Microsporogenese de Coffea canephora Pierre ex Froehner com número duplicado de cromosomos

Cytological investigation in a tetraploid plant of Coffea canephora with 2n = 44 chromosomes were performed. In every meiosis phase studied, 92.0 per cent of the pollen mother cells were found as 2n = 44 chromosomes. In diakinesis, the chromosomes were found as univalents, bivalents, trivalents and quadrivalents. At first metaphase, only 13.16 per cent were 22 subindex II. The average chromosomic associations were 3.61 subindex I, 15.21 subindex II, 0.71 subindex III, and 1.93 subindex IV. Irregular chromosomic distribution to the poles included 21-23, 20-24 and 19-25, while only 37.65 per cent of the cells exhibited normal segregations of 22 chromosomes to each pole at first anaphase. At second anaphase, seven different types of chromatic distribution were found and only 26.0 per cent of the cells showed regular segregation to the poles. After cytokinesis, triads (1.6 per cent), tetrads (77.0 per cent) and polyads (21.4 per cent) were observed. Pollen viability was 21.0 per cent. Observations made on transversal slices of the fruits showed 43.4 percent normal, 11.0 per cent being of the "peaberry" type and 32.4 per cent of the "flat" normal ones. Fruits without normal seed development were found in a percentage of 56.6, resulting in empty fruit locus

Bibliographic Details

Main Author:	49499 Boaventura, Y.M.S.
Format:	biblioteca
Published:	1990
Subjects:	COFFEA CANEPHORA, MICROSPOROGENESIS, TETRAPLOIDIA, NUMERO DE CROMOSOMAS, MEIOSIS, CITOLOGIA,
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