Why is vivipary an undesirable character for annual crop plants?

Annual plants complete their life cycle in one season, wherein seeds are produced, germinated and the mature plant hence produced, dies within the same season. In vivipary, seeds or spores germinate in situ on mature plants even before they are released which is not possible for annual plants as in them, the mature plants fail to store seeds. This is a result of it dying after seedproduction. Related Theory Seeds are structures that contain a young plant inside a protective coating. One reason why seed plants are so numerous is that they produce seeds. Seed plants do not need water in their environment to reproduce like seedless plants do. Even though different kinds of seeds look different from each other, they all have a similar structure. A seed has three important parts: an embryo, stored food, and a seed coat. All seed plants share two characteristics. They have vascular tissue and use seeds to reproduce. In addition, they all have body plans that include leaves, stems, and roots. Most seed plants live on land.