BEIJING, CHINA
Institute of Genetics
Chinese Academy of Sciences

Quantitative trait variation induced by space flight

— Zeng, M; Zeng, Z; Ji, H

In our previous papers, we described a significant influence of space flight on maize seeds’ progeny. Some mutant types of qualitative traits have been obtained [MNL 74:2–3, 75:4, 77:3–4, Chinese Space Science and Technology 18(6):63–67, 23(6):64–68]. There was also some variation for quantitative traits from the Yi01-4-1, U8112, Me141 and MD185 inbred lines. Some characters and properties of the variations obtained for quantitative traits were as follows:

• First type, special high plant and dwarf plant variation, all resistant to B. maydis and E. turcicum. For Mut1 and Mut2, the plant heights are 191.3cm and 182.0cm, respectively, which are 33.68% and 27.18% higher than control (CK, Yi01-4-1). Ear heights are higher than control by 95.14% and 82.28%, respectively. Lengths of the leaf at the ear site are 19.34% and 13.99%. Widths of the leaf at the ear site are 14.29% and 30.0%. Tassel lengths are 11.56% and 20.48%. Ear lengths are 33.92% and 24.10%. Ear diameters are 37.14% and 37.14%. Kernel numbers of each row are 40.9% and 50.0%. Weights of 100 kernels are 69.63% and 41.88%. Per-ear weights are 121.48% and 96.88%. Kernel weights per ear are 131.94% and 99.40%. Lengths of ear handle are 20.0% and 20.0% more than CK, respectively. Resistance to B. maydis and E. turcicum is stronger than that of CK. But leaf number, number of kernel row, days from seedling to silking and ear number per plant don’t change all. The frequency of the mutation is 3.1%. For Mut5: the plant heights are 157.0cm, 50.1cm, and ear heights are 17.14%, 39.5% lower than control (CK, U8112). The tassel length is 9.05% less than CK. Leaf number, ear length, ear diameter, weight of 100 kernels, days from seedling to silking, etc., don’t have large changes. However, other traits do have large changes. The length and width of the leaf at the ear site are 70.57% and 6.38% more than CK, respectively. The kernel number of each row, number of kernel row, ear weight, kernel weight per ear, are 10.71%, 16.67%, 25.83%, 22.82% more than CK, respectively. The frequency of the mutation is 1%.


• Second type, the variation of ear length and kernel number of each row. Mut8, Mut9: the ear lengths are 17.1cm and 18.5cm respectively, longer by 33.59% and 44.53 than control (CK Me141). The kernel number of each row is 34.2 grains and 32.3 grains respectively, 55.45% and 46.81% greater than CK. The kernel weights per ear are 40.40% and 41.49% more than CK. The ear weights are 39.71% and 41.00% more than CK. The plant height, ear height and length of ear handle are significantly longer, but other traits are not significantly changed, compared with its control. The frequency of the variation is 2.3%.


• Third type, the variation of kernel weight per ear and per-ear weight. Mut6, Mut7: the kernel weights per ear are 120.3g and 107.5g, respectively, 69.44% and 51.41% more than control (CK, U8112). The per-ear weights are 143.0g and 130.0g, respectively, 70.23% and 54.76 more than CK. The lengths of the leaf at the ear site are 78.23% and 67.70%. Ear lengths are 20.96% and 14.37%. Numbers of kernel rows are 16.67% and 16.67%. Kernel numbers of each row are 14.29% and 17.86%. Weights of 100 kernels are 15.35% and 15.35%. Tassel branch numbers are 36.04% and 37.84% more than CK, respectively. But tassel length and days from seedling to silking are a bit less. Other traits don’t change compared with the control. The frequency of the mutation is 2.8%.


• Fourth type, the variation of the leaf-blade open and flat. Mut11: the leaf-blade is open and flat (9°), different from its control (CK, MD185, su1 kernel type). On the contrary, leaf-blade of the control is semi-erect (about 135°). The expression of agricultural quantitative traits was as follows: The leaf length at the ear site is 96.0cm, 25.65% longer than CK. The tassel branch number, ear length, kernel weight per ear, and length for leaf-blade of husk top are 31.91%, 14.02%, 23.08%, and 11.11% more than CK, respectively. The resistance to P. inflatum, P. aphanidermatum, F. moniliforme and F. graminearum, and to holci-sorghi are raised (R, MR→HR). On the contrary, the tassel length is significantly short, 54.85% shorter than CK. But the plant height, ear height, leaf width at ear site, ear diameter, leaf number, number of kernel rows, kernel number per row, weight of 100 kernels, days from seedling to kernel maturing, length of ear handle, ear number per plant, etc., are not different from CK.

The author wishes to call attention to a recently-published paper: Zeng M., Zeng Z., Ji H., Analysis on Space Special Environment Induced Mutant in Maize. Chinese Space Science and Technology, 23(6): 64–68. 2003.

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