Male sterility in field beans (Vicia faba L.). IV. Use of cytoplasmic male sterility in the production of F1 hybrids, and their performance in trials

1. A method of producing hybrid beans with the aid of a cytoplasmic male-sterile is described. 2. Most of the requirements of large scale production of hybrid seed can be met: use of genetic markers showed that the male sterility allowed 100% cross fertilization; there was no evidence of a deficiency of insect pollinators near Cambridge; and fertility restoring lines are available. 3. The importance of being able to maintain a high level of sterility in the female parent line is emphasized. Methods of improving the proportion of sterile plants in the sterile phase of an inbred are discussed. The tolerable level of fertility in progenies of sterile parents depends on the level of sterility necessary in the female parent of the final cross. Five inbreds are being handled with less than 2% of fertile plants in their sterile phase.