Multidisciplinary characterization of primocane raspberries compared to floricane fruiting cultivars

Fruit quality was investigated on primocane fruiting and biennial fruiting raspberry cultivars through several approaches: horticultural evaluations, volatile analysis by SPME GC-MS and PTR-MS, and molecular studies were used in order to characterize these top varieties. Primocane (PC: ‘Autumn Bliss’, ‘Heritage’, ‘Polka’, ‘Josephine’, ‘Caroline’, ‘Himbotop’, ‘Pokusa’, ‘Opal’, ‘Benefis’) and floricane (FC: ‘Tulameen’, ‘Glen Ample’, ‘Laszka’) fruiting varieties were compared and analysed for three growing seasons in soil-less conditions and screened for phenotypical characteristics of the plants and fruits. The parameters investigated were related to morphological, phenological, and horticultural aspects, to shelf life and tolerance to the main diseases of this crop. Two-spotted spider mite (Tetranychus urticae Koch) infestation was recorded on the new and the fruiting canes of the raspberry accessions and Resseliella theobaldi (Raspberry Cane Midge – RCM) tolerance was also investigated for two years. Attacks of aphids were also screened. The volatiles emitted by raspberry genotypes have been evaluated by means of Solid Phase Micro Extraction (SPME) combined with Gas Chromatography-Mass Spectrometry (SPME GC-MS) and by Proton Transfer Reaction-Mass Spectrometry (PTR-MS). While GC analysis allows the identification of the main compounds of the volatile profiles of the raspberries, PTR-MS spectra can serve as sample fingerprints for the varieties characterization. Among the different compounds identified, terpenes seem to separate samples in two main classes allowing a first important cultivar screening. The study has also progressed on the genetic identification of the Rubus genotypes comparing the chemical evaluation with analysis based on molecular markers. Amplifiable DNA was recoverable from Rubus leaves and a set of Single Nucleotide Polymorphisms (SNP) markers on enzyme sequences involved in the specific biochemical pathways started to be developed.