Foliar application of zinc sulphate alone and in combination with Gibberellic Acid (GA3) and Naphthalene Acetic acid (NAA) on the growth, yield and quality of onion

Onion is an important vegetable crop having economic significance. Onion genotypes vary in size, colour and taste. In the current study, three onion genotypes i.e. Shah Alam, Phulkara and Nasr puri were grown in a pot culture to study growth, yield and quality parameters treated with zinc (Zn) and plant growth regulators (PGRs) i.e. gibberellic acid and naphthalene acetic acid. The experiment was carried out for two consecutive years. The results showed that leaf length and number of leaves per plant showed significant differences in their means by application of Zn and PGRs treatments during the initial year of the study and non - significantly in the following year. The yield parameters including bulb diameter and bulb weight pot-1 were significantly affected by the fortification of Zn and PGRs. The highest bulb diameter of 7.08 cm was recorded in the Nasr puri genotype which was fortified with 0.5 % Zn and NAA. While Shah Alam and Phulkara genotypes exhibited smaller bulb diameters. The bulb weight per pot showed significantly higher values for both the experimental years with the highest weight of 0.20 and 0.57 kg recorded in the Nasr puri fertilized with zinc sulphate. The qualitative parameters have shown significant variation in treatments fortified with Zn and PGRs. Total sugar and total soluble solids have changed significantly amongst treatments, while pyruvic acid was not significantly changed amongst the genotype by Zn and PGRs treatments. It is concluded that both Zn and PGRs have shown significant effects on onion genotypes in terms of quantitative and qualitative aspects.