Transgenic Male Sterility Permits Efficient Recurrent Selection in Autogamous Crops

In recent decades, yield improvements of major autogamous crops have slowed. Contrastingly, the yield of maize (Zea mays L.) has continuously increased through breeding based on wide genetic diversity and recurrent selection. Recurrent selection is very powerful and is a suitable breeding system for outcrossing (allogamous) crops. To achieve recurrent selection of autogamous crops, some progress has been made in rice (Oryza saliva L.), sorghum [Sorghum bicolor (L.) Moench], and soybean [Glycine max (L.) Merr.] using genetic male sterility. However, this approach has not provided major improvements for the breeding of autogamous crops, because it is laborious or based on specific properties of the crops. To prevent this from becoming a bottleneck for the use of recurrent selection in autogamous crops, the author devised an efficient recurrent selection system based on transgenic male sterility, herbicide tolerance, and conditional lethality suitable for use with autogamous crops. This system offers three advantages. First, it can be applied on a large scale while permitting continuous recurrent selection. Second, the cultivars that are the final products of this breeding do not contain the transgenes introduced by this system. Third, the transgenic plants cannot produce pollen and therefore cannot cross naturally with cultivated crops or related wild species. This paper proposes an efficient recurrent selection for autogamous crops using transgenic male sterility.