Skip to main content
ARS Home » Research » Publications at this Location » Publication #63516


item Campbell, Travis

Submitted to: Canadian Journal of Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Hybrid vigor is achieved by mating (crossing) parents that were selected for their ability to combine in a manner which produces vigorous progeny. To assure that crossing occurs, breeders either emasculate the plant that is to receive the pollen (the "female" parent), select a "female" parent that produces sterile pollen, or one that produces viable pollen but cannot pollinate itself (termed self-incompatible). The first two method have not proved economically feasible for the production of hybrid alfalfa seed. This paper addresses the use of self-incompatibility for production of hybrid alfalfa. New evidence that self-incompatibility is inherited in alfalfa is presented, indicating that varieties of alfalfa could be produced that would have fewer self-pollinated progeny and thus have the potential to exhibit greater hybrid vigor. Alfalfa is the most important hay crop in the U.S. and is essential to the dairy farmer. This research indicates that alfalfa varieties with improved hybrid vigor could be produced that would allow the farmer to produce more hay/acre for his animals. The results will be used for researchers working to produce hybrid alfalfa.

Technical Abstract: Self-incompatibility (seeds/pod and seeds/flower tripped) was evaluated in the growth chamber (27oC) using a 6 x 6 factorial design. Parents represented a broad range of self-compatibility and were selected on the basis of stability of autogamous seed production in the greenhouse and growth chamber. Additive genetic variation appeared to be most important, , indicating that a mass selection scheme such as recurrent phenotypic selection would be effective in increasing levels of self-incompatibility in at least some alfalfa populations. Narrow-sense heritability estimates for seeds/pod and seeds/flower tripped were 0.23 (S.E.=0.09) and 0.29 (S.E.=0.06), respectively. There is a direct relationship between autogamous seed production and pollen production, however, results of this experiment indicate that there may be considerable variation in pollen production, germination and vigor among self-incompatible clones. It may be possible to increase seeds/pod slightly through breeding without a commensurate increase in autogamy. Increased seed set resulting from self-incompatible x self-incompatible crosses could be a function of hybrid vigor in pollen tube growth as well as in improved pollen germination.