positive correlations were found for resistance to races 40, 61, and 74 of R. secalis whereas correlations between resistance to R. secalis, E. graminis, and H. teres were generally nonsignificant. Use of these multiply resistant genotypes in breeding is thus unlikely to be hindered by negative associations between resistance to the three diseases.
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References
Ali SM, Matfield AH, Clare RG (1976) Pathogenicity of 203 isolates of Rhynchosporium secalis on 21 barley cultivars. Physiol Plant Pathol 9:135–143
Allard RW, Jain SK (1962) Population studies in predominantly self-pollinated species. 2. Analysis of quantitative genetic changes in a bulk-hybrid population of barley. Evolution 16:90–101
Bird LS (1982) The MAR (multi-adversity resistance) system for genetic improvement of cotton. Plant Dis 66:172–176
Bockelman HE, Sharp EL, Eslick RF (1977) Trisomic analysis of genes for resistance to scald and net blotch in several barley cultivars. Can J Bot 55:2142–2148
Harlan HV, Martini ML (1929) A composite hybrid mixture. J Am Soc Agron 21:487–490
Jackson LF, Webster RK (1976) Race differentiation, distribution, and frequency of Rhynchosporium secalis in California. Phytopathology 66:719–725
Jackson LF, Kahler AL, Webster RK, Allard RW, (1978) Conservation of scald resistance in barley composite cross populations. Phytopathology 68:645–650
Moseman JG (1966) Genetics of powdery mildews. Ann Rev Phytopathol 4:269–290
Muona O, Allard RW, Webster RK (1982) Evolution of resistance to Rhynchosporium secalis (Oud.) Davis in barley composite cross II. Theor Appl Genet 61:209–214
Schaller CW (1951) The effect of mildew and scald infection on yield and quality of barley. Agron J 43:183–188
Singh S (1962) Biotic factors effecting barley net blotch epidemiology. Indian Phytopathol 15:195–202
Webster RK, Jackson LF, Schaller CW (1980) Sources of resistance in barley to Rhynchosporium secalis. Plant Dis 64:88–90
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Communicated by H. F. Linskens
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Saghai Maroof, M.A., Webster, R.K. & Allard, R.W. Evolution of resistance to scald, powdery mildew, and net blotch in barley composite cross II populations. Theoret. Appl. Genetics 66, 279–283 (1983). https://doi.org/10.1007/BF00251159
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DOI: https://doi.org/10.1007/BF00251159