Comparison of morphological traits, productivity and canopy architecture of winter oilseed rape (Brassica napus L.) and white mustard (Sinapis alba L.)

In the years 2006-2008, comparative studies of productivity and plant architecture of open pollinated winter oilseed rape cv. NK Petrol and white mustard cv. Nakielska were undertaken. Morphological traits, including the stem architecture and display of the siliques of both species, were studied. The contribution of the fruiting part of the plant as well as the number of branches with siliques is higher in winter oilseed rape plants, compared to white mustard. The total number of siliques on lateral branches of oilseed rape is also significantly higher than for white mustard. For both species, lateral branches make a greater contribution to the yield of each single plant, but for white mustard this contribution is not as evident as for oilseed rape. Plants of winter rape have about 25% more siliques per stem unit in comparison to white mustard. Winter oilseed rape siliques contain on average 18.5 seeds. The mass of winter oilseed rape seeds per silique is strongly linearly correlated with seed biomass (R-2 = 0.95). However, the length of siliques in these species is poorly correlated with seed mass. The yield of winter oilseed rape is several times higher than that of white mustard; that of a single oilseed rape or white mustard plant is 13.8 g or 2.0 g, respectively. In a single plant of oilseed rape, larger yield is associated with the number of siliques on the lateral branches and further the total yield of a single oilseed rape plant with a predominance of very large, large and medium silique categories based on size. These silique categories constitute 67.7% of the fruits and account for 80.1% of the plant yield. For white mustard small, medium and large siliques predominate, comprising 76.7% of fruits, and account for 78.7% of the total yield.