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THE COMPARATIVE BIOLOGY OF CLOSELY RELATED SPECIES LIVING IN THE SAME AREA
Author(s) -
MCNAUGHTON I. H.,
HARPER JOHN L.
Publication year - 1960
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1960.tb06198.x
Subject(s) - hybrid , biology , botany , dominance (genetics) , genetics , gene
S ummary The hybrids Papaver dubium × P. rhoeas , and the reciprocal cross, have been produced by artificial cross‐pollination. The hybrids are not intermediate in character between the parents and are highly variable. Three main classes may be recognized although these intergrade: ( a ) forms which die in the rosette stage from a characteristic apical die‐back, ( b ) forms which lose apical dominance and become bushy, with chlorotic, distorted leaves and abortive flower buds—resembling certain virus syndromes (e.g. tomato bushy stunt), ( c ) forms which retain a degree of apical dominance and produce small open flowers, which are both male‐ and female‐sterile, in numbers much higher than in either parent. The hybrids are much less vigorous than the parents in the field, where they rarely survive under experimental conditions. Few previously recorded natural hybrids between these species can be accepted as valid, and most published descriptions of the hybrids seem to be based on aberrant specimens of the species, not on hybrids. Naturally occurring hybrids have been found near Oxford which conform well with hybrids produced artificially. The significance of these experiments and observations is discussed in relation to (1) the symptoms of virus infections, viroids and ‘Dauer‐modification’, (2) nature of breeding‐barriers between the species of Papaver , and (3) problems of the taxonomy of hybrids.