Aegilops sharonensis:Origin, genetics, diversity, and potential for wheat improvement

Abstract

Aegilops sharonensis Eig (Sharon goatgrass; section Sitopsis) is an annual diploid grass species growing endemically in the coastal plains of Israel and southern Lebanon. It is a wild relative of wheat, with a genome closely related to the B genome of cultivated bread wheat. With the most limited distribution of any species in the genus Aegilops, Ae. sharonensis is rapidly losing its habitats, owing to the combined effects of modern agricultural intensification and expansion of urban and industrial areas. Aegilops sharonensis is known to be a rich source of genes providing resistance to important wheat diseases and abiotic stresses, but it has not been widely exploited. The presence of gametocidal genes that control preferential transmission of chromosome 4Ssh increases the difficulty of introgressing genes from Ae. sharonensis into wheat. However, successful introgression of the genes for resistance to leaf rust, stripe rust, and powdery mildew has been achieved. Studies on genetic and phenotypic diversity indicated that Ae. sharonensis is a highly diverse species, comparable with others that have a wider geographic distribution and more variable environments. Targeting the regions and sites with the highest diversity in Ae. sharonensis will facilitate the capture of the greatest variability and also the identification of novel and diverse genes for wheat improvement.

Exploring morphological variation in tomato (Solanum lycopersicum): A combined study of disease resistance, genetic divergence and association of characters

“…As the magnitude of diversity and availability of plant resources are vital for crop improvement (Govindaraj et al, 2015), estimation of genetic diversity and relationships between crop germplasms is the key step (Rafalski, 2011) and the loss of genetic diversity is : Not significant a major danger for the survival and breeding of crop species (Olivera and Steffenson, 2009). Phenotypic data have been used to compare individual genotypes and populations of crop species with the aim of optimizing characterization, determining characters variations, associations and establishing genetic relationship within species.…”

Reducing the size of an alien segment carrying leaf rust and stripe rust resistance in wheat

“…Exceptional is Aegilops speltoides that provided 6 leaf rust resistance genes Lr28, 35, 36 47 51 and 66 [9]. Aegilops sharonensis Eig (Sharon goatgrass) was found to possess resistance against different wheat diseases including leaf, stripe and stem rusts, powdery mildew, tan spot and spot blotch [12] but has not been widely exploited [13]. In 2006, Marais et al reported on transferring resistance to leaf rust (Lr56) and stripe rust (Yr38) to chromosome 6A of wheat, while recently, Millet et al [14] reported on introgressing resistance to the devastating stem rust race TTKSK (Ug99) from Ae.…”

Development of a genetic linkage map for Sharon goatgrass (Aegilops sharonensis) and mapping of a leaf rust resistance gene

“…Introgressing resistance genes from Ae. sharonensis into wheat is not trivial because it involves special cytogenetic techniques and dealing with gametocidal genes that control the preferential transmission of certain chromosomes (Olivera and Steffenson 2009). Additionally, as with all exotic sources of resistance, linkage drag can be a problem.…”

“…Additionally, as with all exotic sources of resistance, linkage drag can be a problem. Still, a number of researchers have successfully transferred genes from this species into wheat (Olivera and Steffenson 2009). Marais et al (2006) reported the introgression of a leaf rust and stripe rust resistance gene from Ae.…”