these studies increased row spacing or reduced seeding rates had no effect on seed yield (Helps 1971; Kondra 1975, \97'7; Bengtsson 1978;Singh and Yusuf 1978

Changes in hypocotyl length, cotyledon weight, lipid content, chlorophyll content, and capacity for photosynthesis have been described in seedlings of Citrullus vulgaris, Schrad. (watermelon)

. 2007. Yield and quality of canola seed as affected by stage of maturity at swathing. Can. J. Plant Sci. 87: 13-26. Swathing is an important canola (Brassica napus L.) harvest operation in western Canada. The determination of the optimum timing for this operation is worth considering, as premature swathing may lead to reduced seed yield and quality. Seed yield and quality of three canola cultivars (44A89, AC Excel and Ebony), as affected by two seeding dates and several harvest times (six or eight swathing times and one direct combined treatment) was investigated on a Black Chernozem silty loam soil at Melfort, Saskatchewan, Canada, during 1998, 2000and 2001. Seed yield, weight, protein content (oil-free meal basis) and oil content generally increased with seed development and swathing time. Early seeding was more conducive to achieving higher seed yield, especially in good growing conditions, and resulted in heavier mature seeds with higher oil content. Seed oil composition also changed during seed development. The proportion of oleic (C18:1) and linolenic (C18:3) acids increased, while that of myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), linoleic (C18:2) and arachidic (C20:0) acids decreased. The levels of the long chain fatty acids eicosenoic (C20:1) and erucic (C22:1) acids were unaffected. However, the overall amount of fatty acids synthesized (mg 100 seeds -1 ) increased as seeds matured. Swathing was advantageous over direct combining in preventing weather-induced shattering. . En général, le rendement grainier, le poids, la teneur en protéines (tourteau délipidé) et celle en huile s'améliorent avec le degré de maturité de la graine et le moment où a lieu l'andainage. Des semis hâtifs favorisent un meilleur rendement grainier, surtout quand les conditions de croissance sont propices à cette culture, et donnent des graines plus lourdes et plus riches en huile à maturité. La composition de l'huile évolue également avec le développement de la graine. Ainsi, la proportion des acides oléique (C18:1) et linolénique (C18:3) augmente tandis que celle des acides myristique (C14:0), palmitique (C16:0), palmitoléique (C16:1), stéarique (C18:0), linoléique (C18:2) et arachidique (C20:0) diminue. La concentration des acides gras à chaîne longue comme les acides éicosénoïques (C20:1) et érucique (C22:1) n'est cependant pas affectée. La quantité globale d'acides gras synthétisés (mg par centaine de semences) augmente néanmoins avec la maturité des graines. L'andainage s'avère plus utile que la récolte directe pour prévenir l'égrenage prématuré attribuable aux intempéries.

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