Original scientific paper
The variability of european sweet chestnut (Castanea sativa Mill.) in the region of northwest Croatia according to morphology of fruits
Igor Poljak
; Šumarski fakultet Sveučilišta u Zagrebu
Marilena Idžojtić
; Šumarski fakultet Sveučilišta u Zagrebu
Marko Zebec
; Šumarski fakultet Sveučilišta u Zagrebu
Nikola Perković
; Šumarski fakultet Sveučilišta u Zagrebu
Abstract
The sweet chestnut (Castanea sativa Mill.) is an indigenous noble hardwood growing in the forests of the hilly area of continental Croatia, in Istria, and on the islands of Krk and Cres. As it grows in different ecological conditions, particularly edaphic and climate, and in different forest communities, one can assume there is a difference in the variability of populations. In the last few decades, chestnut blight (Cryphonectria parasitica /Murr./ Barr.) has been causing the drying and decay of sweet chestnut trees, while its management is significantly influenced by man, which could lead to the loss of genetic diversity. For that reason, the sweet chestnut is on the list of priority species for the conservation of genetic resources. Success of the measures for the conservation of genetic resources requires insights into the existing variability. For that purpose, the variability of sweet chestnut fruits was investigated in the region of Northwest Croatia using a morphometric analysis.
The fruits were collected from five populations (Figure 1), during October of 2010. The populations were represented with 20 trees each, and each tree with 10 fruits. In total, 1000 fruits and 10 morphological characteristics (Figure 2) were analysed and their ratios calculated.
The results of the descriptive statistical analysis are presented in Table 1, by population (N = 200) and overall, for all populations together (N = 1000). The average weight of fruits for the 5 investigated populations was 8.3 g. The research conducted proved the variables describing the shape of the fruit and the hilum, and the ratio between the length and width of the hilum and the length and width of the fruit to be the least variable characteristics. Furthermore, lower variability coefficients are proper to the height and width of the fruit, while the thickness of the fruit was proven to be a characteristic of medium variability. High variability coefficients, from 26.3 % for the Samobor Mountains population to 40.1 % for the Kalnik population, were obtained for fruit weight. The most variable characteristics proved to be the variables pertaining to the number and length of intrusions and their ratio to the fruit thickness.
The trees within populations differ significantly in all analysed properties, while the differences between populations are signficant for the majority of investigated characteristics (Tables 2 and 4). For the majority of measured characteristics it was found that the largest share of variability is dependent on the variability of trees within the population (Table 3). Differences between populations account for the smallest share of variability.
A cluster and discriminant analysis (Tables 5 and 6, Figures 3 and 4) established that mutually most similar populations are Samobor Mountains and Markuševac Mountain, followed by the Ivanščica population. Next is the Macelj population characterised by largest fruits, and the Kalnik population that differs the most from the other investigated populations. The Kalnik population is the only one present in a sweet chestnut forest with sessile oak (Querco-Castanetum sativae Horvat 1938) and belongs to the group of acidophilic and thermophilic forests, while the remaining four analysed populations belong to sweet chestnut forests of mesophilic character.
Keywords
Castanea sativa Mill.; variability; fruits; Northwestern Croatia
Hrčak ID:
91430
URI
Publication date:
31.10.2012.
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