Apical dominance and growth of various sudangrasses and sudangrass hybrids

Abstract

Six varieties, Sudax 11, X-1750 (sorghum x sudangrass), Trudan I (sudangrass x sudangrass), Greenleaf (sudangrass pollinator for both Sudax 11 and X-1750), Atlas B and 31-12 B (seed parents for Sudax 11 and X-1750, respectively) were harvested at three stages of growth: 90-120 cm tall, early boot (50% of plants with flag leaves) and early bloom (50% of plants at anthesis). Plants in each frequency were clipped to leave 15 cm and 45 cm stubble. Sudax 11 plants were treated with NAA (200 ppm), GA₃ (200 ppm), 2,4-dichloroanisole (200 ppm), kinetin (200 ppm) and benzyladenine (2000 ppm), all of which are plant growth regulators. Regulator applications were made at six stages or conditions of plant development: plants 15 cm tall, plants 90-120 cm tall, plants clipped to 15 cm when 90-120 cm tall, plants clipped to 45 cm when 909-120 cm tall, plants with flag leaves and plants initiating anthesis. In addition, Sudax 11, X-1750, Atlas B and 31-12 B stem sections, 2 cm in length, from the third above ground internode and the peduncle were measured for auxin uptake and transport at weekly intervals using auxin-¹⁴C. ...