title: High frequncies of fertilization and embryo formation in hexaploid wheat x Tripsacum dactyloides crosses.
abstract: The Hexaploid wheat variety Fukuho was crossed with Tripsacum dactyloides (2n=4x=72). The total fertilization frequencies for the egg cell, polar nuclei, and both, were 58.3%, 26.8% and 58.9% of the 168 ovaries examined. However, the fertilization frequency of single polar nuclei was much lower at only 0.6%. The total frequency of fertilization was higher than that in wheat x maize crosses. A total of 49 hexaploid wheat varieties, including Hope carrying the dominant genes Kr1 and Kr2, were crossed with T. dactyloides, and most gave embryos. The embryoformation frequencies ranged from 0.5% to 59.0%. A higher frequency of 32.0% embryo formation was obtained following pollination of the variety Hope. In comparison with embryo formation in wheat x maize crosses the difference of embryo-formation frequencies between the two crosses was significant. The results of high frequencies of fertilization and embryo formation in wheat x T. dactyloides crosses indicated that the Kr genes are as inactive in wheat x T. dactyloides, as they are in wheat x maize crosses, and also that the efficiency of fertilization and embryo formation is higher in wheat x T. dactyloides than in what x maize crosses. The potential of wheat x T. dactyloides crosses for wheat haploid production and wheat improvement is discussed.
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics, The Chinese Academy of Sciences, 100101, Beijing, China.
authors.forename: D W
authors.initials: DW
authors.lastname: Li
authors.forename: J W
authors.initials: JW
authors.lastname: Qio
authors.forename: P
authors.initials: P
authors.lastname: Ouyang
authors.forename: Q X
authors.initials: QX
authors.lastname: Yao
authors.forename: L D
authors.initials: LD
authors.lastname: Dawei
authors.forename: Q
authors.initials: Q
authors.lastname: Jiwen
authors.forename: O
authors.initials: O
authors.lastname: Ping
authors.forename: Y
authors.initials: Y
authors.lastname: Qingxiao