Morphological Performance of Onion under Exogenous Treatments of GA3

Abstract

The present study was conducted to assess the morphological response of onion plants to different GA3 levels (0, 20, 40 and 60 ppm). The factor levels of GA3 were applied during transplanting by root soaking and foliar spray at 30 and 60 days after transplanting. The gibberellic acid had a great effect on increasing plant height (46.50 cm), shoot biomass (641.67 g m-2), bulb biomass (1125.00 g m-2) and also dry matter accumulation in onion plants under the effect of 60 ppm compared to control. Plants grown up without GA3 application were shorter than those grown with GA3 spray where the lowest plant height (34.67 cm) was remarked. The leaf number (11.43) was considerably increased when 60 ppm GA3 was used as the growth promoter factor in comparison to control. The plants attain minimum fresh biomass at harvesting time in the shoot (441.67 g m-2) and bulb (641.67 g m-2) grown in control plot. Considerably (41.63%) more dry shoot biomass accumulation was recorded in 60 ppm GA3 treated plants in comparison with the control at harvesting stages. Insignificant effect by all concentration of GA3 was found in bulb length, fresh root biomass and dry root biomass. Thus, the use of 60 ppm GA3 can be recommend for onion production due to the significantly increased of the fresh bulb biomass with about 42.96% over control.

Keywords

• Allium cepa
• bulb crop
• growth regulators
• morpho-physiology