Hybrid Seeds

seeds produced by crossing plants belonging to different forms, varieties, lines, species, and genera. Because of heterosis, hybrid seeds often give higher yields than non-hybrid seeds. Hybrid seeds of corn, sugar beets, sorghum, vegetables, and some fodder grasses are widely used in Soviet agriculture. The possibility of using hybrid seeds of wheat, oil-producing plants, and other plants is under study. Hybrid seeds of the first generation are generally sown. The productivity of seeds of the second and subsequent generations decreases sharply. A specialized network of seed-producing farms has been organized to grow hybrid corn seeds, techniques for treating them have been developed. Because of the application of cytoplasmatic male sterility, hybrid corn seeds are grown without manual labor to remove the panicles. Hybrid sugar beet seeds are obtained by artificial crossing or free wind pollination. To obtain hybrid seeds of triploid varieties, the ratios of the rows are one row of tetraploid varieties to three or four rows of diploid varieties and one row of polyspermous varieties to five or four rows of monospermous varieties. When hybrid seeds of self-pollinating vegetable crops are grown, there is no need for castration because sterile forms are used (for example, tomatoes). In the case of cucumbers, dioecious varieties are used as maternal forms.