TY - JOUR

T1 - Neck shrivel in European plum is caused by cuticular microcracks, resulting from rapid lateral expansion of the neck late in development

AU - Khanal, Bishnu P.

AU - Bhattarai, Anil

AU - Aryal, Divya

AU - Knoche, Moritz

N1 - Funding Information: We thank Stefan Eschke, Anne Grund. Erik Schulte and Andreas Zschammer, Federal Fruit Variety Office, Wurzen, and Michael Neumüller, Bayrisches Obstzentrum, for samples of the various cultivars of plum fruit and Alexander Lang for language editing and helpful comments on an earlier version of this manuscript. Funding Information: Open Access funding enabled and organized by Projekt DEAL. This research was funded by grant KN 402/20-1 from the Deutsche Forschungsgemeinschaft (DFG).

PY - 2023/9

Y1 - 2023/9

N2 - Main conclusion: Susceptibility to neck shrivel in European plum is due to cuticular microcracking resulting from high surface area growth rates in the neck region, late in development. Abstract: Susceptibility to the commercially important fruit disorder ‘neck shrivel’ differs among European plum cultivars. Radial cuticular microcracking occurs in the neck regions of susceptible cultivars, but not in non-susceptible ones, so would seem to be causal. However, the reason for the microcracking is unknown. The objective was to identify potential relationships between fruit growth pattern and microcracking incidence in the neck (proximal) and stylar (distal) ends of selected shrivel-susceptible and non-susceptible cultivars. Growth analysis revealed two allometric categories: The first category, the ‘narrow-neck’ cultivars, showed hypoallometric growth in the neck region (i.e., slower growth than in the region of maximum diameter) during early development (stages I + II). Later (during stage III) the neck region was ‘filled out’ by hyperallometric growth (i.e., faster than in the region of maximum diameter). The second category, the ‘broad-neck’ cultivars, had more symmetrical, allometric growth (all regions grew equally fast) throughout development. The narrow-neck cultivars exhibited extensive radial cuticular microcracking in the neck region, but little microcracking in the stylar region. In contrast, the broad-neck cultivars exhibited little microcracking overall, with no difference between the neck and stylar regions. Across all cultivars, a positive relationship was obtained for the level of microcracking in the neck region and the difference in allometric growth ratios between stage III and stages I + II. There were no similar relationships for the stylar region. The results demonstrate that accelerated stage III neck growth in the narrow-neck plum cultivars is associated with more microcracking and thus with more shrivel.

AB - Main conclusion: Susceptibility to neck shrivel in European plum is due to cuticular microcracking resulting from high surface area growth rates in the neck region, late in development. Abstract: Susceptibility to the commercially important fruit disorder ‘neck shrivel’ differs among European plum cultivars. Radial cuticular microcracking occurs in the neck regions of susceptible cultivars, but not in non-susceptible ones, so would seem to be causal. However, the reason for the microcracking is unknown. The objective was to identify potential relationships between fruit growth pattern and microcracking incidence in the neck (proximal) and stylar (distal) ends of selected shrivel-susceptible and non-susceptible cultivars. Growth analysis revealed two allometric categories: The first category, the ‘narrow-neck’ cultivars, showed hypoallometric growth in the neck region (i.e., slower growth than in the region of maximum diameter) during early development (stages I + II). Later (during stage III) the neck region was ‘filled out’ by hyperallometric growth (i.e., faster than in the region of maximum diameter). The second category, the ‘broad-neck’ cultivars, had more symmetrical, allometric growth (all regions grew equally fast) throughout development. The narrow-neck cultivars exhibited extensive radial cuticular microcracking in the neck region, but little microcracking in the stylar region. In contrast, the broad-neck cultivars exhibited little microcracking overall, with no difference between the neck and stylar regions. Across all cultivars, a positive relationship was obtained for the level of microcracking in the neck region and the difference in allometric growth ratios between stage III and stages I + II. There were no similar relationships for the stylar region. The results demonstrate that accelerated stage III neck growth in the narrow-neck plum cultivars is associated with more microcracking and thus with more shrivel.

KW - Allometric growth

KW - Allometry

KW - Cuticle

KW - Fracture

KW - Prunus domestica

KW - Transpiration

UR - http://www.scopus.com/inward/record.url?scp=85166597739&partnerID=8YFLogxK

U2 - 10.1007/s00425-023-04218-9

DO - 10.1007/s00425-023-04218-9

M3 - Article

C2 - 37542542

AN - SCOPUS:85166597739

VL - 258

JO - PLANTA

JF - PLANTA

SN - 0032-0935

IS - 3

M1 - 62

ER -