Growth assessment of F1 hybrid salix seedlings in Karaj experimental site

Willow (Salixsp.) is one of the main trees occurring within valleys, plains and the river margins in Iran. The aim of study was to evaluate and compare the growth of willow hybrids and parents. Therefore, hybrid seedlings from S. alba (female) x S. alba (male), S. alba x S. excels and S. alba x S. fragilis crosses were planted in the field in April 2012. In first stage, superior hybrids were selected based on growth characteristics. In the second stage hybrid seedlings and parents were tested by planting cuttings (5 cuttings for each hybrid and parents) in the nursery. Growth traits such as survival rate, collar diameter, height, number of branches and stem form were measured at the end of growth season. Measuring growth characteristics of hybrids showed that 7 hybrids from S. alba x S. alba , 7 hybrids form S. alba x S. excelsa and 2 hybrids from S. alba x S. fragilis crosses were associated with straight stem form as well as the highest diameter and height growth. The average diameter and height growth of hybrid seedlings from planted cuttings cuttings showed two hybrid S. alba x S. alba crosses with the highest growth. Moreover, four S. alba x S. excelsa crosses and one seedling from S. alba x S. fragilis hybrid showed the highest height growth compared to the parents. The superior hybrids also showed straight stems. It is concluded that the superior hybrid seedlings from this study can be evaluated in the next phase of compatibility.