Cytogenetic evaluation of anther culture-derived Nicotiana tabacum L.: flue-cured tobacco
1987
Jacinto, J.J. | Mercado, M.S. | Javier, E.L. (Philippine Tobacco Research and Training Center, Batac, Ilocos Norte (Philippines))
The study was conducted to determine the chromosome number and behavior of 45 and 37 anther culture-derived plants of NC 95 and of the F1 of NC 95 x NCBY, respectively. All anther culture-derived plants except 2 had 24 chromosomes, indicating their haploid status. The plants had 23 chromosomes. There was a general absence of regular pairing at metaphase 1. However, chromosome associations, where 2 or more univalents were joined by thick or thin chromatin, were observed. Non-aligned chromosomes at metaphase 1 and 2 were found. Laggards and bridges were also found at anaphase 1 and 2. Several cells at telophase 1 and 2 showed logging chromosomes. There was irregular distribution of chromosomes at anaphase 1, and this was expected to persist until telophase 2. Analysis of dyad orientation revealed 4 types: "N", "L", "S" and "T". The "S" type was the most frequent in all haploids. The "L" and "T" types were the least frequent among haploids of NC 95 and of the F1 of NC 95 x NCBY, respectively. Four types of nuclei orientation were observed at telophase 2. However, there was no apparent trend in the frequencies of types among haploids from a common anther source.
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