A Database for Triticeae and Avena
II. 19. A barley plant with 2n=24 chromosomes.*
An Hang, J. D. Franckowiak and A. B. Schooler, Agronomy Department,
North Dakota State University, Fargo, North Dakota 58105 U.S.A.
* Supported in part by Competitive Research Grant No. 59-2381-0-1-460-0
A barley plant with 2n=24 chromosomes (Fig. 1) was found in the F2 progeny
of the cross Hordeum vulgare L. var 'Ono' (4X)/Elymus mollis
Trin (4X)//'Glenn' 2X. Sister F4 plants to 'Ono'/E. mollis plant
have a range of 2n=27-30 chromosomes associated with typical plant phenotypes.
The F1 plant was obtained via embryo culture and presumably a triploid
plant. It was vigorous; spike and spikelet characteristics were intermediate
between six-rowed and two-rowed barley and selfed seed set was about 5
percent. Compared with the diploid sibs, the plant with 24 chromosomes
was more than 14 days later. Initially, the plant developed only one large
tiller; later additional tillers were produced.
Figures 1-3. Chromosomes of the 2n=24 chromosome
plant. 1) Somatic metaphase chromosomes, 2n=14. 2) Meiotic metaphase I
configuration, 1IV + 3III + 5II + 1I.
3) Meiotic anaphase I separation
Cytological study of chromosome associations at MI showed an array of
configurations, similar to those observed in tetraploid barley (Morrison
and Rajhathy, 1960; Nilan, 1964; and Tsuchiya, 1953). The frequency of
different chromosome associations is summarized in Table 1. No pentavalent
or higher valency configurations were noted.
Table 1. Chromosome associations at MI of the plant
In a hypertriploid plant (2n=22) studied by Singh and Tsuchiya (1975),
the total of multivalents and bivalents were usually equal to seven. In
the plant with 2n=42 chromosomes, the total of multivalents and bivalents
usually found nine or ten (Table 1). The most frequent MI configuration
observed was lIV + 3III + 5II + 1I
Chromosome separations noted at anaphase I were 9-15; 11-13; 10-14;
9-1-14; 11-1-12; 11-2-11. Also one with a bridge without fragment was observed.
The 11-13 AI separation of chromosomes was the most frequent class (Fig.
The 2n=24 plant was self-sterile. Pollen fertility estimated with acetocarmine
stain was very low, about 20 percent. Seed set was about 15 percent when
pollinated with a diploid male. Female fertility is higher than anticipated
if only female gametes with 7 or 14 chromosomes were viable. The progeny
of the 2n=24 plant from crosses to diploid Glenn are being investigated.
Morrison, J. W. and T. Rajhathy. 1960. Chromosome behavior in autotetraploid
cereals and grasses. Chromosoma 11:297-309.
Nilan, R. A. 1964. The cytology and genetics of barley. Monographic
supplement No. 3. Washington State Univ. Press.
Tsuchiya, T. 1953. Fertility of autotetraploids and their hybrids in
barley. I. Meiosis and fertility in some autotetraploids. Seiken Ziho 6:46-52.
Singh, R. J. and T. Tsuchiya. 1975. Hypertriploid plants in barley (Hordeum
vulgare L.). Caryologia 28:89-98.
BGN 12 toc
BGN Main Index