CORN HYBRIDS AND THEIR PARENTAL FORMS RESPONSIVENESS TO NITROGEN FERTILIZERS
In this work we analyzed the responsiveness to nitrogen fertilizer of two mid-ripening hybrids (FAO 350) and their parental forms – Mashuk 350 MV (AB (A × B) × C) and Mashuk 355 MV (DE (D × E) × C). To understand the genetic determination of responsiveness characteristic to fertilizer we applied genealogical approach in which, if the hybrid and parental components included in his pedigree, that have the same level of characteristic manifestation, a hypothesis of genotypic similarity is set up. Evaluating the effectiveness of nitrogen fertilizer was carried out in such economically valuable traits as yield of green mass and grain. The results of four years research have shown that a large effect on yield increase of green mass and grain of hybrids and inbred corn lines from fertilizer have weather conditions during the growing season. However, there are differences between hybrids and their original forms on responsiveness to nitrogen. The greatest increase in the yield of green mass and grain the nitrogen fertilizer provided at the three-way cross corn hybrid Mashuk 355 MV and its parental forms. On average for 2012-2015 the green mass increase in the hybrid Mashuk 355 MV accounted for 13%, its parental form (DE) – 16%,parental forms of the hybrid DE (D and E) – 18 and 14%. The green mass growth of a hybrid Mashuk 350 MV accounted for 10%, the parental form (AB) – 12%, its basic lines: A – 11%, B – 12%. The grain yield increase from the nitrogen in basic forms of three-way cross Mashuk 355 MV (DE, D, E) was 10%, that is far above the increases of parental forms of hybrid Mashuk 350 MV (AB (3%), A (0,3%), B (3%)). A study of the reaction of mid-ripening corn hybrids to nitrogen fertilizer found that the efficient use of nitrogen by a hybrid depends on the responsiveness of its parental components.