A Database for Triticeae and Avena
II.46. Another case of paracentric inversion in a genetic stock,
Engleawnless, for Lk of barley.
T. Tsuchiya and R. J. Singh. Department of Agronomy, Colorado State
University, Fort Collins, Colorado 80521, U.S.A.
Supported in part by NSF Research Grant GB 30493 and Colorado State
University Experiment Station Project (Hatch 8).
It has been known for quite some time that there is no recombination
between Vv alleles and Lklk alleles on chromosome 2 when
the genetic stock Engleawnless for a dominant short awn gene Lk
and two-rowed gene V was used in crosses with a six-rowed, long
awn stock (lk v) (Engledow, 1924; Wiebe, 1972). Wiebe (1972) suggested
the existence of an inversion to explain this phenomenon.
Kuckuck (1930), however, reported the crossover value of 9.6% between
Vv locus and Lklk locus, though allelic relationship of the
stocks for awnless used by Engledow and those used by Kuckuck has not been
The present writer has been conducting a critical genetic analysis of
glume characters of barley including the effects of short awn and awnless
genes on the expression of glume awn, because of rather confusing results
so far reported for glume characters (Robertson et al. 1955; Helgason,
1964; Robertson, 1971). During this experiment, F1 hybrids from various
cross combinations, including Engleawnless as one of the parents, were
grown in the greenhouse.
The finding of a paracentric inversion in a genetic stock for white
streak (wst 3) (Tsuchiya, 1972) has stimulated the present writer
to study the cytological behavior of F1 hybrids between Engleawnless and
other genetic stocks. Meiosls of an F1 hybrid between Engleawnless and
a wide outer glume mutant (Stock Ab 1457) was studied.
A bridge-fragment configuration was found at anaphase I of meiosis of
the above-mentioned hybrid. The frequency of sporocytes with bridge-fragment
was very low.
From these results it is concluded that Engleawnless has a paracentric
inversion in one of its chromosome pairs. At present, there is no evidence
to prove that the paracentric inversion is in chromosome 2. A critical
cytogenetic analysis is being conducted by means of trisomic analysis to
associate this paracentric inversion with the particular chromosome.
The present writer suggests barley workers not to use Engleawnless for
genetic and linkage studies until this problem is solved.
Engledow, F. L. 1924. Inheritance in barley. III. The awn and lateral
floret: fluctuation: a linkage: multiple allelomorphs. Jour. Genet. 14:49-87.
Helgason, S. B. 1964. Inheritance of glume characteristics in some barley
crosses. Barley Genetics I (Proc. Ist Intern. Barley Genet. Symp.):181-185.
Kuckuck, von H. 1930. Versuche einer vollaufigen Chromosomentopographie
bei Gerste. Zuchter 3:68-72.
Robertson, D. W. 1971. Recent information of linkage and chromosome
mapping. Barley Genetics II (Proc. IInd Intern. Barley Genet. Symp.):220-242.
Robertson, D. W., G. A. Wiebe, R. G. Shands. A Summary of Linkage Studies
in Barley: Supplement II, 1947-1953. Agron. Jour. 47: 418-425.
Tsuchiya, T. 1972. A case of paracentric inversion affecting genetic
behavior of a white streak gene. BGN 2:104-105.
Wiebe, G. A. 1972. Tight linkage of the awnless gene in Engleawnless
with the Vv locus. BGN 2:108.
BGN 2 toc
BGN Main Index