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" Selection, characterization and genetic analysis of wheat (Triticum aestivum L.) lines tolerant to grass controlling herbicides "
M. Akram
C. F. Konzak
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1112426
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| Doc. No
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TLpq304010830
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| Main Entry
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C. F. Konzak
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M. Akram
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| Title & Author
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Selection, characterization and genetic analysis of wheat (Triticum aestivum L.) lines tolerant to grass controlling herbicides\ M. AkramC. F. Konzak
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| College
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Washington State University
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| Date
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1992
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| student score
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1992
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| Degree
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Ph.D.
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| Page No
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97
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| Abstract
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Spring wheat (Triticum aestivum L.) Pavon 76 anther culture derived calli induced on potato 4 (P4) liquid medium and regenerated on modified MS medium were used to select for plant tolerance to the herbicides sethoxydim and fluazifop. Anther-derived embryogenic wheat callus cultures were selected for tolerance against sethoxydim and fluazifop using a two step selection procedure at increasing herbicide concentrations in culture media. This two-step selection procedure resulted in a higher proportion of tolerant plants compared to a one-step selection procedure. Radiation treatments to spikes at mid-to-late uninucleate stage did not increase plant regeneration or dihaploid percentage from anther calli. However, a significantly higher number of fluazifop tolerant lines were derived from the radiation treatments. Radiation treatment had no effect on the yield of sethoxydim tolerant plants. The survival percentage of the selected mutants was initially variable among spike progenies from the selected anther derived plants due to chimerism of the calli from which they came, and heterozygosity of mutants in diploidized but stabilized after reselection for 1 to 2 generations. Four sethoxydim tolerant lines, S4-5, S10-6, S42-1, and S43-6 showed 100% tolerance against the standard field dose of 0.112 kg/ha sethoxydim, whereas none of the fluazifop tolerant lines were as tolerant to the field dose of fluazifop. Of the 54 sethoxydim tolerant lines selected, four (S3-1, S4-5, S10-6, and S43-4) appeared to carry cross-tolerance to fluazifop at 1 or 2 times the field dose (0.056 kg/ha). Tests on the F of crosses among the herbicide tolerant lines and between tolerant lines and the control showed that tolerance is dominant and simply inherited, while the F2 segregations of tolerant x tolerant crosses investigated to date showed that the mutations are independently inherited, with possible additive, epistatic, or complementary interactions responsible for the increased levels of tolerance observed in recombinants. Some of the mutations involved may be located in different wheat genomes. The genetic interactions among tolerance genes appear to offer the potential that commercially effective, levels of herbicide tolerance can be recovered from among recombinants of crosses between the most tolerant of lines. The incorporation of tolerance to one or other of these herbicides by backcrossing should be useful for post-emergence control of grassy weeds in spring and winter wheats.
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Agronomy
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Biological sciences
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