| Simple sequence repeat(SSRs) has been used to study genetic diversity of 50 Maize inbred lines of Henan . 95 SSR primers selected from all 140 primers gave distinct profiles amplified in the sample of 50 inbred lines, 95 SSR primers produced 485 polymorphic amplified fragments :the average number of alleles per SSR locus was 5.11 with a range from 2 to 14; The polymorphism information content (PIC) for SSR loci varied from 0.187 to 0.764 with an average of 0.642;Simutaneously, 16 inbred lines ,which embrace 87-1 87-3 and 14 other inbred lines on behalf of different heterotic groups selected from those 50 maize inbred lines,are crossed in dialed cross style according to Griffing IV design .Lattice design was employed to analyze GCA and heterosis of yield, in which 120 maize hybrids were involved . 16 Maize inbred lines were classified eight groups based on yield heterosis and combining ability. The parent's germplasm and the mechanism of heterosis of Yuyu 22 have been studied based on the result of the cluster analysis according to two kinds of method; The relationship between 120 crosses' heterosis and allele heterozygosity or the genetic distance according to Nie-Li method based on SSR markers has also been studied . In addition, Studing on their parent and their planting area of main corn hybrids authorized in henna from 1981 to 2003, which planting area are over 3.4×l04 hm2 (data come from main maize planting area's statistics of henan done by Henan Seed Management Station), the maize germplasm base and the main utilizing models of heterosis is summarized.The result shows that:1 The genetic distance between 87-1 87-3 and P138 Xul78, which have distinctly tropic germplasm, was shorter than that of others and it could be concluded that inbred lines 87-1 87-3 possess partially tropic germplasm;2 The genetic distance between 87-1 and Zong 3 was long in two kinds of cluster analysis chart, they have many important complement characters such as ear trait;3 In this paper, the relationship between each of 120 crosses' heterosis value and allele heterozygosity of SSR loci between the two response inbred lines is not related; In addition, in low heterosis crosses ,to some extent ,heterosis and genetic distancebased on SSR markers done by Nie-li method have related, while in high or middle heterosis crosses , the relation coefficiency is very low, So it is restricted to predict heterosis between two inbred lines based on allele heterozygosity of SSR loci or the genetic distance based on SSR markers done by Nie-li method.4, The main maize germplasm in Henan during 1981-2003 was Mo 17 heterosis groups, Improved reid, Tangsipingtou and ludahonggu; P heterosis groups and Synthesis heterosis groups has been used increasingly in recent five years, The maize germplasm in Henan has been extended greatly. According to the cluster analysis of inbred lines mainly used in authorized hybrids in Henan based on SSR markers, twenty main models of Maize heterosis utilization has been used in 1981-2003. Seven of twenty models have widely been used: Inproved reid × tangsipingtou Mol7 × ludahonggu Inproved reid × ludahonggu P Heterosis groups × Synthesis heterosis groups Mo17× tangsipingtou Inproved reid×P Heterosis groups tangsipingtoux Synthesis heterosis groups. These models may be used greatly in future: P Heterosis groups × Synthesis heterosis Inproved reid× qita Inproved reid × tangsipingtou P Heterosis groups × qita. |
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