L. Goulao et al., Comparison between phenetic characterisation using RAPD and ISSR markers and phenotypic data of cultivated chestnut (Castanea sativa Mill.), GEN RESOUR, 48(4), 2001, pp. 329-338
Patterns of phenotypic and phenetic variability in six Portuguese cultivars
of chestnut (Castanea sativa Mill.) are evaluated. Morphological character
isation was based on the quantification of seventeen traits. Variance analy
sis showed significant differences among cultivars, and cultivar x year for
all the traits studied, and trees within cultivars showed also some signif
icant differences for some of the morphological variables. A significant co
rrelation was obtained between length of the leaf blade and the percentage
of unisexual and androgynic inflorescence with the effective thermal index,
accumulated rainfall from April to October and from July to October, or th
e accumulated temperature below seven during the dormant period. Principal
Component and cluster analysis were performed to group the cultivars, accor
ding to their similarity coefficients. For molecular characterisation, 125
RAPD and 157 ISSR polymorphic markers were amplified using 28 and 7 primers
respectively. High level of congruence among the two marker systems (r = 9
0.5%) was obtained from comparison of phenetic similarities based on the pe
rcentage of shared fragments. ISSR markers revealed important advantages ov
er RAPDs, due to a high effective multiplex ratio (12.5 for ISSR compared w
ith 2.2 for RAPD analysis) and reproducibility. Although morphological and
molecular results are comparable, slight differences are showed in cluster
analysis UPGMA dendrograms. Molecular analysis explained homonym situations
among 'Martainha' and 'Longal' cultivars in Portugal.