being age (3, 6, and 12 week old seedlings) and auxin concentration/wounding (0 IBA/wounded, 0 IBA not wounded, 5,000 ppm IBA wounded, and 10,000 ppm IBA wounded). The treatment structure in 2003 was a 3 x 3 factorial, with the two factors being age (3, 12, and 24 week old seedlings) and auxin concentration (0 IBA, 10,000 ppm IBA, and 20,000 ppm IBA; all wounded).
Statistical Analysis. Data for number of roots per stem, average root length, and rooting percentage were subjected to an analysis of variance (ANOVA) or general linear model of analysis of variance (GLM-ANOVA) using the statistical software CoStat (CoHort software, Monterey, Calif.). Statistical significance of differences between mean values was determined using an LSD separation with a level of significance of P<0.05.
2002 Experiment. Although it was expected that multiple buds would break along the stem and form shoots, pawpaw seedlings displayed strong apical dominance and only what was the uppermost bud after tipping broke and formed a shoot. All other buds remained dormant. Upon analysis, data failed normality testing using Bartlett's Test, therefore these results are not reported. Two-way tables of all treatment means are reported.
Age appeared to affect rooting percentage of seedlings, with twice and three times as many shoots of three-week-old seedlings rooting than shoots of 6-week and 12-week old seedlings, respectively (Table 2.1). Rooted shoots of 6-week-old seedlings produced the most roots per stem, at 2.5, and also had the longest average root length.
IBA concentration also had an impact on rooting percentage, with only 2-3% of control shoots producing roots, compared to approximately 16% of those shoots treated with either level of IBA producing roots (Table 2.2). There did not appear to be differences in rooting percentages between the wounded and unwounded controls, nor between the two levels of IBA. Shoots treated with 5,000 and 10,000 ppm IBA respectively produced 30% and 80% more roots per stem than the control plants. Shoots treated with IBA also produced roots that were approximately 3 times longer than the control shoots.
A breakdown of rooting characteristics by age and IBA concentration can be found in Table 2.3. Only the youngest, 3-week-old shoots were capable of rooting if not