Generation and molecular marker and cytological characterization of wheat – Secale strictum subsp. anatolicum derivatives

Cereal rye and its wild forms are important sources of genetic diversity for wheat breeding due to their resistances to biotic and abiotic stresses. Secale strictum subsp. anatolicum (Boiss.) K. Hammer (SSA) is a weedy relative of cultivated rye, S. cereale. Meiotic chromosome pairing in F1 hybrids of SSA and S. cereale reveals strong genomic affinity between the two genomes. A study of the transferability of S. cereale sequence-based markers to SSA and hexaploid triticale demonstrated their applicability for tracing SSA chromatin in wheat. The transferability of the markers was over 80% from homoeologous groups 1, 2, and 3, and greater than 70% from groups 4 to 7. This study focused on the generation and molecular and cytogenetic characterization of wheat–SSA alien derivatives. Twelve were identified using combinations of non-denaturing fluorescence in situ hybridization (ND-FISH), genomic in situ hybridization (GISH), and molecular marker analysis. All SSA chromosomes, except 3Ra and 6Ra, were transferred to wheat either in the form of monosomic additions (MA), mono-telosomic additions (MtA), double-mono-telosomic additions (dMtA), or double-monosomic additions (dMA). The germplasm developed in this study will help to enhance the genetic base of wheat and facilitate molecular breeding of wheat and triticale.

Production of Alien Addition Lines in Polyploid Bunching Onion (Allium fistulosum) Carrying 1A Chromosome(s) of Shallot (Allium cepa) and Their Application to Breeding for a New Vitamin C-Rich Vegetable

Eight Allium fistulosum L.–Allium cepa L. Aggregatum group (shallot) monosomic addition lines (2n = 17, FF+1A–FF+8A) have been useful in revealing the effects of single alien chromosomes from A. cepa on the production of l-ascorbic acid in the leaf tissue of A. fistulosum. In this study, the determination of ascorbic acid content revealed that the incorporation of alien chromosome 1A into a diploid background of A. fistulosum increased the internal ascorbic acid content of the leaf blade tissue. We produced a 1A disomic addition in the tetraploid of A. fistulosum (2n = 34) and demonstrated high-frequency transfer of the alien chromosome in crosses with A. fistulosum. Five plants of the 1A disomic additions were regenerated via apical meristem culture of the FF+1A on a Murashige and Skoog medium containing colchicine. These 1A disomic additions showed partial fertility for female and male gametes. Most of the progenies from selfing of the 1A disomic additions and reciprocal crossing with A. fistulosum possessed chromosome 1A. Interestingly, 64% (18 of 28) of the plants obtained from the reciprocal crosses were 1A monosomic additions in a triploid background of A. fistulosum. These monosomic additions were more vigorous and vitamin C-rich than euploid plants of A. fistulosum.

Transmission of alien chromosomes from selfed progenies of a complete set of Allium monosomic additions: the development of a reliable method for the maintenance of a monosomic addition set

Selfed progeny of a complete set of Allium fistulosum – Allium cepa monosomic addition lines (2n = 2x + 1 = 17, FF+1A–FF+8A) were produced to examine the transmission rates of respective alien chromosomes. All eight types of the selfed monosomic additions set germinable seeds. The numbers of chromosomes (2n) in the seedlings were 16, 17, or 18. The eight extra chromosomes varied in transmission rate (%) from 9 (FF+2A) to 49 (FF+8A). The complete set of monosomic additions was reproduced successfully by self-pollination. A reliable way to maintain a set of Allium monosomic additions was developed using a combination of two crossing methods, selfing and female transmission. FF+8A produced two seedlings with 18 chromosomes. Cytogenetical analyses, including GISH, showed that the seedlings were disomic addition plants carrying two entire homologous chromosomes from A. cepa in an integral diploid background of A. fistulosum. Flow cytometry analysis showed that a double dose of the alien 8A chromosome caused fluorescence intensity values spurring in DNA content, and isozyme analysis showed increased glutamate dehydrogenase activity at the gene locus Gdh-1.Key words: Allium cepa, Allium fistulosum, monosomic addition, disomic addition, transmission rate.

Rf genes restore fertility in wheat lines with cytoplasms of Elymus trachycaulus and E. ciliaris

Alloplasmic euploid wheat lines with the cytoplasm of Elymus trachycaulus (2n = 4x = 28, StStHtHt) and Elymus ciliaris (2n = 4x = 28, ScScYcYc) are male sterile and have reduced vigor. Fertile alloplasmic wheat plants are also recovered, but they always contain complete or partial chromosome additions of 1Ht or 1St (in E. trachycaulus derived lines) or 1Yc (in E. ciliaris derived lines) with specific Elymus gliadin genes (Gli-Ht1, Gli-St1, Gli-Yc1) and fertility restoration (Rf) genes. The Rf genes on 1Ht 1St and 1Yc were named as Rf-Ht1, Rf-St1, and Rf-Yc1, respectively. In this study, we crossed different disomic addition lines with one another to produce double monosomic additions either in E. trachycaulus or E. ciliaris cytoplasm. The chromosome constitution, transmission, and fertility of the selfed and backcrossed progenies of three double monosomic additions with 21″ + 3BS∙1YcS′ + 1HtS∙1HtS′ (cytoplasm from E. trachycaulus), 21″ + 3BS∙1YcS′ + 1HtS∙1HtS′ (cytoplasm from E. ciliaris), and 21″ + 3BS∙1YcS′ + 7AL∙S-1StS′ (cytoplasm from E. ciliaris) were analyzed. The results indicated that (i) Rf-Ht1 and Rf-St1 on 1Ht and 1St restored fertility to wheat with E. ciliaris cytoplasm; (ii) Rf-Yc1 on 1Yc restored fertility to wheat with E. trachycaulus cytoplasm; (iii) cytoplasms of E. ciliaris and E. trachycaulus are closely related; and (iv) certain E. trachycaulus and E. ciliaris chromosomes show preferential transmission.Key words: Elymus, Rf genes, wheat–Elymus hybrids, cytoplasmic genetics, genome evolution.