Responsiveness of maize hybrids and their parental forms to nitrogen fertilizer

In this work, the responsiveness to nitrogen fertilizer of two mid-ripening maize hybrids (FAO 350) and their parental forms—Mashuk 350 MV (AB (A × B) × C) and Mashuk 355 MV (DE (D × E) × C)—was analyzed. In order to understand the genetic determination of the responsiveness characteristic to fertilizer, a genealogical approach was applied. This approach included the genotype similarity hypothesis: if the hybrid and parental components in its pedigree have the same level of trait manifestation. The estimation of the effectiveness of nitrogen fertilizer was carried out based on such economically valuable traits as yield of green mass and grain yield. It was shown that the increase in the yield of green mass and grain of hybrids and selfpollinated maize lines from fertilizer mainly dependent on weather conditions during vegetation. However, differences between hybrids and their original forms on responsiveness to nitrogen were detected. The highest increase in the yield of green mass and grain provided by nitrogen fertilizer was detected for the three-way cross maize hybrid Mashuk 355 MV and its parental forms. On average in 2012–2015, the green mass increase for the hybrid Mashuk 355 MV accounted for 13%, its parental form (DE) was 16%, and parental forms of hybrid DE (D and E) were 18 and 14%, respectively. The green mass increase for the hybrid Mashuk 350 MV accounted for 10%, the parental form (AB) was 12%, and its basic lines were A 11% and B 12%. The grain yield increase from the nitrogen for original forms of three-way cross Mashuk 355 MV (DE, D, E) was 10%, which was significantly higher than the increases in parental forms of the hybrid Mashuk 350 MV (AB (3%), A (0.3%), B (3%). The study of the reaction of mid-ripening maize hybrids to nitrogen fertilizer revealed that the efficient use of nitrogen by a hybrid depends on the responsiveness of its parental components.