Polymorphic chloroplast simple sequence repeat primers for systematic and population studies in the genus Hordeum

Area of Science:

• Genetics
• Plant Science
• Evolutionary Biology

Background:

• The genus Hordeum, encompassing cultivated barley (H. vulgare ssp. vulgare) and its wild progenitor (H. vulgare ssp. spontaneum), is a vital crop species.
• Understanding genetic diversity and evolutionary processes within Hordeum is crucial for crop improvement and conservation.

Purpose of the Study:

• To develop polymorphic chloroplast simple sequence repeat (cpSSR) primers for the genus Hordeum.
• To investigate cytoplasmic genetic diversity within cultivated and wild barley populations.
• To explore the evolutionary history of Hordeum species, particularly polyploids.

Main Methods:

• Development and application of polymorphic cpSSR primers across various Hordeum species.
• Analysis of intraspecific variation in cultivated barley (H. vulgare ssp. vulgare) and its wild progenitor (H. vulgare ssp. spontaneum).
• Comparative analysis of cytoplasmic diversity between different Hordeum subspecies, landraces, and cultivars.

Main Results:

• Successfully amplified polymorphic cpSSR products across a broad range of Hordeum species.
• Detected significant intraspecific variation in both cultivated and wild barley.
• Observed a notable decrease in cytoplasmic diversity from H. vulgare ssp. spontaneum to H. vulgare ssp. vulgare, and further reduction from landraces to cultivars, consistent with domestication.
• Identified potential evidence of reticulate evolution and cytoplasmic introgression in Hordeum brachyantherum polyploids.

Conclusions:

• The developed cpSSR primers are effective tools for studying genetic diversity in the genus Hordeum.
• Barley domestication has led to a reduction in cytoplasmic genetic diversity.
• Polyploid Hordeum species may have complex evolutionary histories involving cytoplasmic introgression.