Studies on effect of growth regulators and herbicides on gladiolus

A field experiment was carried out to evalutate the effects of growth regulators (control, preplanting dip of corms in 100 ppm GA₃ solution for 24 hrs, pre-plantind dip of corms in 500 ppm thiourea solution for 24 hrs) and nine weed control treatments on gladiolus cv. ‘unerican Beauty’. The nine weed control treatments were weed free; weedy check; atrazine 3 kg ha⁻¹ at 1–2 days after planting (DAP) followed by (fb) one hand hoeing (HH) at 120 DAP; atrazine 1.5 kg ha⁻¹ at 1–2 DAP fb one HH + atrazine @ 1.5 kg ha⁻¹ at 120 DAP; atrazine @ 0.75 kg ha⁻¹ at 1–2 DAP fb one HH + atrazine 0.75 kg ha⁻¹ at 120 DAP; trifluralin 2 kg ha⁻¹ at 1–2 days before planting (DBP) fb one HH at 120 DAP; trifluralin 1.0 kg ha⁻¹ at 1–2 DBP fb one HH + trifluralin 1.0 kg ha⁻¹ at 120 DAP; oxyfluorfen 0.50 kg/ha at 1–2 DAP fb one HH + oxyfluorfen 0.25 kg ha^−t at 120 DAP. Pre-planting dip treatment of gladiolus corms with GA₃ (100 ppm) and thiourea (500ppm) markedly improved the quality and production of spikes as well as corms. More uniform sprouting, better flowering, better coemel production, more suppression of weeds and higher additional return were additional benefits of GA₃ over thiourea. Among herbicidal treatments, atrazine @ 3kg ha⁻¹ (either in single dose or in two equal splits) was observed comparatively more efficient in controlling weeds; but caused phytotoxicity to cropplants. Among the rest of the herbicidal applications, most consisitant acceptable in dry weight accumulation in weeds and their intensity was provided by oxyfluorfen 0.25 kg + 0.25 kg ha⁻¹ closely followed by oxyfluorfen 0.50 kg ha⁻¹ and trifluralin 2.0 kg ha⁻¹.