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Abstract
ABSTRACT
Two groups of field experiments were carried out at the Agricultural Experiment and Research Station, Faculty of Agricultural, Cairo University during 2002/2003 and 2003/2004 growing seasons. The 1st group was to study the effect of seeding methods and seeding rates on yielding ability and yield structure of Canola (Brassica napus and Brassica rapa).While the 2nd group was to study the effect sowing and harvesting dates on yield and yield structure of the two Brassica species. The experiments were carried out in a split plot design with 4 and 5 replications in the 1st and 2nd group, respectively. In the 1st group, the main plots were randomly distributed by three seeding methods (broadcasting, drilling in rows 25 cm and 50 cm apart). The sub-plots were devoted to three seeding rates of 1, 2 and 3Kg/fad. In the 2nd group Four Sowing dates (Oct. 12, Oct. 27, Nov. 12 and Nov. 27) that were distributed in the main plots, the sub-plots were devoted to three harvesting dates (the first one was at physiological maturity,) the 2nd and 3rd harvesting dates were at one and two weeks later, respectively. Combined results over seasons revealed that seeding methods had significant effect on seed yield/fad as well as yield/plant and its contributing traits with some exceptions, while seeding rate effects were only significant for yield/plant and its components in addition to seed oil% of B. rapa only. Considering the interaction between the two factors, seeding method appeared to be the major one affecting canola productivity under the present conditions. Drill seeding of both species either in 25 or 50 cm row spacing at any seeding rate produced higher yield/fad than the broadcasting. Highest yield/fad of both species was produced from drilling at 25 cm row spacing combined with 3 Kg/fad seeding rate. At any seeding method yield/plant and its contributing traits significantly decreased as seeding rate increased. High values of these traits were recorded at lower (1 Kg/fad) seeding rate. The interaction had no significant effect on seed oil % for both species. Yield analysis of individual plant showed that the differences in total yield contribution from the main and lateral branches were mostly due to the species. B. napus plants carrying on average more than 90% of total yield/plant on the main and primary branches, while the contribution of secondary branches varied from 0.01 to 9.4% taking into account seeding methods and rates. In contrast, the contribution of secondary branches of B. rapa accounted for 43.5% as a general mean over the two factors of study. Seeding date had significant effect on seed yield/fad as well as yield/plant and its contributing traits with some exceptions. Seeding on Nov. 12 significantly produced the highest seed yield /plant and yield/faddan followed by Oct. 27 without significant differences in B.napus, while it outyielded other seeding dates of B.rapa. Seeding date had no significant effect on seed oil content in B.rapa, while the highest seed oil content obtained when B.napus seeded at Oct. 27 without significant differences with Oct. 12 and November 12. All studied characters were not significantly affected by harvesting date also; the interaction between seeding and harvesting dates was not significant for all traits. The results overall suggest that drill seeding at 25 cm row spacing combined with seeding rate of 3 Kg/fad should be used for production of both B. napus and B. campestris canola. Also both genotypes can be grown successfully in a new crop sequence before any short summer season crop or before cotton based on harvesting canola (B.rapa) at the first of March when it seeded at Oct. 27.