MANAGEMENT SYSTEMS TO PRODUCE TWO OR THREE FRUIT HARVESTS IN RED RASPBERRY UNDER TEMPERATE CLIMATE

Abstract

In temperate regions, the primocane-fruiting (autumn fruiting) red raspberry (Rubus idaeus L.) can be field grown under two managements systems to obtain either one or two annual fruit harvests. In this study these management systems were modified by adding one pruning and application of plant growth regulators, in order to obtain an additional fruit harvest in ‘Malling Autumn Bliss’, a primocane- fruiting red raspberry cultivar, grown under greenhouse conditions in a temperate climate at 2240 masl. In January 2003, the two modified managements systems were established in one-year old plants growing on a substrate composed by soil and red sand (3:1, v/v) under a polyethylene greenhouse without heating. These two systems are called ‘three crops system’ (SMTC) and ‘two crops system’ (SMDC). The evaluation was performed in 2003 and 2004, based on the fruit maturity kinetics, number of harvests, yield and fruit quality. In 2004, a year without early frost, we obtained three harvest periods (Spring, Summer and Fall) under SMTC, and two crops (Summer and Fall) under SMDC. That is, we succeeded in obtaining an additional harvest, which occurred in Fall, in both systems. This third harvest yielded 30 to 36 % less than that in Summer, but it was similar in fruit quality and occurred when prices were highest. Taking into account harvest periods, yield per harvest, cumulative yield and quality fruit, the management system for two harvests is better than that for three harvests, since it uses less labor for pruning and harvesting.