摘要
Maize landraces White Dent and Golden Queen played a very important role in the pre-hybrid era of maize production in China. However, dozens of accessions with the same names of White Dent and Golden Queen are preserved in China National Genebank （CNG）. The present study investigated the genetic diversity of these two important groups of maize landraces, as well as the relationships within and among them. Thirty-four landrace accessions with the name of White Dent and 10 with Golden Queen preserved in CNG were fingerprinted with 52 simple sequence repeats with tailed primer M13. Summary statistics including average number of alleles per locus, gene diversity/expected heterozygosity, and observed heterozygosity were carried out using PowerMarker ver. 3.25 software. The test of Hardy-Weinberg equilibrium （HWE） and linkage disequilibrium （LD） of all the 44 maize landrace accessions were also performed by PowerMarker. We observed a significant differentiation in terms of the average number of alleles between White Dent and Golden Queen （6.44 alleles per locus in White Dent, 4.48 in Golden Queen）, while both groups of maize landraces had a relatively high but similar gene diversity （0.61 of White Dent, 0.63 of Golden Queen）. The fixation index （FST） was only 0.0044, while the percentage of loci deviated from Hardy-Weinberg equilibrium within these two groups of White Dent and Golden Queen was 32.69 and 3.92%, respectively. The rather high genetic diversity and average number of alleles per locus confirmed that both groups of landraces had a rather broad germplasm base. The extremely low fixation index showed that there was little genetic variation between White Dent and Golden Queen and the molecular variation within these two groups was remarkably high, indicating no genetic drift between White Dent and Golden Queen and suggesting different improvement approaches to these two important groups of landraces. Hardy-Weinberg equilibrium test revealed that the group of White Dent was deviated from HWE, whereas Golden Queen was under HWE.
Maize landraces White Dent and Golden Queen played a very important role in the pre-hybrid era of maize production in China. However, dozens of accessions with the same names of White Dent and Golden Queen are preserved in China National Genebank （CNG）. The present study investigated the genetic diversity of these two important groups of maize landraces, as well as the relationships within and among them. Thirty-four landrace accessions with the name of White Dent and 10 with Golden Queen preserved in CNG were fingerprinted with 52 simple sequence repeats with tailed primer M13. Summary statistics including average number of alleles per locus, gene diversity/expected heterozygosity, and observed heterozygosity were carried out using PowerMarker ver. 3.25 software. The test of Hardy-Weinberg equilibrium （HWE） and linkage disequilibrium （LD） of all the 44 maize landrace accessions were also performed by PowerMarker. We observed a significant differentiation in terms of the average number of alleles between White Dent and Golden Queen （6.44 alleles per locus in White Dent, 4.48 in Golden Queen）, while both groups of maize landraces had a relatively high but similar gene diversity （0.61 of White Dent, 0.63 of Golden Queen）. The fixation index （FST） was only 0.0044, while the percentage of loci deviated from Hardy-Weinberg equilibrium within these two groups of White Dent and Golden Queen was 32.69 and 3.92%, respectively. The rather high genetic diversity and average number of alleles per locus confirmed that both groups of landraces had a rather broad germplasm base. The extremely low fixation index showed that there was little genetic variation between White Dent and Golden Queen and the molecular variation within these two groups was remarkably high, indicating no genetic drift between White Dent and Golden Queen and suggesting different improvement approaches to these two important groups of landraces. Hardy-Weinberg equilibrium test revealed that the group of White Dent was deviated from HWE, whereas Golden Queen was under HWE.
基金
supported by the Special Program for Crop Germplasm Resources of the Ministry of Agriculture [(NB07-2130135-(25-30)-05]
Natural Science Foundation of Beijing (6071003)
Innovation Platform Program for Basic Research of Agricultural Breeding in Beijing (YZPT02-06)
Scientific and Technological Key Project in Chongqing for Elite Variety Innovation of Rice and Maize (CSTC 2007AB1045)
