Analysis on new CMS types Bao I, Bao II in maize (Zea mays L.) --Yan, Z, Zeng, M, Yang, T The purpose of this paper is to present the results of the analysis and determination on new CMS types Bao I, Bao II in maize (Zea mays L.). Population 157 was used for breeding and selection experiments, 86 inbred lines from various provinces of China and different countries were used for determinative materials in test cross and inoculation experiments with H. maydis, H. turcicum.

The new types of cytoplasmic male sterility Bao I, Bao II were bred by using the approaches of self pollination, selection and inoculation determination etc. In test-cross of 86 inbred lines to Bao I type, 45 inbred lines were restored to fertility, covering 52.3% of the total tested lines, nine were partly restored to fertility, covering 10.5%, 32 lines kept up sterility, covering 37.2%. In test cross of 80 inbred lines to Bao II type, all tested lines kept up sterility (see Table 1).
 
 
Cytoplasm 
Item Bao I Bao II
Full restoration (_) 45 lines 0
Partial restoration (±) 9 lines 0
Full maintenance (_) 32 lines 80 lines

The results obtained from evaluation of resistance to Helminthosporium maydis have shown that E157-cms-Bao I is infected with race 0, but resistant to race T, quite resistant to race C; F157-cms-Bao II is mildly infected with race 0, but highly resistant to race T, quite resistant to race C. Resistance of CMS lines and its maintainer is the same (see Table 2).

Table 2. Evaluation of resistance to southem blight disease (H. maydis).
 
  Race O     Race C     Race T    
No.of line Disease degree Disease state coefficent Resistance Disease degree Disease state coefficent Resistance Disease degree Disease state coefficent Resistance
E157-cms-Bao I 4.0 78.71 s 0 0 Q.R 1.0 20.1 R
E157 4.0 77.00 s 0 0 Q.R 1.0 21.1 R
U8112-cms-Bao I 3.0 57.85 m.s 0 0 Q.R 0.5 13.2 H.R
U8112 3.0 57.42 m.s 0 0 Q.R 0.5 13.5 H.R
M017-cms-Bao I 1.0 18.33 R 0 0 Q.R 0.5 8.9 H.R
M017 1.0 18.38 R 0 0 Q.R 0.5 9.2 H.R
F157-cms-Bao II 4.0 78.13 s 0 0 Q.R 1.0 21.2 H.R
F157 4.0 77. 93 s 0 0 Q.R 1.0 22.3 R
U8112-cms-Bao II 3.0 51.03 m.s 0 0 Q.R 0.5 11.5 H.R
U8112 3.0 51.11 m.s 0 0 Q.R 0.5 11.3 H.R
478-cms-Bao II 0.5 11.92 H.R 0 0 Q.R 0.5 9.8 H.R
478 0.5 11.85 H.R 0 0 Q.R 0.5 9.7 H.R
Zhongdan 2(cms-Bao I) 0.5 12.22 H.R 0 0 Q.R 0.5 10.5 H.R
Zhongdna 2(N) 0.5 11.85 H.R 0 0 Q.R 0.5 9.8 H.R

Notes: R�Resistance; H.R�High resistance; S�susceptivity; m.s�mid-susceptivity; Q.R�Quite resistant.
 
 
 
 

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