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Measurement of grape root firmness and its application to the evaluation of cold hardiness

Author:
Gao, Z., Zhai, H., Du, Y.‐P.
Source:
Australian journal of grape and wine research 2018 v.24 no.4 pp. 406-412
ISSN:
1322-7130
Subject:
cold tolerance, cultivars, cutting, firmness, grapes, phloem, texture, xylem
Abstract:
BACKGROUND AND AIMS: In this study, the cutting force and work to cut 12 grape cultivars with different cold hardiness were measured with a texture analyser to examine root firmness and its application to the evaluation of cold hardiness. METHODS AND RESULTS: The transverse cut method involved cutting in a direction perpendicular to vascular orientation, and the longitudinal cut method involved cutting in a direction perpendicular to the transverse cut. The transverse maximum cutting force (MCF) and cutting depth showed a linear relationship, while work of transverse cutting and cutting depth indicated a power function. Dornfelder, Merlot Noir, Tannat, Carmenère and Syrah required the least MCF, Vidal, SO4, 3309C and 101‐14M a moderate MCF, and Chambourcin, Beta and Frontenac the highest MCF. Work classification of the 12 cultivars was consistent with MCF classification. CONCLUSIONS: The correlation coefficients of cold hardiness and MCF at 2 mm cutting depth was the highest in the transverse cut, and the correlation coefficients of cold hardiness and phloem MCF of 1 mm cutting depth was highest in the longitudinal cut. The root phloem/radius ratio was correlated negatively with MCF and work, yet the correlation between xylem/radius and MCF and work was positive. The exodermis/radius ratio was significantly correlated with the MCF and the work of a transverse section and phloem longitudinal section. SIGNIFICANCE OF THE STUDY: The cross‐sectional cut of 2 mm depth and longitudinal cut of 1 mm depth could distinguish the firmness of different cultivars, and could be considered as the determinant index of cold hardiness.
Agid:
6117388