Identification Of Important Genomic Regions In Founder Parents Transmitted To Their Derived Inbred Lines In Maize

Maize (Zea mays L.) is the second largest crop in China. The development of maize production in China has obtained tremendous achievement since the 1950s. The extension and application of maize hybrids have played a decisive role in maize production. A large number of maize hybrids used in production have the pedigrees of the following inbred lines, i.e. Huangzaosi, Mo17, Ye478, Dan 340 and Zi330. Because many important inbred lines were derived from these inbreds, they are also called as"founder parents". Understanding genetic relationships among these founder parents and their derived inbreds will facilitate the development of new founder parents and thus provide new germplasm to breeding programs.This research firstly analysed the genetic difference of 39 accessions of the founder parents with same name but from different institutions by SSR molecular markers. And then a genome-wide scanning was conducted on a total of 93 accessions including the five founder parents and their derivatives using 289 SSR markers. Important genomic regions in the founder parents transmitted to their respective derived inbred lines were identified. The major results are as follows.1. Totally 39 accessions of the founder parents with same name but from different institutions were analyzed by 116 SSR markers. A total of 400 alleles were detected, with an average of 3.45 alleles per SSR marker. The results showed that Huangzao, Ye478 and Mo17 and their respective derivatives had only small genetic changes.2. The results of the genome-wide scanning on the 93 accessions including the five founder parents and their derivatives using 289 SSR markers indicated that 2845 alleles were detected, with average of 9.84 alleles per SSR markers and the range of 2 to 28. It was also found from a cluster analysis that the derived inbred lines from Huangzaosi, Mo17 and Ye478 corresponded to the respective pedigrees well.3. Important genomic regions in Huangzaosi, Mo17 and Zi330 were identified according to the results of genomewide scanning. 1)Fifty genomic regions in Huangzaosi were detected to possibly be transmitted to its derived lines, involving 78 SSR loci and covering 336.7cM, 195 cM, 191.4 cM, 283.6 cM, 167.9 cM, 201.1 cM, 91.9 cM, 105.9 cM, 32.4 cMand 285.1 cM (totally 1891 cM) on chromosome 1 to 10, respectively. By the comparison with the results of QTL analysis carried out previously, it was confirmed that the region from umc1186 to umc1656 on chromosome 6 associates with resistance to maize dwarf mosaic virus. (2) 66 genomic regions in Mo17 were detected to possibly be transmitted to its derived lines, involving 96 SSR loci and covering 416.8cM, 216.3 cM, 132.5 cM, 174.2 cM, 80.8cM, 94.3 cM, 122.4c M, 233 cM, 197.1 cMand 137 cM(totally2004.4 cM) on chromosome 1 to 10, respectively., (3) 69 genomic regions in Zi330 were detected to possibly be transmitted to its derived lines, involving 89 SSR loci and covering 370.1cM, 145 cM, 97.8 cM, 129.6 cM, 139.4 cM, 163.8 cM, 147.5cM, 233 cM, 37cMand 199.8 cM (totally 1663cM) on chromosome 1 to 10, respectively.