Genetica

, Volume 39, Issue 1, pp 360–370 | Cite as

Inter- and intra-genomal chromosome pairing in an interspecific hybrid and its bearing on basic chromosome number inPennisetum

  • Prem P. Jauhar
Article

Abstract

Meiosis in the interspecific hybrid betweenPennisetum typhoides (2n=14; genomeAA) andP. purpureum (2n=28; genomesA′A′BB) has been studied with particular reference to allosyndetic and autosyndetic pairing of chromosomes. Although up to nine bivalents occurred in the hybrid, never more than five were observed to be (heteromorphic)AA′ bivalents (range 1–5). It has been concluded thatA andA′ genomes are onlypartially homologous. It has further been inferred that the two genomes are evolutionarily related and could have arisen from a common progenitor withx=5 chromosomes or from related species withx=5 chromosomes.

Autosyndetic pairing of chromosomes within thetyphoides complement (A genome) and within theA′ genome ofpurpureum have been reported here for the first time. Intra-haploid pairing to a probable maximum of two bivalents within each of the three genomes of the hybrid, viz.,A, A′ andB, further suggestsx=5 as the phyletically basic number in the genusPennisetum. It has been inferred thatx=7 is a secondarily basic number, having been derived fromx=5. The occurrence of a species withn=5 inPennisetum, viz.,P. ramosum, substantiates this view. Further support in favour of this conclusion comes from the secondary association of bivalents in dipoidP. typhoides. Thus, the apparently diploid species,Pennisetum typhoides with2n=14 chromosomes is considered to be a “secondary diploid” having a secondarily balanced number ofx=7.

On the basis of the results obtained by the author is conjunction with the available evidence from the literature, it is suggested thatx=5 may be the original basic number for the entire grass family and seven, the most preponderant number in it, and other higher numbers derived from it subsequently during the course of evolution.

Keywords

Related Species Chromosome Number Chromosome Pairing Interspecific Hybrid Diploid Species 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Burton, G. W. (1944). Hybrids between Napier grass and Cattail Millet.Jour. Hered. 35: 227–232.Google Scholar
  2. Celarier, R. P. (1956). Additional evidence for five as the basic chromosome number of theAndropogoneae.Rhodora 58: 135–143.Google Scholar
  3. Flovik, K. (1938). Cytological studies of arctic grasses.Hereditas 24: 265–376.Google Scholar
  4. Hunter, A. W. S. (1934). A karyosystematic investigation in theGramineae.Canad. Jour. Res., C.11: 213–241.Google Scholar
  5. Jauhar, P. P. (1963). Cytotaxonomic investigations in the genusPanicum L. Ph. D. Thesis, Post Graduate School, I.A.R.I., New Delhi, India.Google Scholar
  6. Jauhar, P. P. & A. B. Joshi (1966). Cytological studies in some species ofPanicum.Cytologia 31: 153–159.Google Scholar
  7. Kempanna, C. & R. Riley (1964). Secondary association between genetically equivalent bivalents.Heredity 19: 289–299.Google Scholar
  8. Kimber, G. & R. Riley (1963). Haploid angiosperms.Bot. Rev. 29: 480–531.Google Scholar
  9. Krishnaswamy, N. & V. S. Raman (1951). Cytogenetical studies in the interspecific hybrid ofPennisetum typhoides Stapf etHubb. xP. purpureum Schum.Proc. I Sci. Workers Conf. Madras Agric. Dept. pp. 43–71, Govt. Press, Madras, India.Google Scholar
  10. Krishnaswamy, N. & V. S. Raman (1953). Studies on the interspecific hybrid ofPennisetum typhoides Stapf etHubb. xP. purpureum Schum. II. The cytogenetics of two 22-chromosomed F2 plants.Cytologia 18: 305–321.Google Scholar
  11. Magoon, M. L. & K. R. Khanna (1963). Haploids.Caryologia 16: 191–235.Google Scholar
  12. Myers, W. M. (1947). Cytology and genetics of forage grasses.Bot. Rev. 13: 318–421.Google Scholar
  13. Nandi, H. K. (1936). The chromosome homology, secondary association and origin of cultivated rice.Jour. Genet. 33: 315–336.Google Scholar
  14. Naravan, K. N. (1954). Meiosis in the pollen mother cells ofPennisetum ramosum (2n=10).Curr. Sci. 23: 407–408.Google Scholar
  15. Raman, V. S. (1964). Progress of cytogenetic research in Madras State. In: Advances in agricultural Sciences pp. 122–143,The Madras Agric, Jour., Coimbatore, India.Google Scholar
  16. Riley, R. (1960). The secondary pairing of bivalents with genetically similar chromosomes.Nature 185: 751–752.Google Scholar
  17. Riley, R. (1966). Genetics in the regulation of meiotic chromosome behaviour.Sci. Prog. 54: 193–207.PubMedGoogle Scholar
  18. Riley, R. & C. N. Law (1965). Genetic variation in chromosome pairing.Adv. Genet. 13: 57–114.Google Scholar
  19. Swaminathan, M. S. & J. Nath (1956). Two new basic chromosome numbers in the genusPennisetum.Nature 178: 1241–1242.Google Scholar
  20. Wanscher, J. H. (1934). The basic chromosome number of the higher plants.New Phytol. 33: 101–126.Google Scholar

Copyright information

© Martinus Nijhoff 1968

Authors and Affiliations

  • Prem P. Jauhar
    • 1
  1. 1.Division of GeneticsIndian Agricultural Research InstituteNew DelhiIndia

Personalised recommendations