The maximum value of the indicator of the photosynthetic potential was fixed at sowing in the third decade of April, 12-13 flowering leaves in the interphase period-1189-1686 thousand m 2 /ha. The ripeness group of the hybrid influenced the formation of the photosynthetic potential. The highest values of the indicator were established during all the sowing periods of the midseason of the Kahovski Hoghbroide, which were in the period of 12-13 leaves-flowering of the rockers in the range of 1375-1686 thousand m 2 /ha.