ROOT FORMATION IN TRUE POTATO SEED PARENTAL LINES BY IBA APPLICATION

An experiment was conducted to study the response of dipping time and various concentrations of IBA (indole-3butyric acid) on days to root initiation, number of roots per stem cutting and root length of stem cuttings of four TPS (true potato seed) parental lines, Atzimba, LT-8, MF-I and TPS-67. Root formation was significantly earlier in the cuttings treated with 150 ppm IBA than cuttings treated with a (control), 100 and 200 ppm IBA at seven days after planting. Similarly, Root initiation was significantly delayed in the cuttings that were treated with a ppm (control) IBA than in the cuttings treated with 100, 150 and 200 ppm IBA at 10 and 14 days after planting. Main effect of TPS parental lines and dipping time was significant on root initiation at 10, 14, and 17 days after planting. Cuttings dipped for 5, 10, 15 seconds in IBA solution initiated roots earlier than the cuttings of control. Main effect as well effect of parental line x IBA concentration interaction was significant on both number of roots per stem cutting and on root length. Under the most favourable combination (Atzimba x 150 ppm) number of roots per stem cuttings reached to 7.5. 150 ppm IBA concentration gave comparatively better results for root length (5.94 cm) and number of roots per stem cutting (5.47). LT-8 produced maximum roots (4.60) per stem cutting while the longest roots (4.71 cm) were noticed in cuttings of Atzimba.