Polypodium Interjectum And P. × Mantoniae (Polypodiaceae) In The Polish Sudetes

Detailed analyses of micro- and macromorphological features of 247 specimens representing the Polypodium vulgare complex, combined with DNA content measurements, revealed the presence of tetraploid P. vulgare s.str., hexaploid P. interjectum and the pentaploid hybrid P. × mantoniae in the Polish Sudetes. For species identification, sporangium structure (number of indurated and basal annulus cells) was found to be the most stable and thus the most valuable and taxonomically significant character. The size of spores and stomata was related to taxon ploidy level, and helped to differentiate the examined taxa. Polypodium interjectum was identified from only one locality in the Pogórze Kaczawskie foothills; P. × mantoniae was more widely distributed, suggesting that it is rather common in the Polish Sudetes. Both newly reported taxa occur mainly on basic or neutral rock in sheltered, shaded or semi-shaded habitats.

Genome analysis of Elytrigia pycnantha and Thinopyrum junceiforme and of their putative natural hybrid using the GISH technique

Genomic in situ hybridization (GISH), using genomic DNA probes from Thinopyrum elongatum (Host) D.R. Dewey (E genome, 2n = 14), Th. bessarabicum (Savul. & Rayss) A. Löve (J genome, 2n = 14), Pseudoroegneria stipifolia (Czern. ex Nevski) Löve (S genome, 2n = 14), and Agropyron cristatum (L.) Gaertner (P genome, 2n = 14), was used to characterize the genome constitution of the polyploid species Elytrigia pycnantha (2n = 6x = 42) and Thinopyrum junceiforme (2n = 4x = 28) and of one hybrid population (2n = 5x = 35). GISH results indicated that E. pycnantha contains S, E, and P genomes; the first of these was closely related to the S genome of Ps. stipifolia, the second was closely related to to the E genome of Th. elongatum, and the third was specifically related to A. cristatum. The E and P genomes included 2 and 10 chromosomes, respectively, with S genome DNA sequences in the centromeric region. GISH analysis of Th. junceiforme showed the presence of two sets of the E genome, except for fewer than 10 chromosomes for which the telomeric regions were not identified. Based on these results, the genome formula SSPSPSESES is proposed for E. pycnantha and that of EEEE is proposed for Th. junceiforme. The genomic constitution of the pentaploid hybrid comprised one S genome (seven chromosomes), one P genome (seven chromosomes), and three E genomes (21 chromosomes). The E and P genomes both included mosaic chromosomes (chromosomes 1 and 5, respectively) with the centromere region closely related to S-genome DNA. On the basis of these data, the genome formula SPSESEE is suggested for this hybrid and it is also suggested that the two species E. pycnantha and Th. junceiforme are the parents of the pentaploid hybrid.Key words: GISH, Elytrigia pycnantha, Thinopyrum junceiforme, pentaploid hybrid, P genome.

Isoetes × truncata: a newly considered pentaploid hybrid from western North America

Three Isoetes found in Pyramid Lake, Jasper National Park, Alberta, constitute populations of tetraploid (2n = 44)I. maritima, hexaploid (2n = 66)I. occidentalis, and an abortive-spored, pentaploid hybrid (2n = 55) with intermediate morphological characteristics. Although the hybrid has been present in the lake since at least 1918, I. maritima and I. occidentalis were previously unknown in Alberta. The presence of these aquatics hundreds of kilometres from their next known populations in central British Columbia is suspected to reflect the floristic and faunal affinity of the Pyramid Lake area to biotic regions in the interior of British Columbia. Morphological, scanning electron microscopy, and cytological data are provided to support our conclusion that the Alaskan type material of I. × truncata is synonymous with the Pyramid Lake pentaploid. Investigations of similar taxa in western North America detected several I. occidentalis populations in Alaska where it was previously unknown. This represents the first report of a pentaploid Isoetes hybrid in North America and the first western North American hybrid to be described in detail. Key words: Isoetes, Isoetes maritima, Isoetes occidentalis, Isoetes × truncata, hybrid, Alberta, Alaska.

Chromosome relationships and morphological comparisons in the hybrids Avena hybrida × A. sativa and A. hybrida × A. maroccana

The morphology and chromosome pairing of the hexaploid hybrid Avena hybrida × A. sativa, and the pentaploid hybrid A. hybrida × A. maroccana are described in relation to their genomic affinities. The cytological data indicates a close relationship between the two hexaploid species, but does not provide sufficient information to place the relationship more specifically. Cytological data on the pentaploid hybrid indicates that A. hybrida is related to A. maroccana but more distantly than A. sterilis.

INTROGRESSION BETWEEN THE CULTIVATED HEXAPLOID OAT A. SATIVA AND THE TETRAPLOID WILD A. MAGNA AND A. MURPHYI

Introgression between the hexaploid (2n = 42) oat A. sativa and the newly discovered tetraploid (2n = 28) species A. magna and A. murphyi was studied by the rate of stabilization of chromosome number, restoration of fertility of pentaploid hybrid derivatives and the ultimate gene transfer between the tetraploid and the hexaploid levels. The complete self-sterility of the pentaploid F1 hybrids was overcome by massive back-pollination to the parental species. Great variation in chromosome number (12-48) was found among the viable F1 female gametes. Meiotically stable and reasonably fertile derivatives were selected only at the F2 of the BC and in a relatively small proportion. Gene transfer between the tetraploid and the hexaploid species was demonstrated by introducing the allele for nonshattering seed from the cultivated oat A. sativa to both A. magna and A. murphyi, and lemma hairiness from the tetraploids to the hexaploid level. The possible exploitation of introgression between the polyploid oats for breeding purposes has been pointed out and the potential of A. magna and A. murphyi as cultivated oats has been briefly discussed.