GrainGenes
A Database for Triticeae and Avena
Tsuchiya, pp. 82-85
II.40. Further results of allelism testing in barley.
T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80521, USA.
This is a continuation of allelism testing of various mutant types in barley. Included are the following types of mutations:
1. Third outer glume (trd)
2. Elongated (wide) outer glume (e)
3. Long basal rachis internode (lb)
4. Chlorina
5. Curly
1. Third outer glume (trd)
Spontaneous mutants for third outer glume have been reported by several authors (BGN, 1:147). A similar mutant (Mut 1969/61) in the variety Proctor was reported to be allelic to trd (Hauser and Fischbeck, 1972, BGN 2:28-29). A Swedish mutant designated as bracteatum (bra-c1) was tested for its allelic relation with the stock for trd. The results are shown in Table 1.
Table 1 F1 analysis of trd and bra-c1.
The experimental results show that bra-c1 is allelic to trd. Thus, all trd mutants so far studied, spontaneous or artificially induced, are allelic and occur in the same locus in the long arm of chromosome 5.
2. Elongated (wide) glume (awn).
There is considerable confusion in the nomenclature and gene symbolization for glume characters in barley (Robertson et al. 1955; Tsuchiya, 1974a). The one rather widely used mutant character is so-called "elongate outer glume awn" (e). The present author's extensive allelism testing using many stocks showed that the "wide glume" character in all stocks tested is allelic and recessive to the gene (E) for "normal" or narrow (and small) glume character. The presence or absence of "glume awn" is controlled by other genetic factor(s) (Tsuchiya, 1974). Helgason (1964) has suggested a dominant inhibitor (Ine) to prevent the development of "elongated glume awn".
The standard genetic stock for the e gene has been Triple Bearded Club Mariout (CSU, B3-5) which has wide, long glume (4 mm wide x 12 mm long) and long glume awn (92 mm long). Similar mutants to Triple Bearded Club Mariout have been obtained in various institutions by mutagen treatments, and named as "macrolepis" with the gene symbol of lep-e (Gustafson et al. 1969). According to Stubbe (1959), several radiation-induced macrolepis mutants (lep-e) were proved to be allelic to a spontaneous mutant (most likely e) (Nötzel, 1952). Hauser and Fischbeck (1972) also reported that the gene for elongate glume mutant (Mut 3447/64) in the variety Proctor was allelic to e. The present author tested a Swedish mutant, lep-e, with the standard stock for e and found that they are allelic. This result confirmed the similar experiment by Nybom (1954) on the same mutant.
All these results indicate that wide glume mutants occur repeatedly at the same locus in the short arm of chromosome 2.
3. Long basal rachis internode (lb).
The long basal rachis internode has been designated as C-type basal rachis internode by Aberg and Wiebe (1946). The similar character was studied by several workers, and a recessive gene, lb, of Wisconsin 38 (Barbless) was located in chromosome 7 (Hehn, 1948; Smith, 1951; Robertson et al. 1955). Various other varieties and some new mutants also showed long basal rachis internode similar to that for lb.
Allelism tests have shown that the following varieties and mutants have
the gene allelic to lb of Wisconsin 38 as shown in Table 2.
1. Long rachis internode, C.I. 6164, CSU B12-4
2. Comfort II for f8, BGS 0005
3. Bracteatum for rac-a2
4. Bracteatum for rac-b1
Table 2. Phenotype of F1 hybrids between various lb-type mutant strains.
4. Chlorina seedling
The results of allelism testing of chlorina mutants have been reported previously by the present author and his associates (Tsuchiya, 1972, Tsuchiya, et al. 1973). In this note the supplemental data on the allelism testing for f3, Ko-C chlorina and other chlorina mutants are reported.
f3: This mutant was crossed with f4, f6, f7, and f9 and all F1 plants were green (Tsuchiya, et al. 1973). In this experiment, f3 was crossed with fc, f, f4, f5, f8, f9, lg5 and Ko-C chlorina. All F1 hybrids were green. These results indicate that f3 is not allelic to any of 10 designated genes in f series (fc and f - f9), nor to lg5 and one new mutant, Ko-C chlorina. The stock for f3 was also crossed with green plant of Shin Ebisu 16(S.E. 16) and Trebi chlorina (T1-27) which was proved to be maternal inheritance. All F1 hybrids were green. Thus f3 for chlorina is not maternally inherited.
