Variation in fruit shape in three pear hybrid progenies

Digitised video images of fruits from three seedling families of pear were taken and eight height and width measurements calculated. Ratios between height and maximum width, height of maximum width and height, widths at 10% and 90% heights, and widths at 25% and 75% heights were calculated from the data and used as descriptions of fruit shape. The progenies segregated for each ratio about a continuous uni-modal distribution, which was Normal or nearly so. This would be expected if the characters of height and width are under polygenic control and inherited additively. The progenies showed a tendency away from pyriform towards round shape.