Maturation, topophysis and other factors in relation to rooting in Larix

We examined effects of mist quantity, topophysis (origin of cutting in the crown of 6-year-old trees), maturation state of the donor stock, and time o f sticking on rooting and root system quality of cuttings representing five full-sib hybrid larch families obtained with Larix decidua Mill., L. laric ina (du Roil K. Koch, and L. kaempferi (Lamb.) Sarg. (Sieb. and Zucc.) Gord ., as parents. Mist frequency, supplemental watering and family all had hig hly significant effects on percentage of cuttings rooting and root system q uality. The high-frequency misting regime yielded both higher rooting perce ntages and higher quality root systems than the low-frequency regime withou t supplemental watering. Supplemental watering of the rooting medium in the low-frequency misting regime increased both percent rooting and root syste m quality to values comparable with those obtained by cuttings in the high- frequency misting regime. Rooting of cuttings from the top, middle and bott om whorls of 5-year-old plantation grown trees tended to decline with incre asing height for three of the five families. Overall, height of cutting ori gin did not significantly affect rooting, but when analyzed separately, two families exhibited a significant decline in rooting toward the top of the trees. Age of donor ortet (ranging from 1 to 7 years) significantly affecte d both percent rooting and root system quality. Rooting percentages decline d linearly with age, and root system quality declined more sharply than per cent rooting. The relatively poor root system quality of cuttings from orte ts older than 1 year was closely associated with plagiotropic growth. Softw ood cuttings (stuck in mid-July) rooted better than hardwood cuttings (stuc k in early September) across all families.