Genetic differences between natural populations of diploid and tetraploid Dactylis glomerata ssp. izcoi

Abstract

Twenty-one natural populations (thirteen tetraploids and eight diploids) of Dactylis glomerata ssp. izcoi (an Iberian endemic) were evaluated in the field for three consecutive years, using two clones per genotype, to separate genetic and environmental factors. Many traits showed significant differences between ploidy levels, but all of them overlapped. Therefore, it is justified to include both cytotypes in a subspecies in which tetraploids could be autopolyploids. In general, however, diploids had shorter stomatal guard cells, lower seed production and were later heading than tetraploids. Within tetraploids, most traits differed significantly between and within populations. There was less inter-and intrapopulation variation in the diploids. The range of plant dimensions exceeded that of former descriptions of the subspecies, bringing it closer to ssp. glomerata. Inland populations were not qualitatively different from one coastal population. Diploid populations showed less risk of hypomagnesemia than tetraploids.

Do pentaploid hybrids mediate gene flow between tetraploid Senecio disjunctus and hexaploid S. carniolicus s. str. (S. carniolicus aggregate, Asteraceae)?

“…This result contrasts the lack of differences in seedling survival discussed above and may indicate that even if individuals emerging from 5x5x crosses do not necessarily have a higher probability of dying, their growth is indeed compromised as compared to the other treatments, even if the backcrosses with the parents will certainly be aneuploid. The size of 6x5x seedlings exceeded that of 4x5x seedlings (Table 2), most probably because higher ploidy levels result in bigger cell sizes and thus in taller plants (Lumaret et al 1987;Lindner and Garcia 1997). A positive association between plant size and ploidy level was also observed in the S. carniolicus species group (Flatscher et al 2015).…”

Complete Chloroplast Genomes of 14 Subspecies of D. glomerata: Phylogenetic and Comparative Genomic Analyses

“…The genus contains one species and numerous subspecies that have different ploidy levels [ 2 ]. Orchardgrass is native to Eurasia and northern Africa, although it has been introduced to nearly every continent and utilized as excellent cool–season forage for the livestock industry that requires forage [ 3 ]. In China, orchardgrass has already become an elite forage crop for mixed pasture construction and rocky desertification improvement in southwestern regions.…”

Genotyping by Sequencing and Plastome Analysis Finds High Genetic Variability and Geographical Structure in Dactylis glomerata L. in Northwest Europe Despite Lack of Ploidy Variation

“…Sometimes these diploids are taxonomically segregated as separate species or infraspecific taxa but they intergrade with each other and the tetraploid forms, in a polyploid complex. Triploids, pentaploids and hexaploids were reported [24][25][26][27][28][29] [24,25,26,27,28,29] and genome size varied with altitude in natural tetraploid populations [30].…”