A Database for Triticeae and Avena
II.41. New karyotype in a genetic stock, Utah T3, for purple lemma
and pericarp (Re 2).
T. Tsuchiya and Jennifer Menke. Department of Agronomy, Colorado State
University, Fort Collins, Colorado 80521, U.S.A.
*Reports II.33. (p.80) through II.42. (p.108) by T. Tsuchiya and co-workers
are based on the results of researches supported by NSF Research Grants
GB4482X and GB30493 and Colorado State University Experiment Station Project
During the study of F1 hybrids between the telotrisomic for Triplo 2L
and the genetic stock for purple lemma and pericarp (Re 2) in Utah
T3, there was found a strange karyotype. Detailed karyotype analysis of
both parents of the hybrid revealed that the Re 2 stock was homozygous
for an abnormal chromosome condition.
In root tip mitosis of the Re 2 stock a normal chromosome 6 was
not found. Instead a pair of large three-segmented chromosomes was found.
In the diploid F1 hybrids between SE 16 and the Re 2 stock there
was found a normal chromosome 6 and a three-segmented chromosome. Careful
comparison of normal chromosome 6 and the abnormal chromosome revealed
that the abnormal chromosome consisted of a long and short arm of chromosome
6 and an abnormally large satellite, as shown in Figure 1.
Fig. 1. The somatic chromosomes of diploid hybrid
between Shin Ebisu 16 and Utah T3. The photo shows the heterozygous condition
of chromosome 6; 6 indicates the normal chromosome 6 and 6t
the translocated chromosome 6.
Based on these findings it is assumed that a translocation has occurred
between the satellite of chromosome 6 and one arm of one of the four longest
non-satellited chromosomes. F1 hybrids between Utah T3 and Shin Ebisu 16
showed a ring-of-four and five bivalents at diakinesis and metaphase I
of meiosis. The quadrivalent was associated with nucleolus at diakinesis.
Pollen fertility of F1 diploid hybrids between Shin Ebisu 16 and Re
2 stock was 71.1%. An attempt is being made to establish an Re 2
stock free from this chromosomal aberration.
This finding of spontaneous occurrence of reciprocal translocation in
a genetic stock and the finding of possible case of radiation-induced paracentric
inversion in the genetic stock for wst 3 in variety Akashinriki
(Tsuchiya, 1972, BGN 2:lO4-lO5) suggests that there may be more cases of
chromosomal abnormalities in genetic stocks. Actually, spontaneous inversions
have been detected in the variety OAC 21 and some other varieties (Powell
and Nilan, 1968). Radiation-induced chromosomal aberrations associated
with gene mutations have also been reported; translocations associated
with erectoides mutations (Hagberg, 1960), paracentric inversions
associated with gemetic sterility (Holm, 1960) and a translocation associated
with a male mutant (Tsuchiya, 1969, 1972).
From these findings, the following suggestions are made for barley geneticists:
(1) The fertility (pollen fertility and seed sets) of F1 hybrids should
be studied in all crosses.
(2) If semisterility is found in F1, then meiosis of F1 hybrids should
be critically studied.
(3) Karyotype study of both parental materials are also recommended
for possible finding of detectable translocation shown in the case of genetic
stock of Re 2 for purple lemma and pericarp, if F1 hybrid showed
Hagberg, A. 1960. Genet. Agr. 12:319-336.
Holm, G. Hereditas 46:274-278.
Powell, J. B, and R. A. Nilan. 1968. Crop Sci.
Tsuchiya, T. 1969. Induced mutations in Plants:573-590.
Tsuchiya, T, 1972, BGN 2:104-105.
Tsuchiya, T. 1972. BGN 2:107-108.
BGN 2 toc
BGN Main Index