| The data on protein content (Table 4) from the
F3 progenies of critical monosomic lines confirm the F2
results in both the crosses. The average grain protein content in the F3
progenies of each critical line was higher than that in their disomic control.
Different F3 families in each critical line showed very little
variation. Differences between different F3 families seldom exceeded
more than 2 DBC units. The average protein content in different critical
monosomic lines also did not show much variation. Taking all the critical
monosomic lines together for each cross, the range of variation in protein
content was lower in the F3 of critical lines than in the disomic
control. In the Sonora-64 cross, the protein content in DBC absorption units
varied from 0.24 to 0.28 in the critical monosomics as against 0.21 to 0.27
units in the F3 of disomic control. Similarly, in the Lerma Rojo
cross it ranged from 0.24 to 0.27 units in the critical lines as against
0.20 to 0.26 in the F3 of disomic control. The DBC absorption
value for F2 bulk was 0.24 in both the crosses, whereas in F3
the DBC value was 0.23 units. In the critical monosomic lines also the average
protein content in the F3 was slightly less than that in their
corresponding F2 parent. This indicates that effects other than
those caused by additive gene action for grain protein content persist in
the F2 generation. In the F3 generation, a few families
showed a protein content higher than that of the donor parent, more particularly
in mono-3A, -3B and -5A in the Sonora-64 cross and in mono-3B and -3A of
the Lerma Rojo cross. These chromosomes might have genes for protein synthesis
with a better penetrance. Wheat strains containing a high protein content have been developed in India and Mexico using Sonora-64 and Lerma Rojo as the base material. This suggests that Sonora- 64 and Lerma Rojo might have a few non-identical factors controlling protein content, which is in agreement with the present findings. JHA(7) located the factors for grain color of Sonora-64 and Lerma Rojo on chromosomes 3B and 3A respectively. The present study shows that one of the factors for high grain protein content and grain color in Sonora-64 and Lerma Rojo are located on the same chromosome. This might explain why some amber grain mutants isolated from Sonora-64 had simultaneously a higher protein content. A similar situation might prevail in Lerma Rojo also and this is probably why Pusa Lerma, an induced amber-grain mutant from Lerma Rojo, has shown a higher protein content than the parent strain (AUSTIN, personal communication). Literature 1. SWAMINATHAN, M. S. 1968. Five Years of Research on Dwarf Wheats. I.A.R.I., pp. 1-46. 2. BORLAUG, N. E. 1968. Proc. 11th Hard and Red Winter Joint Wheat Workers Conference. pp. 8-23. 3. JOHNSON, V.A., P.J. MATTEM and J. W. SCHMIDT 1968. Ibid., p-56. 4. AUSTIN, A.,V. K. HANSLAL and H. D. SINGH 1968. J.P.G. School, I.A.R.I., 6: 131-142. 5. UDY, D. C. 1956. Cereal Chem. 33: 190. 6. KAUL, A. K., R. D. DHAR, M. S. SWAMINATHAN and G. AHNSTROM 1969. Curr. Sci., 14: 330. 7. JHA, M. P. 1970. (In press). 8. SPIES, J. R. and D. C. CHAMBERS 1949. Analytical Chem. 21: 514-523. (Received Nov. 11, 1970) |
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