TY JOUR TI RELATIONSHIP OF YIELD OF VARIETIES OF COMPETITIVE VARIETY TESTING OF SPRING SOFT WHEAT WITH ELEMENTS OF ITS STRUCTURE IN THE MIDDLE VOLGA REGION KW spring common wheat (Triticum aestivum L.) KW principal component method KW crop structure elements. JO Vestnik of Kazan State Agrarian University AU Menibayev, A.I. PY 2023 IS 17 PB Kazan state agrarian University