BGN 2: New linkage data obtained in 1971 BARLEY GENETICS NEWSLETTER, VOL. 2, II. RESEARCH NOTES
Takahashi et al., pp. 74-76

II.30. New linkage data obtained in 1971.

R. Takahashi, J. Hayashi and I. Moriya. The Ohara Institute for Agricultural Biology, Okayama University, Kurashi 710 Japan.

* Editors note: The symbol mt2 used by the author had been previously assigned. The provisionary symbol, mt,,e was substituted for mt2 in the manuscript.

1. Mottled,,e* in Victorie on chromosome 2.

A spontaneous mutant characterized by the mottled leaves was found in a row of a cultivar, Victorie of Italian origin in our field at Kurashiki, Japan. The mutant is almost similar in appearance to the mutant mottled which was received from Dr. G. W. R. Walker, Edmonton, Canada, and proved to be conditioned by a single recessive gene. Since an allelic test has indicated that these two mutants are controlled by different genes, a gene symbol mt,,e is given to this new mutant.

Linkage of the mutant mt,,e was studied using two crosses with Orange lemma and L.T. 16. The results have revealed that mt,,e is independently inherited of n (chromosome 1), uz (3), K (4), trd and B (5), o (6) and s (7), but linked with v for six-row on chromosome 2. The linkage intensity between mt,,e and v was estimated from the F2 repulsion data to be 14.37 + 4.0196 (%). Number of F2 plants treated is 588. An F3 data will be obtained in the coming spring.

2. Linkage between gs6 for glossy sheath in Kogane Mugi and sk for subjacent hood in Tayeh 13.

A gene symbol gs7 was previously assigned to the glossy sheath in Kogane Mugi (Takahashi and Hayashi 1966), but, according to McProud and Eslick (1971), it is allelic to gs6 in Domen and should be denoted gs6q. The characteristic features of glossy sheath in Kogane Mugi and subjacent hood in Tayeh 13 were described in detail in our previous paper, and the genes for these characters were already shown to be on chromosome 2 by means of trisomic analysis (Takahashi et al. 1953, Takahashi and Hayashi 1966). However, all of our efforts to determine the locations of these two mutant genes have never been rewarded: The gene sk was found to be inherited independently not only of e and v, but also of li and or, which had been known to be located at the distal ends of the long and short arms. For gs6 it has been confirmed also to be independent of v and or.

A further test was made using a cross between Tayeh 13 (sk) and a multiple marker stock An/an-uz-gs6 which was obtained from a Kogane Mugi x An/an-uz cross. The F2 result has indicated that gs6 and sk are located rather closely. The recombination value was estimated to be 9.48 + 4.3707 (%). (Phase repulsion, number of F2 plants treated 512). F3 progenies are now growing in the field.

References:

Takahashi, R., J. Yamamoto, S. Yasuda and Y. Itano. 1953. Inheritance and linkage studies in barley. Ber. Ohara Inst. landw. Forsch. 10:29-52.

Takahashi, R. and J. Hayashi. 1966. Inheritance and linkage studies in barley. Ber. Ohara Inst. landw. Biol. 13:185-198.

3. 'Dusky' mutant from Chikurin on chromosome 7.

Dr. J. Yamashita of the Institute of Radiation Breeding, Japanese Ministry of Agriculture and Forestry, provided us a mutant that may be called 'dusky' which was induced by gamma ray irradiation of a Japanese cultivar, Chikurin-Ibaragi 1. Its main characteristic is that about the time of heading the leaf-blade and sheaths begin to be dehydrated and to turn to dusky color. Many, small dark spots are seen scattered over the surface of these olive-gray colored plant parts. Even after maturity, the heads and stems remain faint green color.

The mode of inheritance and linkage of the mutant character was studied by use of two crosses made between the mutant and marker stocks, Nigrinudum and Xc/xc-o. The F2 results of these crosses have revealed that 'dusky' is conditioned by a single recessive gene, and it is independently inherited of the genes, n and l on chromosome 1, v (2), uz (3), K (4) and o (6). On account of distorted segregation of Bb for black vs. yellow kernel, its relation with dusky character pair could not be determined. On the other hand, excessive parental character combinations were apparent for the character pairs, rachilla hairs (Ss) on chromosome 7 and normal vs. 'dusky' leaf color, suggesting linkage between these two pairs of genes. Since two linkage values, 19.29 and 23.42 (%), were obtained from the two crosses, they were averaged and obtained an estimate, 21.58 + 3.290 (%). The F3 progeny test, now in progress, will yield a more accurate estimate of linkage in near future.

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