The cytology of the trigenomic hybrid

The trigenomic hybrid of Zea mays, Zea diploperennis and Tripsacum dactyloides has been studied in detail. The plant is weakly perennial and maintained by means of cuttings. Samples from this plant were analysed in detail at all stages of meiosis. Maize and diploperennis showed normal pairing at pachytene, as a result, 10" of maize and diploperennis, and 18' of Tripsacum were seen in the triploid in a great percentage of cells. At diakinesis the following associations of chromosomes were seen:

10" (maize + diploperennis) + 18' (Tripsacum) - 75% of cells.

9" + 2' (maize + diploperennis) + 18' (Tripsacum) - 10%, of cells.

7" + 6' (maize + diploperennis) + 18' (Tripsacum) - 10% of cells.

In the remaining 5% of cells various combinations as 1) 5" perhaps all maize, or all diploperennis, + 28'; 2) 5" + 10' + 18'; 3) 6" + 1"' + 23'. Occasionally the 18' of Tripsacum showed non-homologous pairing within themselves; as a result there were about 12" + 14'. There were cells that showed more than 38 chromosomes in this triploid material. This could be due to the presence of B chromosomes in the Tripsacum background.

Chandra V. Pasupuleti and Walton C. Galinat

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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