Chromosomal Biotypes of Carica papaya Linn
25 Dec 1971-Cytologia (Japan Mendel Society, International Society of Cytology)-Vol. 36, Iss: 4, pp 555-562
TL;DR: Slight structural difference in chromosomes of different varieties of Carica papaya is noticed, which proves the role of structural alteration of chromosomes on the evolution of the forms.
Abstract: Five horticultural forms of Carica papaya growing in India have been studied. Karyotypes of them represent homogeneity. Slight structural difference in chromosomes of different varieties is noticed, which proves the role of structural alteration of chromosomes on the evolution of the forms. No heteromorphic pair, or unpaired chromosome or any chromatin body, suggesting chromosomal basis of sex difference in the species, could be recognized.
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10 Dec 2010
TL;DR: In this paper, the authors present a survey of eudicots: sapindales, cucurbitales, myrtaceae, and myrithaceae. And they propose a new genus named myrtium.
Abstract: Perp. punya vol. X. Flowering plant, eudicots : sapindales, cucurbitales, myrtaceae. Perp.punya: 1eks.
2,989 citations
TL;DR: Evidences suggest that the change from bisexuality to unisexuality and homomorphicity to heteromorphicity in chromosomes had been a short step in evolution possibly occurring in the recent past.
Abstract: The review deals with the previous and present data on sexchromosomal mechanisms in the plant system ranging from Bryophytes to Angiosperms. Despite widespread unisexuality, only a few species have well defined heteromorphic chromosomes, heterogamety being present either on the male or on the female side. Reversion of sex through chemical treatment in unisexual species with homomorphic chromosomes indicates a delicate balance between sex determining genes and physiological set up in such species.
In heteromorphic types, in majority of cases, Y is generally longer than X and the male tendency of Y is stronger than the female tendency of X. Even though heterochromaticity is associated, the amount of DNA may or not differ in two sexes. Sex chromosomes may often be nucleolar. With the gradual polyploidization or aneuploidy, there is often changeing sexuality indicating distinct sex-chromosomeautosomal balance for sex determination. Evidences suggest that the change from bisexuality to unisexuality and homomorphicity to heteromorphicity in chromosomes had been a short step in evolution possibly occurring in the recent past. The potential, of banding technique and X-ray fragmentation, in locating specific sex determining segments, has been indicated.
30 citations
01 Jan 1980
TL;DR: This monograph is presented in an effort to summarize previously published information and to offer new observations on the structure of one crop, the papaya.
Abstract: Anatomical and morphological studies of tropical crop plants are widely scattered in journals and reference books. This literature is all too often inaccessible to students and researchers in the developing countries of the tropics. In addition, the structure of many crops has never been carefully studied. These factors present a significant constraint on the teaching of and research in tropical agriculture, since all aspects of agriculture are based ultimately on a firm botanical understanding of the crop and especially its plant structure and function. Therefore, this monograph is presented in an effort to summarize previously published information and to offer new observations on the structure of one crop, the papaya. The format of the present monograph will serve as a basis for what is hoped will be a forthcoming series dealing with different tropical crops. The morphology, anatomy, and cytology of the different vegetative and reproductive parts of the plant are described in detail. The terminology used can be found in an introductory text of plant anatomy (for example Esau, 1977). The author welcomes suggestions or comments that could improve the usefulness of such a reference and could be incorporated in future monographs.
28 citations
Additional excerpts
...Chromosome lengths may vary with variety (Datta, 1971)....
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TL;DR: The objective of this study was to determine the karyotype of three Caricaceae species, the cultivated form (C. papaya) and two wild species (V. monoica and V. cundinarmacensis), and if there are sexual chromosomes in C. papaye, they are probably homomorphic.
Abstract: Papaya (Carica papaya L.) is the most important species of Caricaceae family. All Caricaceae species are classifed as diploids (2n=2x=18 chromosomes) and dioecious, except for C. papaya, V. monoica...
24 citations
Cites methods from "Chromosomal Biotypes of Carica papa..."
...MPixel Qcolor3C digital camera connected to the Olympus BX60 optical microscope. They were analyzed using the Image-Pro Plus Software (5.1 version, Media Cybenertics). The chromosomes were measured using the MicroMeasure 3.3 software (reeveS and tear 2000). The parameters analyzed were: absolute chromosome size (μm), long and short arms length, arm ratio (r = long arm/short arm), total haploid complement (THC = sum of the absolute length of the metaphasic chromosomes), and the centromeric index (CI = (short arm length/total length) x 100). The absolute size and the arm ratio were observed to determine the homologous pairs. The chromosomes were classified according to guerra (1986) who considered the arm ratio (levan et al....
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TL;DR: FISH of rDNA probes is reported on to create several karyological markers that enable chromosomes to be distinguished and to produce information about the genetic relationships among Caricaceae species.
Abstract: Papaya (Carica papaya L.) is cultivated widely as a fruit crop in the tropics. Related species as Vasconcellea cundinamarcensis and V. goudotiana are prospective sources of desirable genes. The requisite germplasm introgression will be facilitated by a better understanding of their cytogenetic relationships to papaya, but the chromosomes of Caricaceae species are very small and similar so conventional karyotyping is difficult and of limited utility. Here, we report on fluorescence in situ hybridization (FISH) of rDNA probes to create several karyological markers that enable chromosomes to be distinguished and to produce information about the genetic relationships among Caricaceae species. Based on the number and the position of rDNA sites, V. cundinamarcensis and V. goudotiana were the closest species while C. papaya was isolated from them. Both Vasconcellea species showed only one pair of 5S site whereas three pairs were found in C. papaya. On the other hand, one 18S site was observed in papaya,...
14 citations
Cites background from "Chromosomal Biotypes of Carica papa..."
...At the genomic level, it is known that papaya has just 18 chromosomes (n=9), all of which are very short, between 1.0 and 4.25µm at mitotic metaphase (datta 1971)....
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...Previous cytological studies in papaya showed that chromosomes do not differ significantly in length or arm ratio and thus cannot be distinguished morphologically (datta 1971)....
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References
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TL;DR: The action of different prefixing agents including water and a dilute CaCl2 solution on plants with high chromosome number showed that all the solutions tried exhibited marked effect on the physical state of the plasma.
Abstract: The action of different prefixing agents including water and a dilute CaCl2 solution on plants with high chromosome number showed that all the solutions tried exhibited marked effect on the physical state of the plasma. Also the plasmatic constitution of the pretreated tissue differed from the appearance of one fixed directly in dye-acid mixture for a few seconds without any pre-treatment. For the clarification of the karyotypes, the best results have been obtained with paradichlorobenzene. It was used as a prefixing agent with a short schedule for temporary smears of difficult materials, particularly those with high chromosome number. The method comprised treatment of the root tips in a saturated aqueous solution of the chemical for 3 hours at 12-16°C., followed by 4-5 seconds heating just to boiling in orcein-hydrochloric acid mixture, then smearing in 1% aceto-orcein solution.
64 citations
TL;DR: The study of the chromosomes of palms has always been considered very difficult, as is clearly evidenced by the lack of data on a large number of genera.
Abstract: THE study of the chromosomes of palms has always been considered very difficult, as is clearly evidenced by the lack of data on a large number of genera1. Even where the number of chromosomes has been recorded, the details of the structure are unknown.
42 citations