Raspberry biotisation for quality plant production
Résumé
Biotisation with beneficial mycorrhizal fungi and bacteria has been shown to be efficient in improving raspberry plant growth, particularly during the acclimatisation phase of in vitro produced plants. It also increases raspberry tolerance to Phytophthora fragariae var rubi which causes disastrous effects in the field and is not efficiently controlled by fungicides. The contamination of young plants during their multiplication has been a major source of spreading for this disease. For quality insurance, it is therefore important to produce plants which are healthy and devoid of P. fragariae var rubi contamination. In addition, the raspberry market is growing following the discovery of antioxidant molecules (AOM) which have protective effects against cancer, cardiovascular and neuro-degenerative diseases as well as diabetes. However, AOM production in raspberry depends on several factors, including varieties and culture conditions. Our aim is therefore to optimise biotisation of raspberry in order to gain a long-term positive effect on plant quality in terms of growth, health and AOM content. For this purpose, several parameters have to be taken into consideration, including inoculum quality, appropriate growth substrate, fertilisation regime and plant variety. Different inocula and growth substrates were compared to improve efficiency of raspberry biotisation. In order to assess plant sanitary status during plant production and in the field, a nested PCR protocol was developed for the simultaneous detection of AM fungi and P. fragariae var rubi in inocula, growth substrates and plant tissues.