Microsporogenesis in diploid species of Coffea L
In this paper are presented to observations on the microsporogenesis in the diploid (2n=22) species of Coffea: C. eugenioides Moore, C. liberica Hiern., C. kapakata Hirsch. and C. racemosa Lour. These species displayed a regular meiotic behaviour in most pollen mother cells with formation of 11 bivalents. The average of 16 to 17 total chiasmata per cell in metaphase was found. Their distribution among the bivalents varied from cell to cell; a mean of one pair of chromosomes shows three chiasmata, three to four bivalents present two chiasmata, and finally a mean of six to seven pairs only one chiasma. Univalents, unequal chromosome distribution to the polen and laggards, which were seen in some cells, may be consequence of certain irregularities as for instance the lack of pairing of some chromosomes and to assinchronism in the anaphases. It has been found that there are variable but generally low amounts (3.19 to 14.61 percent) of irregular anaphases and also of abnormal tetrads (0.10 to 5.10 percent) and sterile pollen grains (4.07 to 16.40 percent)
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| Format: | biblioteca |
| Published: |
1977
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| Subjects: | COFFEA EUGENIOIDES, COFFEA LIBERICA, COFFEA RACEMOSA, MEIOSIS, POLEN, GENETICA, MICROSPOROGENESIS, NUMERO DE CROMOSOMAS, |
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