Grape: Seeds

Seeds, pepins in French, of grapes vary in size and shape between varieties; for example, those in muscat blanc à petits grains are about 5 mm long while those in the table grape Waltham Cross are nearly 10 mm. Their number per berry tends to be a characteristic for each variety with one or two predominating. Four is possible since each carpel bears two ovules; however, some freak Alphonse Lavallée (Ribier) berries with double the number of carpels may have eight seeds. Often, incompletely developed seed structures occur, called stenospermic (thin-seeded), alongside fully developed seeds. The greater the number and amount of seed development, the larger the berry; this relationship is largely a reflection of differences in amount of cell division in the pericarp. The plant hormone gibberellin may substitute for the berry-enlarging effect of seeds, as it is when Sultana is grown for the table, for example.