Phenological phases of buckwheat (Fagopyrum esculentum Mnch.) in the primary and secondary crop depending on seeding rate

This paper presents the growth stages of buckwheat grown as a primary or secondary crop as well as using three seeding rates. A field experiment was conducted in the years 2003-2004 and in 2006 on podzolic soil derived from slightly loamy sand. Phenological observations were made at 5-day intervals, from the time of buckwheat emergence (in the primary crop around 28 May, in the secondary crop 7 June), on selected and properly marked plants. The buckwheat plants were harvested when more than 80% of buckwheat seeds on them were brown. The duration of particular growth stages of buckwheat are presented in phenological diagrams. It was found that crop rotation treatment and weather conditions affected significantly the time of occurrence of the phenological phases of buckwheat, but these phases were less dependent on seeding density. A rainfall deficit in 2006 caused a delay in particular growth stages compared to the previous years.