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Evaluation of chromosome number stability in two sugarcane varieties^*

Maria Bernadete Silvarolla^I; Margarida L.R. de Aguiar-Perecin^II

^ISeção de Genética, Instituto Agronômico, Caixa Postal 28, 13001-970 Campinas, SP, Brasil
^IIDepartamento de Genética, ESALQ/USP, Caixa Postal 83, 13400-970 Piracicaba, SP, Brasil. Send correspondence to M.L.R.A.-P.

ABSTRACT

During an investigation of the stability of chromosome numbers of plants regenerated in vitro from sugarcane varieties, we developed a technique to obtain clearly intact somatic metaphase cells, showing details of the morphology of the chromosomes and with a low degree of chromosome overlapping. Some root tip pretreatments were tested and the combination of 8-hydroxyquinoline plus cycloheximide and a-bromonaphthalene with cycloheximide produced the best results, respectively for the varieties NA56-79 (2n=114) and Co419 (2n=113). A criterion to evaluate the accuracy of chromosome counts was adopted and the results showed that these varieties have chromosome stability.

Keywords: chromosome; number stability; sugarcane.

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* Part of a thesis presented by M.B.S. to ESALQ/USP in partial fulfillment of the requirements for the Master's degree.