Mozliwosci zwiekszenia wydajnosci plantacji nasiennych Lolium perenne

The effectiveness of perennial ryegrass plantations, and hence their profitability, depends, to a considerable extent, on the specificity of the reproduced cultivar. The most appropriate strategy for maintaining high seed yields of new grass cultivars, apart from the improvement of their fodder and lawn aspects, is to seek to obtain the highest seed yield calculated per one generative shoot. In order to increase the efficiency of perennial ryegrass seed plantation it is necessary, apart from the improvement of the seeding aspect of a given cultivar by way of breeding work, also to improve technology of their cultivation. This target can be reached by optimization of agrotechnical factors stimulating biological reproductive potentials of cultivars. Results of own studies indicate that there is an optimal state of nitrogen concentration of perennial ryegrass plants in successive growth stages, which guarantees obtaining the highest seed yields on plantations. In the case of ‘Maja’ cultivar, the content of nitrogen in leaf blades at the beginning of vegetation should amount to 47 g kg⁻¹ DM and at the car initiation - 51 g kg⁻¹ DM. in the case of ‘Anna’ the optimal concentration of nitrogen in leaf blades were 54 and 57 g kg⁻¹ DM, respectively. Another very important factor is the determination of the optimal time and method of harvest as they affect the level of losses of the produced seed yield. The optimal time of seed harvest on perennial ryegrass plantations is the drop of sugars in kernels to the level of 5% DM. The increase of yields from seed plantations of Lolium perenne is a strategic matter for Polish grass seed production, which constitutes an important segment of the domestic seed industry.