Shading and Thinning Effects on Multi- and Standard-Floret Winter Wheat
- P. E. Jedel and
- L. A. Hunt
Grain set in a crop is related to many factors, including genotype and assimilate supply. This study was conducted to examine differences in grain set in two winter wheat (Triticum aestivum L.) cultivars differing in spike characteristics. The multiflorous cultivar Benni and the standard floret cultivar Houser were investigated in field studies at Elora and Woodstock, Ontario, Canada. In 1984, three 50% of full daylight shading treatments were imposed (FRE: a 2 wk period prior to anthesis; POST: 2 wk following anthesis; FRE + POST: 2 wk prior to anthesis plus the 1 wk following anthesis). In 1985, a postanthesis thinning treatment (THIN), in which stem number was reduced by 50%, was added. In 1984, Houser had reduced total aboveground biomass and grain yields per meters squared with the FRE and FRE + POST treatments. Grain yield reduction was associated with reduced kernel number per meters squared. For Benni in 1984, shading treatments affected neither total biomass nor grain yield. In 1985, all shading treatments reduced total biomass and grain yield for Houser, while treatments FRE and FRE + POST reduced total biomass and treatments FRE + POST and THIN reduced grain yield for Benni. Grain yield reduction for Houser was associated with reduced kernel weight for all treatments and reduced kernel and spike numbers per meters squared for treatment FRE + POST. Reduced grain yield for Benni was associated with reduced kernel numbers for treatments FRE + POST and THIN and spike numbers for treatment FRE + POST. The responses, usually manifest in a similar aboveground biomass production under different shade conditions, suggest that some internal limitation was present.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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