Breeding progress achieved of Bulgarian maize hybridsfrom different vegetation groups I. Grain yield

摘要

For fifteen years period (2001-2015) different number of MRI - Knezha hybrids were tested in ecological trials including 3 to 6 locations and 4 FAO groups. Aggregated results for the grain yield describe a substantial tendency of achieved breeding progress for that trade independently from different number of hybrids tested every year and fluctuation of agrometeorological environments for the period. Grain yields by FAO groups are distributed (as general means) as follows: FAO 300 - 400 - 7190 kg/ha~(-1); FAO 400 - 500 - 7330 kg/ha~(-1); FAO 500 - 600 -7165 kg/ha~(-1) and FAO 600+ - 7057 kg/ha~(-1). The middle-early group (FAO 400 - 500) has a relatively highest grain yield, but the late group (ФАО 600+) has the biggest variation. General adaptation index (X_1- b_1) values point out the best position of middle-early hybrids (FAO 400 - 500) again.By maturity groups average annual increase is 97 kg/ha~(-1) for early hybrids (FAO 300 - 400) which is the highest followed by middle-early ones (FAO 400 - 500) - 67kg/ha~(-1). At middle-late group (FAO 500-600) that increase is the least - 13 kg/ha~(-1), but at full season one (FAO 600+) it is 32 kg/ha~(-1), mean per year for the period. For all FAO groups the increasing is 52.3 kg/ha~(-1), average rate for 15 years period, which could be indicated like achieved breeding progress.The relation between grain yield and vegetation period (by FAO groups) is not linear which confirms previous investigations and proves the ability for high productivity maize hybrids breeding with earlier maturity.