S19 - Session O6 - Influence of plant age, chilling hours and genotype in the number of new shoots in red raspberry root system

Authors: Pedro N. Brás Oliveira *, João Viegas Oliveira, Cristina Moniz Oliveira, Francisco Luz

Little is known about the factors that influence vegetative multiplication of raspberry plants by root buds in order to maximize plant production in the nurseries. The number of buds in the roots capable of producing suckers are cultural (planting date, cane density, soil type, moisture, etc.) and climate (temperature and photoperiod) dependent. Plant age is a factor that influence the weight of the root system, due to a longer time for root development and chilling is an important factor in breaking raspberry bud dormancy. Two trials were setup. In the first trial the interaction between root age (corresponding to three planting dates n 16 March, 06 April and 27 April) and the time in the cold chamber (without chilling, 15 days, 30 days and 45 days at 5 ˚C) was evaluated. In a second trial, it was analyzed the importance of genotype in root bud formation. Four genotypes of 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 influence on the number of suckers obtained with the treatment of 30 days being the most effective. In the second trial it was observed an independence of the genotypes in relation to the origin, that is, in the same origin there were genotypes with differences of about 30 suckers.