engleski

Seed yield of Italian ryegrass as influenced by nitrogen fertilization and plant growth regulator

Croatian farmers have a lack of knowledge about agricultural practices and operations for seed production of Italian ryegrass (Lolium multiflorum Lam.). Thus, the main aim of this study was to evaluate the effect of nitrogen (N) fertilization and plant growth regulator (PGR) application on the seed yield and other traits of Italian ryegrass crop grown for seed production. Field experiment was conducted in northwestern Croatia over two growing seasons with the four N fertilization rates (0, 60, 120 and 180 kg ha-1) and PGR application (Moddus 250 EC applied during stem elongation at the rate of 1.0 L ha-1 along with the unsprayed plots). Growing year significantly affected seed yields as well as all other investigated traits. As expected, Italian ryegrass crop produced higher seed yields in the first growing year by an average of 5.2%. Compared to the unsprayed plots, the application of PGR reduced stem height, and in turn, improved seed yields by an average of 27.0% (383 kg ha-1). Nitrogen fertilization significantly increased seed yields mainly due to increased spike number and heavier 1000 seed weight. Seed yields following N fertilization rates of 120 and 180 kg ha-1 were slightly larger than those produced with 60 kg ha-1. However, a significant N fertilization × PGR interaction was found for seed yield, which indicated that crop responses to N fertilization rates were influenced by the application of PGR. Neither N fertilization nor PGR had an effect on germination rate, but seed viability was higher with heavier seeds.

Italian ryegrass ; Plant growth regulator ; N fertilization ; Seed yield

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