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- The Cytology of Saccharum spontaneum L. in the Philippines
The Cytology of Saccharum spontaneum L. in the Philippines
Abstract:
A crytological study was made of ten clones of S. spontaneum collected from different parts of the Philippines. The metotic and meiotic behaviors of the chromosomes of the different clones were examined and behaciors of the chromosomes of the different clones were examined compared.
The chromesome number was found to vary from 2n= 56 to 2n = 80.
On the basis of chromesome number, the ten clones may be classified into three groups, namely: Group 1, 2n = 56; Group II, 2n = 72; and Group III, 2n = 80. Since the basic chromosome number is 8, the ten clones of S.spontaneum have 7x, 9x and 10x chromesome number, respectively.
Chronsome mosaics were evident in somatic cells from root tips, while generally normal meiotic behavior was exhibited by the microsporocytes. At the pachytene stage, synapsis of two homologues was observed as well as incomplete pairings, indicating partial homology of some of the chronsomes.
Bivalents and multivalent were observe at diaknesis and metaphase I, Multivalent associations could be due to the partial homology and stickiness of the chromeomes. Multivalent and bivalent associations, although of low frequency, are indications that S. spontaneum is a segmental allopolyploid.
Laggardsa and bridges were the only chromsal aberrations noted during anaphase I and telophase I. These aberrations could be attributed to late disjunction or stickiness of the chromosomes.