Aegilops uniaristata Vis. (Poaceae): typification and occurrence in Croatia

After 88 years, occurrence of Aegilops uniaristata Vis. (Poaceae) in Croatian flora was confirmed and its distribution is supplemented by new localities. It has been confirmed and its distribution supplemented by new localities. Populations of a few specimens were found in southern Istria, in the vicinity of the small town of Bale, in the village of Krnica and on the Rt Kamenjak promontory, growing within dry Mediterranean grasslands. Based on herbarium revision a lectotype from Visiani’s collection in herbarium PAD and an epitype from the herbarium W were designated.

Cytogenetic and molecular markers for detecting Aegilops uniaristata chromosomes in a wheat background

Aegilops uniaristata has many agronomically useful traits that can be used for wheat breeding. So far, a Triticum turgidum – Ae. uniaristata amphiploid and one set of Chinese Spring (CS) – Ae. uniaristata addition lines have been produced. To guide Ae. uniaristata chromatin transformation from these lines into cultivated wheat through chromosome engineering, reliable cytogenetic and molecular markers specific for Ae. uniaristata chromosomes need to be developed. Standard C-banding shows that C-bands mainly exist in the centromeric regions of Ae. uniaristata but rarely at the distal ends. Fluorescence in situ hybridization (FISH) using (GAA)8 as a probe showed that the hybridization signal of chromosomes 1N–7N are different, thus (GAA)8 can be used to identify all Ae. uniaristata chromosomes in wheat background simultaneously. Moreover, a total of 42 molecular markers specific for Ae. uniaristata chromosomes were developed by screening expressed sequence tag – sequence tagged site (EST–STS), expressed sequence tag – simple sequence repeat (EST–SSR), and PCR-based landmark unique gene (PLUG) primers. The markers were subsequently localized using the CS – Ae. uniaristata addition lines and different wheat cultivars as controls. The cytogenetic and molecular markers developed herein will be helpful for screening and identifying wheat – Ae. uniaristata progeny.

Distribution and characterization of Aegilops and Triticum species from the Bulgarian Black Sea coast

A total of 158 Aegilops-Triticum samples representing six Aegilops species (one diploid, four tetraploid and one hexaploid) and one diploid Triticum were collected along the Bulgarian Black Sea coast, and their distribution on the 350 km long coastal line was reported. The region south of Kamchia river, accepted as the middle point of the coast, was characterized by the greatest diversity of these wild relatives of wheat. The most widely distributed species in this area was Ae. geniculata. Ae. cylindrica was distributed only in north (Durankulak), while Ae. biuncialis and Ae. triuncialis were collected both north and south of Kamchia river. All samples of Ae. neglecta were hexaploid. Natural hybrids of goatgrass and wheat were found in Ae. cylindrica populations. Triticum monococcum ssp. aegilopoides had limited distribution in the south region. Aegilops uniaristata was recorded as a new species for the Bulgarian flora. Most of the samples expressed resistance to powdery mildew in seedling and adult stage, but all of them were polymorphic regarding the resistance to leaf rust (cultures 73760 and 43763). The study revealed additional data for the distribution of Aegilops and Triticum species in Bulgaria and their potential value as genetic resources in wheat improvement.

Structure of Aegilops ventricosa chromosome 6Nv, the donor of wheat genes Yr17, Lr37, Sr38, and Cre5

An Aegilops ventricosa Tausch (2n = 28, DvDvNvNv) subtelocentric chromosome added to wheat (Triticum aestivum L.) in a disomic addition line was found to carry the genes for resistance Yr17, Lr37, Sr38, and Cre5 already transferred onto chromosome 2AS of the wheat line VPM1. Previous works demonstrated that this Ae. ventricosa chromosome is translocated with respect to the standard wheat genome. The present investigations showed that this chromosome pre-existed in Ae. ventricosa and contains only chromatin specific to the N genome. Using biochemical markers and suitable cytogenetic materials including the monoisosomic addition line for the translocated long arm (6NvL–2NvS), its structure was defined as being 6NvSdel.6NvL–2NvS. It consists of a segment of the short arm 2Nv, containing the resistance genes, attached to a group 6 chromosome lacking a distal part of its short arm. The 2 re arrangements could already be present in Aegilops uniaristata Vis. (2n = 14, NN), the source of the Nv genome of Ae. ventricosa.Key words: wheat, Aegilops ventricosa, GISH, translocation, isochromosome.