Effects of synthetic hormone substitutes and genotypes on rooting and mini tuber production of vines cuttings obtained from white yam (Dioscorea rotundata, Poir)

Abstract

This study was designed to evaluate the effects of some root - promoting substances on rooting and mini tuber formation using vine cuttings obtained from two genotypes (TDr 335 and TDr 93 - 49) of white yam (D. rotundata). The ashes were obtained from rice straw, bamboo, Gliricidia sepium, dry leaves of Azardiracta indica (neem), and 1% indolebutyric acid (IBA). These were powdered on the nodal wounds of vine cuttings before they were planted in planting media (carbonized rice husk). The plant ashes were mixed at 1, 3 and 5 g each in 100 ml of water. Coconut water was also diluted at 1, 5 and 10 ml in 100 ml of water while pyroligneous acid (PA) was diluted (1 ml each in 500, 1000, 2000 and 3000 ml in
5000 ml of water). Both dilutions were used to treat vine cuttings before planting in cups filled with carbonized rice husk. The vine cuttings were sampled for rooting percentage, number of roots, root length and mini tuber initiation 21 days after treatment (DAT). The number and weight of tubers obtained from IBA and wood ash treated vines were not significantly different. The rice straw ash, IBA and neem leaves powder treated vines produced greater rooting percentage (above 70%) than percent rooting obtained from vines treated with other plant ashes. Rice straw ash (5% concentration) had the highest rooting percentage (80%) relative to other plants ash concentrations. Higher rooting percentage was obtained in coconut water diluted at 1 and 5% than 10 and 100% dilutions. Rooting percentages from vine cuttings treated with pyroligneous acid (PA) dilutions were not better than control (unteeated). The rooting percentages  obtained from vines treated with different concentrations of plants ashes, root - promoting substances and control in this study were not significantly different (P = 0.05), except in vine cuttings treated with 5 g rice straw ash in 100 ml of water. Higher values of rooting percentage, number of roots, root length and mini tubers were obtained from genotype TDr 93 - 49
compared with values recorded from vine cuttings obtained from the genotype TDr 335.