ZHENGZHOU, CHINA
Henan Agricultural Academy
WUHAN, CHINA
Huazhong Agricultural University

Polymorphisms of synthesized populations from Chinese and exotic populations at 17 isozyme loci
--Tie, SG, Zheng YL, Liu, JL

In order to create new germplasm for recurrent selection, we used elite southwestern China local varieties Lanhuazhao (L) and Wuxi (W) with exotic germplasm Lancaster (L), BSSSR (B), Mohuangjiu (M), and Suwan2 (S) to synthesize 4 new C0 populations, LBM, LLS, WBM, and WLS. The six populations among LBM, LLS, WBM, WLS and U.S. BSSSR and BS16 were analysed for isozyme variation at 17 enzyme marker loci for 8 isozymes. A random sample of seedlings growing at 25 C for 5 days from each population was assayed by horizontal potato starch (SIGMA Co.) gel using the method of Stuber et al. (1988). Mo17 and Oh43 were included as standards on each gel to aid gel reading. The method of denoting alleles (allozymes) and genotypes for locus has been described in detail by Stuber et al. (1988) and Kahler (1983). Gene diversity or heterozygosity was calculated for populations for each locus as follows: H=1- (fi)2 where fi is the frequency of the ith allele. The numbers of alleles detected for the 17 isozyme loci assayed in the 6 populations are given in Table 1. A total of 47 alleles was observed in 17 loci among populations assayed, with an average of 2.76 alleles per locus. The distribution of the alleles among the loci and populations is not uniform. The percentage of polymorphic loci ranged from 64.7 to 76.5. These data suggested that the 4 C0 populations from China were rich in allelic diversity as compared to U.S. BSSSR and BS16. For six populations, gene diversity (heterozygosity) for 17 isozyme loci is presented in Table 2. The total heterozygosities among each locus and population ranged from 0 to 66. The total heterozygosities of 17 loci among 6 populations ranged from 22.6 to 29.0. The results showed that the 4 C0 populations and BS16 and BSSSR maintain rich isozyme variation and also provide a review that the genetic bases of maize synthesized populations maintain abundant and plentiful genetic variation.

Table 1. Allele number at 17 isozyme loci in 6 populations.
 
Loci WBM LBM LLS WLS BSSSR BS16
adh1 2 2 2 2 2 2
cat3 2 2 2 2 1 2
e1 2 3 3 2 3 2
e2 1 2 1 2 2 1
e8 2 3 2 3 3 3
glu1 2 5 3 2 3 4
got1 1 1 1 1 1 1
got2 1 1 3 2 1 3
got3 1 1 1 1 1 1
mdh1 3 3 3 2 3 2
mdh2 4 3 3 3 2 3
mdh3 2 2 1 1 2 2
mdh5 2 2 2 2 2 2
mmm1 1 1 1 1 1 1
pgd1 3 3 5 3 3 4
pgd2 4 3 4 3 3 3
phi1 2 2 2 1 1 2
X 2.059 2.294 2.294 1.941 2.000 2.235
Polymorphic loci (%) 70.6 76.5 70.6 70.6 64.7 76.5

Table 2. Gene heterozygosities (gene diversity) for 17 isozyme loci of 6 maize populations.
 
Loci WBM LBM LLS WLS BSSSR BS16
adh1 39 25 21 10 60 7
cat3 18 9 32 32 0 4
e1 40 61 57 44 60 40
e3 0 42 0 12 28 0
e8 37 48 32 41 19 61
glu1 28 61 12 18 63 27
got1 0 0 0 0 0 0
got2 0 0 12 37 0 43
got3 0 0 0 0 0 0
mdh1 44 20 37 4 36 32
mdh2 47 54 66 57 39 56
mdh3 24 19 0 0 27 18
mdh5 41 20 29 6 45 30
mmm 0 0 0 0 0 0
pgd1 58 57 64 60 55 58
pgd2 66 52 63 66 46 58
phi1 11 6 18 0 15 0
H 26.6 27.9 26.1 22.4 29.0 26.5


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