B. Dyulgerova Agricultural Academy, Institute of Agriculture – Karnobat, 8400 Karnobat, Bulgaria (Manuscript received 29 April 2026; accepted for publication 26 August 2026) e-mail: bdyulgerova@abv.bg Abstract. This study aimed to establish relationships among grain yield, prote

M. Gerdgikova, M. Videva, D. Pavlov Abstract. The effect of cultivating two predecessor varieties: (i) wheat and (ii) Triticale, on the content and yield of crude protein from winter pea variety “Mir” is tested during 2005-2007. The study is conducted at Trakia University, Stara Zagor