Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: 3/15/2005
Publication Date: 3/15/2005
Citation: Hu, J., Miller, J.F., Chen, J., Vick, B.A. 2005. Preliminary observation on a spontaneous tricotyledonous mutant in sunflower. Sunflower Research Workshop Proceedings. 27th Sunflower Research Workshop, January 12-13, 2005, Fargo, ND. Available: http://www.sunflowernsa.com/research/research-workshop/documents/Hu_Tricotyledonous_05.pdf Interpretive Summary: Normal sunflower seedlings have two cotyledons. This paper report the observations on a sunflower mutant which produced three cotyledons. The mutant was found in the progeny of our breeding program. We found that this trait in heritable since continued self-pollination for four generations increased the percentage of seedling with three cotyledons from 2% to about 50% among the progeny. None of the mutant produced uniform three cotyledon progeny suggested that this gene has low penetrance. Additional studies are needed to elucidate the genetic base of this peculiar phenotype.
Technical Abstract: This report documents the tricotyledonous phenotype in sunflower. The mutant was found in a BC3F2 population developed for incorporating sulfonylurea (SU) herbicide resistance into cultivated sunflower. Progeny tests were carried out for three consecutive generations to study the inheritance of this anomalous characteristic under both greenhouse and field conditions during the past two years. It was interesting to observe that tricotyledonous seedlings also produced true leaves in sets of three at the first few nodes. The frequency of tricotyledonous phenotype increased from approximately 2% in the F2 generation to about 50% in the F5 generation (34 of 71). This suggested that this peculiar phenotype might result from recessive genes of low penetrance. Additional studies are needed to elucidate its genetic base.