| The effect of nucleo-cytoplasmic interaction on the
endosperm protein in wheat (preliminary) M. SASAKI, Y. YASUMURO and N. NAKATA Faculty of Agriculture, Tottori University, Tottori 680, Japan KIHARA (1963, 1973) suggested that "cytoplasmic heterosis" of nucleo-cytoplasm hybrids can be used for plant breeding as a new source of genetic variability. In this regard, different alien cytoplasmic ditelocentric Chinese Spring lines are being developed for the study on the effect of nucleo-cytoplasmic interaction on the endosperm protein quantity and quality in wheat. As a preliminary step to this program, the effect of alien cytoplasms was studied on the grain protein content (%) in the wheat variety, Chinese Spring. One hundred and eight plants of 8 alien and one original cytoplasmic Chinese Spring euploid lines were grown in three replications having 4 plants randomised within each replicate block in the field at Tottori in 1975-1976. The Kjeldahl protein analysis of seeds obtained by bagging was made for each plant. For the male sterile Chinese Spring lines with T. timopheevi or Ae. caudata cytoplasm, seeds obtained by hand made pollination were used. The variance analysis was made for 27 mean values consisted of 3 block means for each material line. The Kjeldahl % grain protein (N% x 5.83) of 9 different Chinese Spring lines are shown in Table 1. The differences among lines are significant for the % grain protein, and those lines which have T. timopheevi, Ae. caudata, Ae. umbellulata or S. cereale cytoplasm were higher in the % grain protein than the original Chinese Spring line. However, these high protein lines were in general low in seed fertility and yield, short in culm length. And, the % grain protein were highly correlated negatively to those characters, but positively to 1000-grain weight (Table 2 and Fig. 1). The latter relation suggests that the bran protein did not contribute to the higher % grain protein of lower seed fertility lines. The relationships of this type shown in Table 2 between the % grain protein and the other characters seem to be quite general in a certain material having a large seed fertility variation. The same relationships were also observed for the 11 ditelocentric Chinese Spring lines grown in the glass-house in the same season (unpublished). The analysis of variance showed that in this experiment differences between the original and alien cytoplasms are not statistically significant for the corrected % grain protein based on the regression of the % grain protein (Y) and grain number per spikelet (X), Y = 17.7-3.209 (X-1.5). These results suggest that (1) under the certain nitrogen source and culture conditions, smaller sinks such as shorter culm, fewer tillers, seeds and yield cause higher accmulation of protein (nitrogen) into the seed sink making seeds heavier, and (2) the cytoplasm affects less directly on the % grain protein, but much indirectly through the other yield component characters. However, that those lines with the caudata, squarrosa or timopheevi cytoplasm are still higher than the line with the original cytoplasm in the corrected % grain protein, though the differences are not significant, requires a further study in detail on the effect of alien cytoplasms on the grain protein quantity and quality in wheat. An analysis for amino acids composition of the grain protein are under way. Acknowlegements: We are grateful to Drs. H. FUKASAWA, M. MURAMATSU, K. TSUNEWAKI and T. LELLEY for providing us with the source line seeds of alien cytoplasms. The work has been supported in part by a Grant-in-Aid (No. 1668/RB) from the International Atomic Energy Agency (IAEA). Literature Cited KIHARA, H. 1963. Nucleus and chromosome substitution in wheat and Aegilops.III. Chromosome substitution. Seiken Ziho 15: 12-23. KIHARA, H. 1973. Characters of Aegilops squarrosa cytoplasm. Proc. 4 Intern. Wheat Genet. Symp. Columbia, Missouri pp. 351-353. TSUNEWAKI, K., Y. MUKAI, T. Ryu ENDO, S. TSUJI and M. MURATA 1976. Genetic diversity of the cytoplasm in Triticum and Aegilops. V. Classification of 23 cytoplasms into eight plasma types. Japan. J. Genetics 51: 175-191. (Received Nov. 28, 1976) |