Reproductive relationships between taxa morphologically close to Elymus caninus (Poaceae: Triticeae)

Area of Science:

• Botany
• Genetics
• Evolutionary Biology

Background:

• Hybridological studies are crucial for understanding plant reproductive relationships.
• The taxonomic status of species close to Elymus caninus, including E. prokudinii, E. viridiglumis, and E. goloskokovii, requires clarification within the E. caninus complex.
• Investigating reproductive compatibility and gene flow is key to defining species boundaries.

Purpose of the Study:

• To determine the reproductive relationships and integration level of E. goloskokovii, E. prokudinii, and E. viridiglumis into the E. caninus complex.
• To analyze the inheritance patterns of key diagnostic traits in interspecific hybrids.
• To assess the potential for introgression and clarify the taxonomic status of the studied biotypes.

Main Methods:

• Hybridization experiments were conducted using natural parental biotypes from Russia and Kazakhstan.
• Seed fertility was assessed in F1 and F2 generations of various crosses.
• Inheritance of lemma traits (trichomes, awn length) was analyzed.
• Morphological and chorological data were used to evaluate species status.

Main Results:

• High seed fertility (60-90%) was observed in natural parental biotypes.
• Hybrids from closely related habitats showed the highest seed setting in F1.
• Combinations involving E. caninus, E. viridiglumis, and E. goloskokovii exhibited high fertility (55.6% and 46.1%).
• Digenic and monogenic inheritance were observed for trichomes and awn length, respectively.
• High hybrid fertility and intermediate F2 forms suggest potential for interspecific introgression.
• E. caninus and E. mutabilis were confirmed as distinct species based on lower hybrid fertility and other criteria.

Conclusions:

• E. goloskokovii, E. prokudinii, and E. viridiglumis form a single recombination gene pool with E. caninus, supporting their classification as intraspecific taxa (E. caninus s. l.).
• The study demonstrates the possibility of interspecific introgression in natural populations where these species co-occur.
• E. caninus and E. mutabilis are recognized as separate species, despite potential gene flow, based on distinct reproductive and morphological characteristics.