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B‐CHROMOSOMES, THEIR ORIGIN AND RELATION TO MEIOSIS IN INTERSPECIFIC LOLIUM HYBRIDS
Author(s) -
Hovin A. W.,
Hill Helen D.
Publication year - 1966
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1966.tb14026.x
Subject(s) - biology , meiosis , botany , lolium rigidum , hybrid , lolium multiflorum , lolium , genetics , poaceae , weed , herbicide resistance , gene
The following Lolium species were shown to have 14 chromosomes: L. canariensis Steud. (= L. gracile Parl.), L. loliaceum (Bory and Chaub.) Hand.‐Mazz., L. multiflorum Lam., L. perenne L., and L. temulentum L. B‐chromosomes in addition to the normal complement were observed during metaphase I and anaphase I for L. persicum Boiss. and Hohen., L. remotum Schrank, L. rigidum Gaud., L. strictum Presl. ( = L. rigidum ?), and for several synthesized interspecific hybrids. General absence of B‐chromosomes in diakinesis suggested that they originated by misdivision of A‐chromosomes during prometaphase I. The B‐chromosomes reached a maximum of eight but the number varied for microsporocytes of the same plant. B‐chromosomes appeared spontaneously in progenies from sibbing of hybrid plants without supernumeraries but were also eliminated in the F 2 from other sibbings. Degree of chromosome pairing during meiosis was unrelated to the subsequent presence of B‐chromosomes. Normal pairing of seven bivalents was typical for L. perenne × L. multiflorum, L. perenne × L. rigidum, L. multiflorum × L. loliaceum , and L. rigidum × L. loliaceum . Between five and seven bivalents were recorded for L. multiflorum × L. persicum, L. multflorum × L. remotum, L. multiflorum × L. strictum, L. rigidum × L. persicum, L. rigidum × L. remotum, L. rigidum × L. strictum , and L. rigidum × L. temulentum . The results indicated that these Lolium species have a common and generally undifferentiated genome suggesting relatively recent speciation.