Short communication. Harvest stage effects on forage yield and quality for rape and turnip genotypes

The effects of two different harvest stages (full flowering and full podding) on forage yield and quality of ten forage rape (Brassica napus L. var. oleifera) and three turnip (Brassica rapa L. var. rapa) cultivars were evaluated under rainfed conditions in a Mediterranean type climate at Bursa, Turkey, during the 2002/2003 and 2003/2004 growing seasons. Plant height, branches per plant, leaf length and width, plant part components, and dry matter (DM) and crude protein (CP) yield were measured. Significant differences were observed for the main effects cultivar and harvest stage on DM and protein yields. The CP content of the whole plant and vegetative parts of the Brassica genotypes decreased as plant maturity progressed. In general, turnip cultivars showed better performance in DM yield. Fall sown turnip produced 9.10 and 12.1 Mg ha DM yield, with 15.1 and 9.10% CP concentrations, at full flowering and at podding stage, respectively. Signif icant differences were noted among cultivars for these two parameters. Protein content decreased dramatically in stem parts when maturity advanced from full flower to full pod stages. High leaf percentage and high protein content at full flowering suggest that this should be the preferred forage harvest stage for rape and turnip cultivars. Additional key words: Brassica napus L. var. oleifera, Brassica rapa L. var. rapa, crude protein, dry matter yield, plant proportions.