Articles
CYTOLOGICAL PECULIARITIES IN TOMATO (SOLANUM LYCOPERSICUM) NUCLEAR MALE STERILITY
Article number
830_43
Pages
305 – 312
Language
English
Abstract
A cytological investigation for identification of the meiotic stages and mechanism of male sterility expression in nuclear male sterile tomato line No. 6944aa (msms1035) was performed in Maritsa Vegetable Crops Research Institute, Plovdiv, Bulgaria.
The male sterile genotypes from second backcross progenies (BC1P2 and BC3P2) of the hybrid between line No. 6944aa and line No. 1 were cytologically characterized.
The purpose was – to study the heritage and stability of the male sterility in creation of new sterile tomato line.
The meiotic analysis in the pollen mother cells of sterile genotypes from line No. 6944aa revealed, that 12 bivalents were formed during the diakinesis and metaphase one in 74.1% of the cells.
In parallel with bivalents 1 to 2 quadrivalents were observed in 15.8% of PMC and in case of desynapsis and early bivalent and quadrivalent separation 2 to 22 univalents in 10.1% of the cells were established.
The normal pairing of homologous chromosomes of sterile msms 1035 plants from the different backcross progenies was described in 73.6 and 75.9% of PMC. The similar formation of multivalents and univalets, as in the mother sterile plants, was observed in backcross msms 1035 plants.
The chromosomes have been distributed visually regular toward the spindle poles during the anaphase one both in the mother and in the backcross sterile genotypes in about 91–92% of the meiocytes.
The cells lethality took place after second telophase, as the expression of the gene responsible for cytokinesis was blocked and we did not observe tetrad stage and microspore formation in msms 1035 plants.
The cytological mechanism of nuclear male sterility in tomato, determined by gene ms 1035 probably is the presence of reciprocal, symmetric heterozygous translocations, as the disruptions of chromosomes destroyed expression of the genes which defined normal initiation, running and termination of the some meiotic stages.
As a result of meiotic abnormalities chromosomes and gene unbalanced nuclei were formed, which reflected in pollen mother cell lethality.
The male sterile genotypes from second backcross progenies (BC1P2 and BC3P2) of the hybrid between line No. 6944aa and line No. 1 were cytologically characterized.
The purpose was – to study the heritage and stability of the male sterility in creation of new sterile tomato line.
The meiotic analysis in the pollen mother cells of sterile genotypes from line No. 6944aa revealed, that 12 bivalents were formed during the diakinesis and metaphase one in 74.1% of the cells.
In parallel with bivalents 1 to 2 quadrivalents were observed in 15.8% of PMC and in case of desynapsis and early bivalent and quadrivalent separation 2 to 22 univalents in 10.1% of the cells were established.
The normal pairing of homologous chromosomes of sterile msms 1035 plants from the different backcross progenies was described in 73.6 and 75.9% of PMC. The similar formation of multivalents and univalets, as in the mother sterile plants, was observed in backcross msms 1035 plants.
The chromosomes have been distributed visually regular toward the spindle poles during the anaphase one both in the mother and in the backcross sterile genotypes in about 91–92% of the meiocytes.
The cells lethality took place after second telophase, as the expression of the gene responsible for cytokinesis was blocked and we did not observe tetrad stage and microspore formation in msms 1035 plants.
The cytological mechanism of nuclear male sterility in tomato, determined by gene ms 1035 probably is the presence of reciprocal, symmetric heterozygous translocations, as the disruptions of chromosomes destroyed expression of the genes which defined normal initiation, running and termination of the some meiotic stages.
As a result of meiotic abnormalities chromosomes and gene unbalanced nuclei were formed, which reflected in pollen mother cell lethality.
Publication
Authors
V. Nikolova, D. Ganeva, Y. Stefanova
Keywords
Solanum lycopersicum, male sterile genotype, meiosis, translocation, degeneration of meiocytes
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