Photosynthetic potential of early maturing maize hybrids under the conditions of the Central Black Earth region

The aim of the study was to evaluate new hybrids of early maturing maize of different ecological and geographical origin, suitable for cultivation for grain in dark grey forest soils of the Central Black Earth zone, by photosynthetic indices. Due to the recent trends in agriculture to increase the sown areas of maize, as well as the appearance of a large number of hybrids on the market for agricultural organisations, three early maturing hybrids from different originators were selected: Ross-140 SV (FGBNU ‘National Grain Centre named after P.P. Lukyanenko', Russia), Dolphin (Euralis Semences, France), Talisman (Syngenta, Switzerland). The maximum value of leaf area was recorded in the phase of panicle emergence, further the value goes down. For hybrid Ross-140 CB, FAO 140 leaf area in the initial period of vegetation increased from 16.5 thousand*m2/ ha in the phase of 5-7th leaf to 45.9 thousand*m2/ ha in the phase of panicle emergence, i.e. 2.8 times. For hybrid Dolphin, FAO 180 this indicator increased 2.9 times. And for hybrid Talisman, FAO 190, the leaf surface area increased 2.6 times by the phase of panicle emergence. In the phase of milk-wax ripeness in hybrid Ross-140 SV, FAO 140, there was a reduction in leaf area by 4.9 thousand*m2/ha relative to the phase of panicle emergence. For hybrid Dolphin, FAO 180 - by 6.6 thousand*m2/ha, and for hybrid Talisman, FAO 190 - 3.6 thousand*m2/ha. The results indicate that the first two hybrids have a more noticeable decrease in photosynthesis intensity by the stage of milk-wax ripeness compared to the hybrid Talisman, FAO 190, which retained a significant part of leaf surface. The total photosynthetic potential of maize hybrid crops averaged 2.41 million*m2/ha days in hybrid Ross-140 CB, 2.64 million*m2/ha days in hybrid Dolphin and 2.73 million*m2/ha days in hybrid Talisman.