Genetics and Cytology of Chromosome Inversions in Soybean Germplasm
- R.G. Palmer *a,
- H. Sunb and
- L.M. Zhaob
One type of chromosome aberration, an inversion, results in the reverse orientation of genes on a chromosome. Inversions are very useful in genetic linkage tests and have been important in the evolution of certain species of animals and plants. In soybean, three accessions (PIs) with a paracentric chromosome inversion were identified. Our objective was to determine if the paracentric inversions identified in PI 597651 and PI 597652 [Glycine max (L.) Merr., cultivated species] and in PI 407l79 (G. soja Siebold & Zucc., wild annual species) were identical. The G. soja inversion was backcrossed into G. max cultivar Hark. The two G. max accessions from China were intercrossed, and based on pollen staining of F1 and F2 plants, were considered identical in chromosome structure. However, the G. soja accession had a chromosome structure different from the two G. max accessions. Meiotic studies confirmed the presence of the paracentric inversions. Crosses of PI 597651 with either cultivar Hark or Hark homozygous inversion gave F1 plants with two to three times as many meiotic cells with chromosome bridges as cells with laggards and fragments. However, crosses of PI 567652 with either cultivar Hark or Hark homozygous inversion gave F1 plants with about equal numbers of meiotic cells with bridges as cells with laggards and fragments. Therefore, cryptic structural differences between these two Chinese accessions might influence chromosome pairing, crossing over, and segregation. This might explain the different meiotic behaviors in crosses of the two Chinese accessions with Hark and Hark homozygous inversion.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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