Culturing of root-knot nematode, Meloidogyne incognita in excised roots and callus cultures of tomato

Studies were undertaken to find out the in vitro response of various explants viz., seed, leafdisc, excised roots of tomato cv. Co3 on Murashige and Skoog medium with growth regulators for callus induction and rhizogenesis respectively. The root-knot nematode, Meloidogyne incognita was inoculated on tomato leaf, root call and on root culture to study their multiplication rate under in vitro conditions. The explant leaf disc showed a profuse growth of callus on MS media supplemented with 0.5 mg 1⁻¹ 2, 4-D and 3.0 mg 1⁻¹ BAP. Tomato seed germinated on MS media containing 1.0 mg 1⁻¹ NAA and 0.5 mg 1.1 BAP registered high frequency of rooting and more number of roots. Optimal root callus induction was found to be on the MS media at 1.0 mg 1⁻¹ NAA and 1.5 mg 1⁻¹ BAP. Tomato leaf calli of 32 days old did not seem to favour Meloidogyne incogita multiplication. Inspite of permitting feeding of M. incognita the tomato root calk did not support its development or multiplication, as only 45.33 percent larvae penetrated the callus and 27.94 per cent reached the adult female stage. But, in in vitro root culture, increased nematode reproduction was observed as out of the 66.0 per cent of the larvae penetrated, 75.76 per cent reached the adult female stage.