Influence of Seed Size and Growth Stage on Forage Sorghum‐sudangrass Hybrid cv. P988 Grown on Striga‐infested Soil

Abstract

AbstractDelaying harvest of P988 from the boot stage to the maturity stage significantly reduced 1) forage greenchop yield of P988 grown on Striga‐ infested soil at 1st and 3rd harvest of July sowing and at 3rd harvest of October sowing, 2) root dry weight of P988 grown on Striga‐infested soil at 3rd harvest of July and October sowing, and 3) forage sucrose of P988 grown on Striga‐infested soil at 3rd harvest of July sowing and at 1st and 3rd harvest of October sowing. Reductions in forage greenchop yield of P988 with successive harvests were accelerated by Striga infestations. The root dry weight was significantly greater from P988 plants grown from small compared to large seed. Delaying harvest of P988 to the maturity stage was associated with significant increases in number of open Striga flowers at 1st and 2nd harvest from October planting and in Striga shoot dry weight at 1st harvest of July and 1st and 2nd harvest of October planting. These increases were positively correlated with forage sucrose of P988. Results suggest that optimal forage greenchop yield on Striga‐infested soil may be obtained from P988 plants grown from small seed and harvested at the boot stage.