F1 Hybrid Breeding Using Genome Information

Abstract

Most radish cultivars on the Japanese and Korean markets today are F1 hybrids. In the other countries, F1 cultivars are also increasing. The radish root is a product of field conditions and genotype responses to environment and season. A marketable product depends on a sustained balance of vegetative characters throughout the growth. Breeding for the root size and shape, the disease resistance, and physiological disorder tolerance must maintain the optimum balance of these characters under each cropping environment and consider their heterosis. In vegetable F1 hybrid breeding, characters relevant to seed production are evaluated and selected during the reproductive stage, after the selection of vegetative characters. Therefore, the identification of selection markers for seed production characters can greatly improve selection efficiency. Even if a cross has improved vegetative characters, it is not grown if its parents cannot stably produce large amounts of high-purity F1 seeds with a high germination rate. This chapter describes the current state of F1 hybrid breeding and future needs.