Inheritance, distribution and biology of andromonoecy in the agamic complex of the Maximae (Panicoideae)

1999 ◽  
Vol 98 (3-4) ◽  
pp. 622-627 ◽  
Author(s):  
B. Assienan ◽  
M. Noirot
Keyword(s):  
Agamic Complex

Quantitative Morphology of the Amelanchier Agamic Complex (Rosaceae) at a Maine Site

1998 ◽  
Vol 23 (1) ◽  
pp. 31 ◽  
Author(s):  
Alison C. Dibble ◽  
Wesley A. Wright ◽  
Christopher S. Campbell ◽  
Craig W. Greene
Keyword(s):  
Quantitative Morphology ◽  
Agamic Complex

scholarly journals Co-occurrence of related asexual, but not sexual, lineages suggests that reproductive interference limits coexistence

2017 ◽  
Vol 284 (1868) ◽  
pp. 20171579 ◽  
Author(s):  
Jeannette Whitton ◽  
Christopher J. Sears ◽  
Wayne P. Maddison
Keyword(s):  
Reproductive Success ◽  
North American ◽  
Community Assembly ◽  
Reproductive Interference ◽  
Limiting Similarity ◽  
Viable Pollen ◽  
Agamic Complex ◽  
The North ◽  
Strong Asymmetry

We used randomizations to analyse patterns of co-occurrence of sexual and apomictic (asexual) members of the North American Crepis agamic complex (Asteraceae). We expect strong asymmetry in reproductive interactions in Crepis : apomicts produce clonal seeds with no need for pollination and are not subject to reproductive interference from co-occurring relatives. However, because they still produce some viable pollen, apomicts can reduce reproductive success of nearby sexual relatives, potentially leading to eventual local exclusion of sexuals. Consistent with this, randomizations reveal that sexuals are over-represented in isolated sites, while apomicts freely co-occur. Incorporation of taxonomic and phylogenetic evidence indicates that this pattern is not driven by local origins of asexuals. Our evidence that patterns of local co-occurrence are structured by reproductive interference suggests an underappreciated role for these interactions in community assembly, and highlights the need for explicit tests of the relative contributions of ecological and reproductive interactions in generating patterns of limiting similarity.

Hybridization (N + N and 2N + N) of Facultative Apomictic Species in the Pennisetum Agamic Complex

1992 ◽  
Vol 153 (3, Part 1) ◽  
pp. 466-470 ◽  
Author(s):  
E. C. Bashaw ◽  
M. A. Hussey ◽  
K. W. Hignight
Keyword(s):  
Agamic Complex ◽  
Apomictic Species

MEIOSIS AND POLYPLOIDY IN ONTARIO SPECIES OF CRATAEGUS IN RELATION TO THEIR SYSTEMATICS

1979 ◽  
Vol 21 (2) ◽  
pp. 231-241 ◽  
Author(s):  
M. Muniyamma ◽  
J. B. Phipps
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Pollen Sterility ◽  
Southern Ontario ◽  
Agamic Complex ◽  
Species Complexes ◽  
Extensive Documentation ◽  
Meiotic Irregularities ◽  
The Common ◽  
Taxonomic Studies

Chromosome number determinations of 68 accessions of about 20 species in 11 series of Crataegus (hawthorn), Rosaceae, occurring in southern Ontario are presented. This is the first extensive documentation of chromosome numbers in North American Crataegus since Longley's (1924) account which was based on sectioned material. Our results, taken in the context of our cytological work proving the presence of apomixis in the genus, and taxonomic studies, clearly establish that in Ontario Crataegus is part of an extensive agamic complex consisting of diploids (2n = 34), polyploids (3x and 4x) and some aneuploids. Cytological observations of the triploids (2n = 51) and tetraploids (2n = 68) that have indicated the occurrence of meiotic irregularities and various degrees of pollen sterility in some of the polyploid taxa studied, underline the significance of apomixis in Crataegus evolution. One of the common Ontario species, C. punctata, is shown to be a probable sexual diploid and further cytological work should now be concentrated on particular species complexes.

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