Morphological and Chemical Variation of Wild Sweet Chestnut (Castanea sativa Mill.) Populations

Igor Poljak,Nada Vahčić,Zlatko Šatović,Marilena Idžojtić,Zlatko Liber

doi:10.3390/f13010055

Abstract

Sweet chestnut (Castanea sativa Mill., Fagaceae) is one of the oldest cultivated tree species in the Mediterranean, providing multiple benefits, and, since it has edible seeds, it represents an interesting model species for the research of morphological and chemical variability. In this study, morphometric methods and chemical analyses were used to quantify the extent of differences in phenotypic and nutritional traits between eight natural populations of sweet chestnut from different environmental conditions, where different management types are applied, high-forest and coppice. The samples were collected from the Prealps in Italy to the western part of Bosnia and Herzegovina. In total, 31 nut and kernel morphometric and nutritional traits were studied on 160 trees, and various multivariate statistical analyses were used to study intra- and interpopulation variations. Both analyses, morphometric and chemical, revealed a similar pattern of diversity, with morphological and chemical variability not associated with geographic or environmental variables. In addition, we found significant correlations between morphometric and chemical data. High phenotypic variability was determined both among and within the studied populations, and all populations had a similar level of diversity. The results of the analysis of morphological and chemical diversity can have many practical applications for the management, production, and conservation of the sweet chestnut genetic resources for nut production.

Highlights

Sweet chestnut (Castanea sativa Mill.) is a medium–large, monoecious insect- and wind-pollinated deciduous tree that belongs to the family Fagaceae [1]
Pollen and plant macrofossil analyses suggest that the most probable natural range of sweet chestnut is delimited by several macro-regions [5]: the Transcaucasian region, northwestern Anatolia, the Apennines on the Italian Peninsula, the hills of the Prealps in northeastern Italy with a possible extension into Slovenia, the Cantabrian coast in the Iberian Peninsula, and the Balkan Peninsula, with one center in southern Greece and another one in Macedonia and southwestern Bulgaria
Variability coefficients for nut mass ranged from 24.59% for the Karlovac population to 35.84% for the Bosiljevo population

Summary

Introduction

Sweet chestnut (Castanea sativa Mill.) is a medium–large, monoecious insect- and wind-pollinated deciduous tree that belongs to the family Fagaceae [1] This species is characterized by oblong–lanceolate toothed leaves and spiky cupules containing one to three (seven) reddish-brown nuts with edible, creamy-white seeds, usually called kernels. Pollen and plant macrofossil analyses suggest that the most probable natural range of sweet chestnut is delimited by several macro-regions [5]: the Transcaucasian region, northwestern Anatolia, the Apennines on the Italian Peninsula, the hills of the Prealps in northeastern Italy with a possible extension into Slovenia, the Cantabrian coast in the Iberian Peninsula, and the Balkan Peninsula, with one center in southern Greece and another one in Macedonia and southwestern Bulgaria This was confirmed by several genetic studies [6,7,8,9,10,11,12]

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