Ko-C Chlorina: This is a radiation-induced chlorina mutant in the two-rowed variety Ko-C (Tsuchiya, unpublished). This mutant was crossed with all 1O stocks of the designated f series (fc and f - f9) and one light green mutant, lg = lg8. All F1 hybrids were green indicating that: (1) Ko-C chlorina is not allelic to 11 tested genes for chlorina (or light green). (2) Ko-C chlorina is not maternally inherited.
5. Curly mutants.
Curly leaf mutants (curly 2, cu2) were reported by Takahashi and Hayashi (1966). Similar mutants have been obtained by mutagen treatments and named as "dwarf", "deformed plant, Bikini", (Gustafsson et al. 1969), and "Spiral neck" (KM118, Tsuchiya, unpublished). The characteristics of these mutants are reported by Tsuchiya (1974b, BGN 4:88). Allelic relationships were studied in the analysis of phenotypes of F1 hybrids from various crosses (Table 3).
Crossing was extremely difficult in many cases because of extremely deformed florets of these mutants and some of the crossed seeds did not germinate. Even though the number of F1 plants was very small their hybrid nature was confirmed by other genetic factors. The stock for cu2 is also homozygous for another recessive trait, uzu or semi-brachytic (uz), while all other stocks have its dominant allele Uz. The F1 hybrids of cu2 x Deformed Bikini showed normal or Uzu (Uz) type which is the evidence that the ''F1'' was real hybrid.
In the cross, Dwarf 2 x cu2 the female was Uz type. Approximately 3:1 segregation of normal (Uz) vs. uzu (uz) was observed in F2, indicating that the ''F1'' plants were true hybrids.
These results indicate that the genes of the two different Swedish mutant types, "dwarf 2" and "deformed, Bikini" are allelic to cu2.
From the detailed morphological studies including the root character, it is obvious that curly is an adequate name for this type of mutant. Thus, two names, "dwarf" and "deformed, Bikini" will not be used to designate curly mutants.
The gene for the mutant "spiral neck" of KM118 was proved to be not allelic to cu2. The name "spiral neck" will be changed to curly, even though the mutant character is really spiral neck which was proved by taking movie pictures successively during its development (Documents of Asahi Brewery Company, Tokyo).
References:
Aberg, E. and G. A. Wiebe. 1946. USDA Tech. Bull. 907, 190 pp.
Gustafsson, A., A. Hagberg, U. Lundqvist and G. Persson. 1969. Hereditas 62:409-414.
Hauser, H. and G. Fischbeck. 1972. BGN 2:28-29.
Hehn, E. R. 1948. Iowa State Coll. Jour. Sci. 23:39-40 (Abst).
Helgason, S. B. 1964. Barley Genetics I (Proc. Ist. Intern. Barley Genet. Symp.):181-185.
Nötzel, H. 1952. Kuhn-Archiv. 66:72-132.
Nybom, N. 1954. Acta Agric. Scand. 4:430-456.
Robertson, D. W., G. A. Wiebe, and R. G. Shands. 1955. Agron. J. 47:418-425.
Smith, L. 1951. Bot. Review 17:1-51, 133-202, 285-355.
Stubbe, H. 1959. Cold Spring Harbor Symp. Quant. Biol. 26:31-40.
Takahashi, R. and J. Hayashi. 1966. Ber. Ohara Inst. landw. Biol. 13:185-198.
Tsuchiya, T. 1972. BGN 2:80-87.
Tsuchiya T. 1974a. BGN 4:76-78.
Tsuchiya, T. 1974b. BGN 4:88-90.
Tsuchiya, T., Debra A. Jensen and T. E. Haus. 1973. BGN 3:71-72.