Grapevine root and shoot growth responses to photoselective nets: preliminary results

Photoselective netting is a tool increasingly used in many fruit crops. Most of the research on grapevines has been performed on table grapes. Little is known on how photoselective nets can affect grapevine root system development. This study was therefore conducted to improve understanding of the possible effects of the use of photoselective nets on 'Pinot Noir' (Vitis vinifera L.) root and shoot growth. PAR radiation incidence was significantly reduced by pearl and red nets. However, there were no differences in air temperature and relative humidity among red net, pearl net, and control. Small differences were found in soil water content between net conditions and control. Shoot growth and total leaf area were enhanced under pearl and red net conditions in comparison with control. Leaves under the nets presented similar chlorophyll index values with respect to leaves under control, but after 42 days of exposure to net conditions, the leaf chlorophyll index was lower than that of the control vines. No differences were found in stomatal density in leaves under nets in comparison with the control. Pearl net increased stomatal size in comparison with control. Vines under the nets showed higher root fresh weight. Similarly, root dry matter was increased by the use of nets. Vines growing under pearl net had the highest root dry weight, followed by vines under red net (increase of 84 and 45%, respectively, compared to the control). More study at the physiological and genetic level is needed to improve understanding of the effect of light on vine root development. This will help in the assessment of the potential use of photoselective nets in vineyards to combat excessive solar radiation in the context of climate change.