Leaf area duration of oilseed rape (Brassica napus subsp. napus) varieties and hybrids and its relationship to selected growth and productivity parameters

The trial with 11 genotypes of winter oilseed rape (Brassica napus subsp. napus) with different provenance was based on experimental station Borovce near SCAR – RICP Piešťany (Slovak Republic) in autumn 2008 (the Trnavská pahorkatina locality, altitude 167 m, maize growing region). Approximately in weekly intervals, since beginning of April to middle of June 2009, for the purpose of growth analysis, plants of all genotypes were taken. The curves of leaf area development of genotypes were simulated from the data on the size of leaf area using software application. Based on these curves, the integral leaf area (leaf area duration, LAD) was established, calculated as the integral area under the curve showing the course of simulated leaf area during the spring growing season. Hybrids had an average leaf area larger than the line varieties. The highest values of LAD reached line varieties Verona and Viking. LAD values simulated for the spring growing season of individual genotypes correlated closely with dry mass weight reached before siliques ripening period (in the middle of June). The positive correlation between the LAD and the number of deployed siliques was recorded. Ability to keep sufficiently large leaf area over a long period expressed in LAD values was shown as a presumption for high production potential of winter oilseed rape genotypes.