Effect of genotype,growth regulators,carbon source,and pH on shoot induction and plant regeneration in tomoto

Summary Ten cultivars of tomato were screened for their ability to produce shoots and shoot primordia on media containing a range of 6-benzyladenine (BA) concentrations (0.0–4.0 mgl⁻¹; 0.0–17.7 μM) in combination with indole-3-acetic acid (IAA; 0.0, 0.1, 0.2 mgl⁻¹; 0.0, 0.57, 1.14 μM, respectively). Both genotypes and growth regulator levels showed significant differences at α=0.05. However, their interaction was not significantly different. A comparison of the mean number of shoots produced six cultivar classes, with UC82, UC97-3, Castlerock, Red Rock, and Peto86 producing the highest means. There were four cultiver frequency classes, the highest including cultivars Peto Rock (93.7%), Peto86 (92.3%), and Strain B (90.7%). Growth regulator mean comparisons produced eight classes, the highest included three different BA/IAA combinations, with media containing 2.0 mgl⁻¹ (8.87 μM) BA and 0.2 mgl⁻¹ (1.14. μM) IAA giving the highest mean and frequency (94.1%). The effect of carbon source was studied using glucose, fructose, maltose, and sucrose at 3.0% concentration. Three high regenerating genotypes and four media were used in combination with each sugar. Sugars were significantly different with maltose giving the highest number of shoots (31.6) followed by glucose (20.9). Growth regulator means, sugar-growth regulator interaction, and cultivar-sugar interaction were significant. A three-way interaction was nonsignificant. The effect of maltose and sucrose concentration (1.5–9.0%) showed the positive effect of maltose over sucrose in inducing shoots and in reducing loss rates of shoots on the regeneration media. Maltose at 1.5, 3.0, and 4.5% was the most effective. Six pH values (4.0–6.5) were used to test their effect on shoot induction in three cultivars (Peto86, UC97-3 and Castlerock). pH effects and cultivar-pH interaction were not significant.