Effect Of Pre-harvest Application Research Articles

Effect of preharvest applications of glyphosate on the drying, yield and quality of canola

Potential use of preharvest applications of glyphosate in canola (Brassica rapa L.) in western Canada both as a harvest aid and to control weeds prompted this study. Experiments were conducted from 1988 to 1990 at four locations in the region to document the effectiveness of preharvest applications of glyphosate to enhance canola seed and foliage drydown and to measure the effect of such applications on seed yield and quality. Glyphosate was applied in early August to early September at rates of 0.45, 0.90 and 1.70 kg acid equivalent ha−1 to canola with seed moisture contents ranging from 79 to 12%. Seed and foliage moisture drydown were not enhanced by glyphosate treatment. Glyphosate treatments generally had little or no effect on canola seed yields, seed weight, seed germination, green seed content or oil content except when applied when the pods were green and when seed moisture contents were high. Seed/pod moisture was not a reliable indicator of stage of canola development and thus, should not be used alone as an indicator of when preharvest applications of glyphosate can be applied to canola without decreasing seed yield and quality. Key words: Glyphosate, canola, Brassica rapa L., preharvest application, desiccation, seed quality

Effect of preharvest applications of glyphosate on the drying, yield and quality of wheat

In experiments conducted from 1988 to 1990 at four locations in the Parkland zone of western Canada, the drydown of seed and foliage, seed yield, seed quality and baking quality of wheat (Triticum aestivum L.) following preharvest applications of glyphosate were compared with those following windrowing prior to harvest or direct cutting of the standing crop. Glyphosate was applied in late July to early September at rates of 0.45, 0.9 and 1.7 kg acid equivalent ha−1 to wheat with seed moisture contents ranging from 80 to 11%. When compared with a standing crop, all glyphosate treatments applied at seed moisture contents above 25% slightly enhanced the drydown of wheat seed and foliage. Treatments applied at seed moisture contents below 25% had no effect on either seed or foliage drydown. Seed yields were generally greater from plots to which glyphosate was applied than from windrowed control plots, although in one of five experiments the reverse trend occurred. Increasing the rate from 0.45 to 1.7 kg ha−1 had no effect on yield. Windrowing or applying glyphosate to wheat with a seed moisture content of 61% or more reduced yields more than windrowing or applying glyphosate at seed moisture contents below this level. In experiments where the wheat in both control and sprayed plots was direct cut at maturity, average yields decreased as the rate of glyphosate increased from 0 to 1.7 kg ha−1. However, applications at seed moisture of 40% or less, caused little or no yield loss. There was little or no difference in 1000-seed weight, sample density, seed germination and protein content from plots sprayed with glyphosate at seed moisture contents below 40% than from control plots windrowed at the same moisture content or direct cut at maturity. Baking quality was not affected by any of the glyphosate treatments in experiments where the wheat was harvested by direct cutting. Key words: Glyphosate, wheat, desiccation, wheat quality, Triticum aestivum

Effect of pre-harvest applications of ethephon on leaf abscission, fruit drop and constituents of fruit juice in pomegranates

SummaryFive concentrations of ethephon (0, 500, 1000, 1500, 2000 ppm) were applied to Rabbab pomegranate trees 18 days before harvest. With increased ethephon concentrations the percentage soluble solids, pH, vitamin C content and soluble solids to acid ratio of the juice decreased significantly. However, leaf abscission, fruit drop and percentage acid of the juice increased. As the soluble solids to acid ratio is the best single chemical criterion of pomegranate ripening, it was concluded that ethephon applications delayed ripening, and that the observed fruit drop was a direct effect of ethephon rather than fruit ripening.

Effect of Pre Harvest Application of Some Growth Regulators on the Yield and Quality Characteristics of Grape (Vitis vinifera L.)

Present study was undertaken to investigate the relative efficacy of four growth regulators, viz., α-naphthalene acetic acid (NAA), indole-3-acetic acid (IAA), gibberellic acid (GA) and 2,4-Dichlorophenoxy acetic acid (2,4-D) at various concentrations (ppm) on the yield and some other quality characteristics of grape (Zakkao cultivar) at the experimental grape research vine of BCSIR Laboratories, Rajshahi during the period January, 2003 to July, 2004. Yield was found to be increased (33.11 %) by spraying with 05 ppm of 2,4-D as compared to control and other growth regulator treatments. Fruits of treated plants showed increased total soluble solids (20.28 %) and vitamin (23.18 %) than that of untreated one. The titrable acidity (T. A) of fruits (33.01 %) of the treated plants was reduced significantly as compared to control. 
 
 Bangladesh J. Sci. Ind. Res. 42(1), 59-66, 2007