Date of Award

1997

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Michael Braverman

Abstract

A three year study was conducted to evaluate the herbicide glufosinate on BAR-transformed rice and on the weed red rice. Preliminary evaluations with 1.1 and 2.2 kg/ha glufosinate on the BAR-transformed Gulfmont and Koshihikari rice varieties showed that both were resistant, but there was more injury to Koshihikari. Glufosinate at 2.2 kg ai/ha injured BAR-transformed Gulfmont rice more when applied to the 1- to 2-leaf stage (23-26%) than when applied to 3- to 4-leaf (13-19%) plants. The damage was least with boot stage applications (3-14%). Phytotoxicity to BAR-transformed Gulfmont rice was greater when 2.2 kg/ha glufosinate was combined with 0.4 kg/ha triclopyr (59%) or 0.6 kg/ha acifluorfen (22%) than with glufosinate alone. Single applications of 1.1 kg/ha glufosinate to the 3- to 4-leaf stage of non-transformed red rice resulted in greater control (91%) than applications at the panicle initiation (74%) or boot stages (77%). Glufosinate efficacy was reduced when red rice was submerged in water to 25 to 50% of its height at application. Red rice was controlled 92% with either 3.4 kg/ha propanil or 0.6 kg/ha acifluorfen mixed with 0.6 kg/ha glufosinate, which was greater than for glufosinate alone and other tested combinations. Greenhouse studies on cross resistance of BAR-transformed Gulfmont rice in comparison to non-transformed Gulfmont rice and red rice showed that injury due to metolachlor, trifluralin, glyphosate, sulfosate, paraquat, and imazethapyr was similar on all rice types. In baseline resistance studies, I$\sb{50}$ values for visual injury of non-transformed Gulfmont and Koshihikari were 0.13 and 0.06 kg/ha, respectively. Ammonia accumulation was greater in Koshihikari than Gulfmont rice. Reciprocal crosses were made in the greenhouse between the BAR-transformed Gulfmont and Koshihikari varieties and non-transformed red rice, to assess the inheritance of the transgene. F$\sb2$ populations segregated as a ratio of 3 (resistant):1 (susceptible), confirming that the glufosinate resistance gene was inserted into a single chromosomal locus or closely linked loci.

ISBN

9780591458473

Pages

128

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