Effect of plant age and auxin treatment on rooting response in stem cuttings of Prosopis cineraria

Rooting behaviour in stem cuttings of Prosopis cineraria was studied. Among 20 treatments, two combinations of auxins: (1) indole acetic acid + indole butryic acid + 2,4-dichlorophenoxy acetic acid, and (2) naphthalene acetic acid + indole butyric acid + thiamine, in concentrations of 2000 and 4000 mg l-1, respectively, stimulated statistically significant (p < 0•05) rooting up to 60% in stem cuttings taken from 6-month-old plants, while the same combinations of auxins with concentrations of 1000 and 4000 mg l-1, respectively, induced rooting up to a maximum of 35% in cuttings from 8-year-old trees. Other treatments with auxins applied singly (IAA, 2000 and 8000 mg l-1; IBA, 2000 and 4000 mg l-1; NAA, 1000 and 8000 mg l-1) or in combinations (IAA + IBA + 2,4-D, 1000 mg l-1; NAA + IBA + thiamine, 1000 mg l-1) induced rooting in 10-50% of cuttings from 6-month-old plants; none of these treatments induced rooting in cuttings from 8-year-old trees