Heritability of fruit and kernel traits in almond

The variability and heritability of several fruit and kernel traits were studied in 22 families of the almond breeding programme being developed at the SIA of Zaragoza. The traits studied included metric and non-metric parameters. The metric traits were weight, length (L), width (W), thickness (T) and their W/L and T/L ratios both for fruit and kernel, as well as the kernel percentage and the amount of double kernels. Non-metric traits included shape, surface type, and mucro presence both for fruit and kernel, as well as the presence of keel, presence and size of points on the shell, shell thickness, shell with a double layer, presence of furrows on the kernel, tegument colour and kernel taste. The highest heritabilities were observed for length, thickness, W/L and T/L ratios, shape, surface type and point size for the fruit, as well as for length and W/L and T/L ratios for the kernel. These results show a correlation of heritability of the same trait for fruit and kernel and that the shape and size of the fruit and kernel are highly heritable. Comparison with results reported previously for some of these traits show that our heritabilities are lower. This decrease could be due to the larger genetic diversity among the parents involved in these 22 progenies, as well as to the different growing conditions of the parents and the seedlings when considering the heritability by regression.