BIOMETRICAL METHODS TO REINFORCE SELECTION EFFICIENCY IN BREEDING PROGRAMS FOR HAZELNUT (CORYLUS AVELLANA L.) CROP IMPROVEMENT

Heritability has a predictive role for determining the breeding value of the hazelnut parents using their phenotypic value; moreover, it expresses the proportion of the total variance attributable to the average effects of genes in the parents which have been transmitted to the progeny and are available for selection. The regression of half-sib (HS) offspring compared to the mother plant from accessions of ‘Tonda Gentile Romana’, ’Nocchione’, ‘Tonda Gentile delle Langhe’, ‘Nociara’, ‘San Giovanni’, ‘Longue d’Espagne’, ‘Sivri A’, and ‘Karidati’, was used as a method to estimate heritability for the following traits: nut weight, nut width, nut shape index, seed weight, husk length and nut length of hazelnut landraces. Nut length showed the highest and significant offspring-one parent regression coefficient. Overall, the 46 HS-offspring plants analyzed showed larger variation than the parental plants. The first two principal components (PC1 and PC2), that explain 39% and 29% respectively of the observed variability for the eight fruit and seed characters, indicated positive correlation of PC1 scores with the length and shape of fruits and seeds. Therefore, the variability of fruit length and shape in the offspring, attributable to significant average effects of genes inherited from the parents, is available for screening and selection of HS-offspring plants to identify ortets to derive novel clones expressing new seed shape features. The progeny from ‘Longue d’Espagne’and ‘Tonda Gentile Romana’ are the most promising for selection progress.