Microvine: An ecophysiological model for grapevine

Abstract

Microvine is a natural mutant of grapevine characterized by a dwarf, rapid cycling and continuous flowering phenotype. Thanks to both its compacted architecture and to the continuous flowering, new insights into grapevine yield and quality responses to climate changes are expected from this material. However, little is known regarding the main patterns of microvine growth and development, and how they differ or not from grapevines. The present study was thus aimed at quantifying key vegetative and reproductive characters of a reference microvine line (L1) together with the cv. Grenache N., and at comparing the spatial and temporal growth patterns in L1.

Potted plants of L1 and Grenache N. were grown respectively in greenhouse (2011, 2012) and outside (2009). Organs sizes were measured twice a week. Berry fresh weight and total soluble solids were determined at harvest. Shorter internodes and smaller leaf area were observed in L1 compared with Grenache N. Along the axis, L1 continuously held inflorescences instead of tendrils. Flowers and berries number per inflorescence were lower in L1 than in Grenache N., and flower or berry abortion was nearly zero in L1. In spite of these differences, phyllochrons and leaf expansion duration after leaf emergence were similar for both materials. Moreover, maximal berry diameter and fresh weight were close for the two genotypes. A phenological model simulating leaf and berry key developmental phases was parameterized for L1. The model was used to convert spatial leaf and berry growth dynamics along the axis into temporal dynamics, which were compared to temporal dynamics at a given phytomer rank. The good match between the two patterns indicated the temporal changes can be inferred from spatial patterns.

These results open new fields in grapevine studies. Short term experiment can now be designed under fully controlled environments using microvine in order to quantify the impact of abiotic stresses on a variety of traits underlying yield or berry quality simultaneously.