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CHROMOSOME DIFFERENTIATION IN SEVERAL SPECIES OF MELILOTUS
Author(s) -
Shastry S. V. S.,
Smith W. K.,
Cooper D. C.
Publication year - 1960
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.1537-2197.1960.tb07144.x
Subject(s) - biology , hybrid , meiosis , officinalis , melilotus , botany , sterility , chromosome , pollen , ploidy , genetics , gene
S hastry , S ishta V. S., W illiam K. S mith , and D elmer C. C ooper . (U. Wisconsin, Madison.) Chromosome differentiation in several species of Melilotus. Amer. Jour. Bot. 47(8) : 613–621. Illus. 1960.—Two species of the section Eumelilotus ( M. alba and M. officinalis ), 2 of Micromelilotus ( M. messanensis and M. segetalis ), 2 F 1 hybrids ( M. officinalis × M. alba and M. messanensis × M. segetalis ), 2 autotetraploids ( M. alba and M. officinalis ), and 1 allotetraploid ( M. officinalis × M. alba ), were utilized during the course of this investigation. The 4 species and F 1 hybrids have 16 somatic chromosomes and the tetraploids have twice that number (32). The 2 Eumelilotus species are completely isolated because of seed failure after cross pollination. The F 1 hybrid ( M. officinalis × M. alba ), obtained elsewhere by the use of embryo‐culture techniques, was intermediate between the parents in certain morphological characters and was ca. 75% pollenfertile whereas the parents approached complete fertility. No structural differences between the chromosomes were evident at pachytene. Disturbances which led to the reduced fertility occurred at later stages of meiosis. The Micromelilotus species are cross compatible, but the F 1 hybrid ( M. messanensis × M. segetalis ) is highly sterile. Despite chromosome structural differences of various types evident at pachytene, bivalents regularly occur at metaphase I. Irregular distribution of the chromosomes at later stages of meiosis leads to high sterility. Species which readily cross but produce a hybrid of very low fertility are likely to compound chromosomal structural differences, because of abnormalities in meiosis, in contrast with species that are completely incompatible.