Chemical Control of Pollination in Wheat and Oats1
- R. R. Johnson and
- C. M. Brown2
The objective of this work was to determine if foliar sprays of 3-(p-chlorophenyl)-6-methoxy-s-triazine~2,4-(1H,3H) dione, triethanolamine salt (DPX 3778) were effective pollen control agent for spring oats (Avena sativa L.) and spring wheat (Triticum aestivum L.). The effect of rate and stage of application was examined in green-house and field environments. In the greenhouse, treatment with 9 kg/ha active ingredient of DPX 3778 at the early boot stage essentially prevented seed set on six of 11 spring wheat cultivars that were bagged to prevent outcrossing. Treated plants produced pollen that failed to dehisce from the anthers.
‘Protor’ spring wheat or ‘Noble’ spring oats were treated with 0, 4.5, 9, 18, and 27 kg/ha in the field at different growth stages. Increasing chemical rate decreased plant height and reduced seed set on bagged spikes. DPX 3778 at or above 9 kg/ha on Protor wheat appeared sufficient largely to prevent pollen shed when applied at early or late boot. Testcrosses at the 9 kg/ha rate indicated no noticeable adverse effect on female fertility. Seed set on Noble oats was not totally prevented at any rate although 27 kg/ha reduced seed set to less than 10% of the control when applied at early heading or in a split application at early boot plus early heading. In one experiment phytotoxicity was observed on Noble oats at the 18 and 27 kg/ha rates, but 18 kg/ha did not affect this cultivar in a second experiment.
A field experiment revealed genotypic differences in chemical response. Plant height and pollen shed of wheat cultivars were generally reduced more than in oat cultivars. DPX 3778 delayed anther exsertion and floret opening. A sufficient number of wheat cultivars exhibited adequate pollen control to suggest that DPX 3778 may be of potential use in a wheat breeding program.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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