II. 38 Amino-acid composition of seed protein in diploid and autotetraploid high protein-high lysine barley strains.
S.P. Tiwari and H.C. Bansal, Division of Genetics and Nuclear Research Laboratory, I.A.R.I., New Delhi-11O 11O 012, India.
In our efforts to breed barley varieties with high protein and/or high lysine content in seeds, using mutagenesis and subsequent hybridisation, some promising strains have been isolated. Amino-acid composition of these and of an autotetraploid has been analysed using Hiproly strain for comparison (Table 1). Except Notch-2, which has a dorsal depression on seeds, and its autotetraploid, these strains also possess desirable agronomic characters. Strain BM-21, though having only about 9.5% total seed protein, has the high lysine content of 3.61 g/16 g N.
Autotetraploidy in Notch-2 resulted in the increased protein content, the main increase being in glutamic acid. Proportion of lysine did not show appreciable change. Since total seed protein in barley is reported to be quantitatively inherited (Olsen, 1974) and high lysine content is due to the recessive monogenic effect (Karlsson, 1972), these results are genetically explainable as to the presence or absence of dose effect. Substantial increase in the content and proportion of glutamic acid, following autotetraploidy, is indicative of its being controlled by additive type of gene action. These observations could also account for redistribution of soluble protein fractions due to autotetraploidy observed by us (Tiwari et al., 1976) owing to differential increase in the individual amino-acids.
References:
Karlsson, K.E. 1972. Linkage studies on a gene for high lysine content in Hiproly barley. Barley Genet. Newsl. 2:34-36.
Olsen, O.A. 1974. Ultrastructure and genetics of the barley line Hiproly. Hereditas 77:287-302.
Tiwari, S.P., H.C. Bansal, and R.A. Pai. 1976. Protein estimation in induced autotetraploids of Notch-2, a high protein-high lysine mutant of barley. Barley Genet. Newsl. 6:75-76.
