POTENTIAL OF IN-FIELD AND LOW-TEMPERATURE DRYING FOR REDUCING CHLOROPHYLL CONTENTS IN CANOLA (BRASSICA-NAPUS L)

The presence of green seeds in canola arises primarily from the common practice of swathing the crop prematurely in order to hasten the harv esting process and reduce the shattering losses. The purpose of this s tudy was to determine the effects of plant maturity, swathing and dura tion of swathing on moisture and chlorophyll contents of canola seeds (Brassica napus L cv Westar), and to determine the effect of canola co nditioning with air at 25-degrees-C and 90 % RH on chlorophyll content . A standing crop of canola with 50 % to 10 % (w/w) seed moisture cont ent was sampled at regular intervals in two consecutive harvest years (1989 and 1990). Canola was also swathed at three different stages of maturity, and seeds were checked for chlorophyll at 2-3 day intervals and compared with chlorophyll contents of seed from standing crop. Sam ples were conditioned in a thin layer with air at 25-degrees-C and 90 % RH for 24 h, and chlorophyll was determined before and after conditi oning. The chlorophyll of seeds decreased exponentially with a decreas e in moisture content. Conditioning canola seeds decreased chlorophyll content by an average of 16 % (SD = +/- 12 %).