BGN 4: Preliminary results on genetic studies of outer glume characters in barley BARLEY GENETICS NEWSLETTER, VOL. 4, II. RESEARCH NOTES
Tsuchiya, pp. 76-78

II.37. Preliminary results on genetic studies of outer glume characters in barley.

T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80521, USA.

Various morphological modifications of the outer glume have been genetically studied and used as linkage markers in studies in barley.

There is a great deal of confusion in the literature regarding these glume characters. The confusion has resulted mainly from: (1) misunderstanding of the character or character description as a result of a lack of pictures or figures in published papers, (2) insufficient literature surveys prior to publication and (3) complicated and inaccurate use of nomenclature and symbolization.

An extensive critical analysis is being conducted to attempt to solve some of the problems in genetics of glume characteristics.

In this article some results so far obtained are briefly reported. Twenty-two varieties and strains have been used in this study (Table 1). The phenotypes of F1 hybrids have been studied.

TABLE 1. Materials and their glume characters.

There is reason to believe that the first three stocks are the same or have the same origin as far as wide glume and very long glume awn are concerned.

All F1 hybrids from crosses of strains within and between the strains in groups I and II showed wide glume character (3.5 mm to 5.0 mm). From these it is obvious that all 12 strains in Group I and II are allelic to each other regarding wide glume character.

The presence or absence and the length of awn on these wide glumes is different in different cross combinations. The genetics of awn expression will be studied in F2 and F3.

The reciprocal hybrids of strains or varieties between group I and III and II and III showed all narrow glume (0.8 mm to 1.1 mm) similar to the parents in group III. The glume awn length varied from 4 mm to 14 mm.

Based on the results obtained from the analysis of Fl phenotypes, it is concluded that:

(l) Wide outer glume in all 12 strains used is controlled by a single recessive gene, probably w, first proposed by Hor (1924). This symbol was later changed to e for elongated outer glume. Very little information is available on Log vs. log genotype in the wide glumed varieties (Helgason, 1964).

(2) All varieties in group III have the gene E which expresses narrow, small glume and is dominant over e for wide outer glume.

(3) As shown in Table 1, there are at least two types of glume awn length, long (Log) and short (log) in E background. Glume awn length, is probably affected by other genes such as Lk in Engleawnless (No. 20 in group III) and br in chromosome 1S (No. 22 in group III).

(4) Robertson, et al. (1955) proposed the following relationships:

From the results mentioned above it is obvious that this proposal is not valid; Ee and Log log control different traits of glume characters. There are at least four genotypes as far as Ee and Log log alleles are concerned:

EE Log Log     Guy Mayle (Neatby, 1926), Montcalm (Helgason, 1964).
EE log log       Canadian Thorpe (Neatby, 1926), Jet (Helgason, 1964).
ee Log Log      G9 (C.I. 6187) (Helgason, 1964).
ee log log        KB5 (Helgason, 1964).

According to Helgason (1964) the elongate homozygote ee is completely epistatic to expression at the Log log locus. More detailed and critical analysis may be necessary to clarify the genetics of glume characters particularly in Montana Wide Glume (No. 7) and G8 (No. 8).

Awnlessness on glumes in four strains (Nos. 9 to 12) in group II is another problem to be studied. Helgason (1964) has proposed a gene for inhibitor of glume awn expression (Ine = Ie) in ee background. Critical analysis is now underway to study this problem.

References:

Helgason, S. B. 1964. Barley Genetics I:181-185.

Hor, E. S. 1924. Genetics 9:151-180.

Neatby, K. W. 1926. Sci. Agr. 7:77-84.

Robertson, D. W. et al. 1955. Agron. J. 47:418-425.
 

The research work reported in the papers No. II.33, II.34 (p. 65-69) and II.37 (p. 76) through II.42 (p. 90) by T. Tsuchiya and associates was partly supported by NSF Research Grant GB 30493 and Colorado State University Experiment Station Project (Hatch 8).

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