Bio-Chemical Factors Associated with Resistance to Aphid, Hyadaphis coriandari (Das) in Fennel at Bikaner, Rajasthan, India

Fennel (Foeniculum vulgare Miller) is a significant spice crop from the Apiaceae family, often referred to as 'saunf,'. Aphid, Hyadaphis coriandari (Das) remained chief constraints in realising potential production and productivity of fennel in arid region. The biochemical characters viz., free amino acids, total soluble sugar and phenol content in different genotypes of fennel were responsible for resistance. The experiment was conducted using a randomized block design and involved ten different fennel varieties with three replications. The plot size was 2.4 x 3.0 meter and inter row and inter plant distance were 40 cm x 20 cm, respectively. The biochemical characters of varieties/entries viz., total soluble sugar, total phenols and free amino acids were estimated during peak aphid population on the crop. The free amino acids content in different varieties varied from 1.05 to 2.93 per cent. The variety RF-205 contained lowest per cent of free amino acid, harbored minimum aphid population and the RF-145 contained highest per cent of free amino acids and had highest aphid population. The RF-205 variety lowest content of TSS (0.90 mg/100g) harbored lowest aphid population (44.40 aphids/plant) and variety AF-2 contained highest 1.14 mg/100g of TSS. That shows least susceptibility against this pest. The total phenol content ranged from 2.33 to 4.55 per cent being minimum in RF-145 and maximum in variety RF-205. Total phenol (r= -0.99) were significantly negatively correlated with peak aphid population.