II. 3. Xenic shrunken endosperm associated with the high lysine mutant High Amylose Glacier.
H. Ahokas, Department of Genetics, University of Helsinki, P. Rautatiekatu 13, 00100 Helsinki 10, Finland. "R"
The High Amylose Glacier first described by Merritt (1967) has been shown to be a high lysine, normal or near-normal protein mutant (Merritt and Walker, 1969;Poneranz et al., 1972; Ullrich and Eslick, 1978) and has been called amo1 by Ullrich and Eslick (1978). In the test environments of the USA, the mutant was found to produce significantly lighter kernels (94.9% of the seed weight of normal Glacier), but the kernels were reported not to have a visibly shrunken endosperm (Ullrich and Eslick, 1978).
The stocks were obtained from Dr. S. E. Ullrich. Normal Glacier and the amo1 mutant were grown at the normal plant density in Finland in the 1978 season. At the full ripe stage, the amo1 heads were observed to carry a small depression, resembling the effect of a weak shrunken endosperm gene, in the center of the lemmas. Tearing of the lemma revealed a distinct depression on the dorsal surface of the caryopses. This effect was quite clear on the central rows of the six-rowed heads of the mutant, but was not found on kernels of normal Glacier.
Since I had performed a number of crosses with High Amylose Glacier, the ripe F1 heads were studied for eventual shrunken kernels. The result appears in Table 1. In the six-rowed material, only the central rows were classified. Most of the crosses seem to display the segregation typical of the F2 kernels of a sex mutant. An excess of plump kernels was observed in the crosses with HA 22, Hankkija's Eero, and Washonupana. Because amo1 displays dosage effect (Walker and Merritt, 1969), the departure from the 1:3 ratio in the cross with Washonupana (waxy, short awned, naked Compana) can be ascribed to the waxy gene. The distortion by HA 22 and by Hankkija's Eero are obscure at present. HA 22 evidently carries a spontaneous translocation, since its F1 hybrids show a sterility of about 29% (Table 1) (see Burnham et al., 1954). Recent greenhouse material provides evidence that Crypt, CI 1090 (see Ahokas, 1979) does not distort the F2 segregation.
Table 1. Segregation of F2 kernels in F1 hybrids with High Amylose Glacier as one of the parents.
It may be concluded that High Amylose Glacier carries a factor which behaves like a sex gene and is evidently sensitive to environmental conditions. Because shrunken endosperm and changes in the composition of endosperm are pleiotropic effects of a single gene (Ullrich and Eslick, 1978), it is highly probable that the amo1 is also responsible for the sex-type behavior.
Acknowledgment:
The work was done under the auspices of the Academy of Finland.
References:
Ahokas, H. 1979. Further results on the suppression of shrunken endosperm in high lysine mutants. BGN 9:3-7.
Burnham, C.R., F.H. White, and R. Livers. 1954. Chromosomal interchanges in barley. Cytologia 19:191-202.
Merritt, N.R. 1967. A new strain of barley with starch of high amylose content. J. Inst. Brew. 73:583-585.
Merritt, N.R. and J.T. Walker. 1969. Development of starch and other components in normal and high amylose barley. J. Inst. Brew. 75:156-164.
Pomeranz, Y., R.F. Eslick, and G.S. Robbins. 1972. Amino acid composition and malting and brewing performance of high-amylose and Hiproly barleys. Cereal Chem. 49:629-635.
Ullrich, S.E. and R.F. Eslick. 1978. Lysine and protein characterization of spontaneous shrunken endosperm mutants of barley. Crop Sci. 18: 809-812.
Walker, J.T. and N.R. Merritt. 1969. Genetic control of abnormal starch granules and high amylose content in a mutant of Glacier barley. Nature 221:482-483.
