Acclimatization and establishment of micropropagated plants of hazelnut Corylus spphybrids

A series of hybrid hazelnuts developed by Phillip Rutter, Badgersett Research Farms, Canton, MN, have gained interest as potential alternative crops for farmers in mid-western USA. These hybrids were derived from crossing the commercially important Corylus avellana with North American species (C. cornuta and C. americana), possess tolerance to the harsh winter temperatures of the region and are relatively disease resistant, but they are difficult to propagate by conventional methods. Successful micropropagation has been achieved in our laboratory for selected genotypes by employing a medium based in part on the composition of the hazelnut kernel (Nas and Read, 2004). Acclimatization and subsequent establishment in the field proved to initially be an obstacle, but direct rooting of the microcuttings in rehydrated compressed peat pellets under conditions of high humidity and moderate light and temperature led to successful production of potted plants of one-half to one meter in height. Use of direct rooting in special plastic containers, together with a regimen of dilute nutrient sprays has facilitated more efficient and rapid multiplication, resulting in improved potential for scaled-up acclimatization and field establishment of the micropropagated hazelnut hybrids. Field plantings have been made in several locations and are being evaluated for trueness to type, winter survival, disease tolerance, growth characteristics and productivity.