| Variation and geographical distribution of esterase
zymograms in Aegilops squarrosa1) Yasuo NAKAI Laboratory of Genetics, Facutly of Agriculture, Kyoto University, Kyoto, 606. Introduction The hypothesis that Ae. squarrosa is the D genome donor to common wheat has been widely accepted. However, many differences in morphorogical and physiological characteristics are found in Ae. squarrosa (KIHARA and TANAKA 1958). Johnson (1972) showed that albumin bands of the common wheat have homology with those of Ae. squarrosa. As to the esterase isozymes, three types of the zymogram were found in Ae. squarrosa. Among those, only one type has the homologous bands with that of present-day common wheat, the two rest types having non-homologous bands. In the present paper, the variation of esterase isozymes was investigated, and its genetic basis was also analyzed. Materials and Methods In total 136 strains of Ae. squarrosa were used in this investigation. The large number of strains were collected by the Kyoto University Scientific Expedition to the Karakoram and Hindukush (abrebiated as KUSE) in 1955, the Botanical Expedition to Caucasus (BEC) in 1966 and the Botanical Expedition to the Northern Highlands of Mesopotamia (BEM) in 1970. Electrophoresis of esterase isozymes was performed using the ordinary gel isoelectric-focusing method (NAKAI 1973). About 40 mg of soaked seeds of each strain were homogenized in 0.5 ml of potassium phosphate buffer (0.05 M, pH 7.0), and the homogenate was centrifuged at 20,000 x g for 15 min. The supernatant was placed on polyacrylamide gel containing a carrier ampholite with a pH range of 6.0 to 8.0. The electrophoresis was carried out at 200 volts and was run for 3 hours. After electrophoresis, gels were stained with 0.1% Fast Blue RR Salt and 0.01% alpha-naphtyl acetate (w/v) in the phosphate buffer (0.07M, pH 7.0) for 10-20 minutes. Results and Discussion 1) Variation on the esterase zymogram In Ae. squarrosa, three zymograms were found which were designated as type 1, type 2 and type 3, respectively (Fig. 1). Type 1 had three major bands, 3E, 5E and 6E (Fig. 1-a). Type 2 had one extra major band, 8E-B (Fig. 1-b). Type 3 differed greatly from types 1 and 2, by having two major bands, 8'E and 10E, and six minor bands, 1E, 3E, 4E, 5E, 6E and 6'E (Fig. 1-c). Type 1was found only a single strain of var. strangulata, and type 2 in var, typica, var. meyeri and var. strangulata. All varieties of Ae. squarrosa contained the type 3 zymogram (Table 1). 2) Factorial basis of the three zymograms The type 1 lacked major band 8E-B as compared to the type 2 zymogram. While the type 3 had extra bands 8'E and 10E. To clarify the factorial basis of 8E-B band, F1 and F2 generations of the cross, Ae. squarrosa var. strangulata KUSE 2118 (type 2) x Ae. squarrosa var. strangulata KUSE 2135 (type 1), were studied, In the F1, type 2 zymogram was observed. In the F2, type 1and type 2, segregated in a 1:3 ratios as shown in Table 2, indicating that the production of 8E-B bands is controlled by a single dominant gene. |
| 1) The work was supported in part by a Grant-in-Aid (No. 134050) from the Ministry of Education. |
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