S. VULCHINKOV1, D. ILCHOVSKA1, B. PAVLOVSKA2 and K. IVANOVA2
1 Maize Research Institute, BG – 5835 Kneja, Bulgaria
2 State Executive Agency for Variety Testing and Seed Control (IASAS), BG – 1113 Sofia, Bulgaria
VULCHINKOV, S., D. ILCHOVSKA, B. PAVLOVSKA and K. IVANOVA, 2013. Trends in productive abilities of maize hybrids from different FAO groups. Bulg. J. Agric. Sci., 19: 744-749
Ten-year data (2001-2010) from official maize hybrids testing in IASAS and preliminary (ecological) trials of Maize Research Institute (MRI), carried out in different locations are compared. Besides the actions of many occasional factors – diversity of environments and great number of hybrids tested from 5 FAO groups (200-600) every year, common tendency of both groups of trials are observed. Grain yield (t/ha) has a relative maximum in semi-late hybrids (FAO 500-600). Closer to them are earlier groups – FAO 300-400 and 400-500. Correlations between grain yield and vegetation period like FAO groups are not significant and their regressions are not linear. Correlations of grain moisture at harvesting (%) and vegetation period are strongly positive and regressions are linear for both of trials. For the period of investigation, a progress of reduction of that trait was observed. Best combinations of relatively high grain yield and low grain moisture were pointed out for early hybrids (FAO 300-400) by performance index (Pi) values. Relatively good combinations of grain yield and stability were observed for FAO 500-600 hybrids, represented by their general adaptation index (xi - bi). IASAS trials, like final step of maize hybrids testing including Bulgarian and foreign varieties with the same checks out yielded MRI trials as average levels by FAO groups, but overcoming the correlation high yield – late maturity, better pi values for earlier genotypes and their adaptation are very similar in both trials groups like general tendency. These results confirm the “post green revolution” trends in maize breeding discussed by Duvick and Gassman (1999).