Influence of plant age, chilling hours and genotype on the number of new shoots in red raspberry root systems

Abstract

Little is known about the factors affecting vegetative propagation of raspberry plants by root buds to maximize plant production in the nurseries. The number of buds in the roots that can produce suckers is cultural (planting date, cane density, soil type, moisture, etc.) and climatic (temperature and photoperiod) dependent. Plant age is a factor that influences root system weight as a longer time for root development and chilling is an important factor in breaking raspberry bud dormancy. Two trials were set up. In the first trial the interaction between root age (corresponding to three planting dates – March 16, April 6 and April 27) and the time in the cold room (without chilling, 15 days, 30 days and 45 days at 5°C) was evaluated. In a second trial, the importance of genotype for root bud formation was analysed. Four genotypes from three origins (seeds from three female parents open pollinated) were used. In the first trial there was no interaction between chilling and plant age, but chilling had a significant impact on the number of suckers obtained, with the 30-day treatment being the most effective. In the second trial the genotypes were observed to be independent of origin, that is, in the same origin there were genotypes with differences of about 30 shoots.