Search for genes affecting quantitative traits in experimental populations of hazelnut (Corylus avellana L.)
A graphical approach coupled to a goodness-of-fit chi-square test has been used to infer the number of genes affecting quantitative traits displaying high heritability in an experimental progeny of hazelnut. The full-sib (FS) progeny was obtained from the 'Tonda Gentile Romana' × 'Nocchione' hybridization. The frequency distribution of the observed phenotypic values for nut weight was trimodal. Seed weight, seed and nut length, seed and nut width, seed shape index (seed length/seed weight), nut shape index (nut length/nut weight) displayed a bimodal frequency distribution. The segregation patterns underlying the observed trimodal frequency distribution (null hypothesis H0-a) can be explained by a single biallelic locus, with additive allele effects, which was heterozygous (A1A2) in both the parents. The bimodal frequency distribution was attributed (null hypothess H0-b) to a dihybrid segregation at two independent loci expressing complementary epistasis, with both parents being AaBb. After the goodness-of-fit chi-square test, H0-a was not rejected for nut weight and H0-b was not rejected for seed weight, seed and nut length, seed and nut width, seed shape index (seed length/seed weight), nut shape index (nut length/nut weight). The single nucleotide polymorphism (SNP) molecular markers detected by a genotype-by-sequencing approach in the same FS progeny will help mapping the loci involved in the simple inheritance pattern displayed by size and weight of seeds and nuts.
Pitoni, A., Vittori, D. and De Pace, C. 2017. Search for genes affecting quantitative traits in experimental populations of hazelnut (Corylus avellana L.). Acta Hort. (ISHS) 1172:375-380
heritability, quantitative traits, simple inheritance, seed weight, seed size