| Genetic diversity is the summation of different colonies in one species or different individual genetic variation in one colony. The research on genetic diversity experienced the following stages: agronomic character morphological markers, comparative analysis of quality character,, biochemical marker (isozyme and seed store protein), and latest research on DNA molecular marker in the field of molecular biology, that indicates difference of internal germplasm. The study on genetic diversity study plays a significant role in the collection, valuation, preservation and utilization of biotic germplasm resources. The following conclusions were made via investigate 17 agronomic characters of 80 waxy corn inbred lines(40 yellow, 20 white, 13 black and 2 red ones), cluster analysis and genetic distance, measure content of chief biochemical component, PAGE cluster analysis of seed store protein(salt-soluble protein), SSR molecular marker fingerprint, total diallel cross of randomly chose 7 inbred lines, measure the combining ability and heterosis.1. Abundant genetic diversity of 80 waxy corn germplasm were showed on agronomic character, quality character, DNA inheritance material. The 17 agronomic characters and quality characters express great range of variance, different significant of variance analysis.2. By analyzing the chief components of 17 important quality characters and calculating according to the 85% contribution rate, we got 7 chief component factors. The geometrical distance difference among these 7 between the 2 inbred lines i. e. genetic distance. 80 inbred lines are divided 9 groups, according to the 4.15 genetic distance. The 1 st included 2 inbred lines, which are N76 and N09. There is only N66 in the 2nd. There are 5 in the 3rd, which are N68, N67, N49, N74 and N42. There are N05 and N37 in the 4th. There is only N57 in the 5th. In the 6th, there are 19 inbred lines, which are distributing into 2 sub—groups. In the 1st sub—group, it included N80, N62, N72, N71 and N10. In the 2nd sub—group, it included N41, N77, N44, N63, N70, N46, N60, N43, N15, N30, N26, N78, N19, N06. In the 7th group, there are 7 inbred lines, which are N56, N55, N54, N53, N48, N31, and N18. In the 8th group contains 2 inbred lines which are N04, N21, there are 41 inbred lines in the group 9th, which are divided into 4 sub—groups. In the 1st, it include N73, N58, and N52. In the 2nd, they are N39, N17, N16, N47, N12, N61, N24, N38, N33, N14, and N07. In the 3rd, there are 2 inbred lines, which are N29, and N13. In the 4th, it include N75, N65, N69, N35, N79, N27, N20, N11, N08, N64, N25, N51, N03, N59, N02, N32, N28, N50, N36, N23, N40, N24, N22, N01. The clustering analysis results of agronomic character shows that different phenotypes of inbred lines are distributing in different groups.3. There are great range in the content of chief nutritious quality component of waxy corn germplasm resources. The content of starch, protein and fat variance range is 58.05—76.20%, 7.31—13.97%, and 3.00—6.68% respectively, the average value is 67.69%, 11.15% and 4.93%. The starch is 100% amylopectin, which is remarkable negative correlation with protein, and the correlation coefficient is -0.1908. The fat and starch is positive correlation, and the correlation coefficient is 0.1786.4. The PAGE map of 80 waxy corn inbred lines was divided 13 special bands according migrate rate, and cluster 6 groups(genetic distance 0.27 as standard), the 3rd group was divided 2 sub-groups further at the site of genetic distance 0.14, the 4th group was divided 3 sub-groups at site 0.22, there is only 1 line in the 1st groups i. e. N16, and so is the 2nd group that is N51, in the 3rd group, there are 7 lines divided 2 sub-groups, which is N71, N70, N68, N67; and N39, N65, N66. In the 4th group there are 68, which divided 3 sub-groups, In the first sub-groups, they are N10, N06, N05. In the second, they are N74, N69, N11, N46, N43, N45, N19, N28, N17, N08, N15, N13, N07, N14, and N04. In the third, it includes the following: N63, N62, N56, N55, N57, N50, N38, N27, N25, N24, N12, N49, N47, N80, N79, N76, N44, N42, N41, N78, N77, N61, N60, N22, N21, N54, N53, N64, N58, N52, N59, N37, N36, N35, N34, N33, N32, N31, N30, N23, N20, N72, N40, N29, N26, N48, N09, N75, and N03. In the 5th group, only N73 is included. In the 6th, N02, and NO 1 are included. The genetic distance variance range from 0.00 to 0.46.5. 22 pair primers of SSR distribute in 10 chromosomes of maize genome, each of which can check and measure 2-4 alleles. Altogether there are 60 morphological fragment, average of which is 2.73. The variance range of genetic distance of 80 waxy corn inbred lines is from 0.045 to 0.946.6. As the standard of genetic distance 0.55, the 80 waxy corn inbred lines cluster 9 groups via cluster analysis of SSR. Among them, the 2nd group is divided into 3 sub—group at the site of 0.46. The 5th is into 2 at 0.490. So is the 7th and 8th at 0.46, 0.46 respectively. The 9th is into 4 at 0.493. The following is the distribution situations: the 1st group include N12. The 2nd are N69, N80, N79, N73, N71, N70, N74, N68, N67, N65, N63, N61, N66, and N52. The 3rd are N50 and N48. The 4th is N72. The 5th are N64, N59, N58, N46, N44, N62, N57, N54, N53, N60, N56, N55, and N43. The 6th are N16, N42, N16, and N41. The 7th are N40, N36, N25, N39, N37, N78, N77, and N09. The 8th are N76, N45, N47, N11, N49, N07, and N06. The 9th are N75, N51, N30, N13, N14, N29, N28, N23, N33, N38, N19, N27, N34, N35, N18, N15, N10, N26, N05, N24, N22, N32, N31, N21, N03, N04, N02, N08, N20, and N01.For the yellow lines, except N12, the others distribute in the 6th, 7th, 8th and 9th group. In the 9th group, 28 yellow lines in it, which account for 93%. The others yellow lines distribute 6, 7, 8th group. The white ones almost distribute in the 3rd sub-group of 2nd group, the 3rd, 5th and 7th group, the number of lines is 21, account for 84%. The black ones, except N72 being one group, N75, N76, and N78 distribute in the 7th, 8th and 9th group respectively, the others are all in the 2nd group, which covers 57%. The red ones distribute in the 2nd sub-group of 2nd group, with no different of genetic distance.7. There is remarkable genetic difference among different colors of waxy corn inbred lines. The genetic distance of same color inbred lines is less than different ones. There is remarkable different of the least genetic distance between the inbred lines of different colors and same color lines. The 40 yellow inbred lines, the genetic distance variance range from 0.087 to 0.865, average of which is 0.632. The maximum is between N36 and N12, while the minimum is between N35 and N18, N35 and N34. For the white ones, the genetic distance variance range from 0.091 to 0.946, average of which is 0.680. The maximum is between N49 and N65, while the minimum is between N53 and N54. For 13 black ones, the genetic distance is from 0.045 to 0.895, average of which is 0.655. The maximum is between N69 and N72, while the minimum is between N77 and N78. The genetic distance between 40 yellow ones and 25 white is from 0.464 to 0.927, average of which is 0.747. The maximum is from N46 to N08, while the minimum is from N41 to N17. The genetic distance between 40 yellow ones and 13 black is from 0.517 to 0.897, average of which is 0.749. The maximum is from N72 to N30, while the minimum is from N78 to N09. The genetic difference between 25 white ones and 13 black is from 0.483 to 0.892, average of which is 0.721. The maximum is from N50 to N69, while the minimum is from N51 to N70.8. According to 22 pairs primers of SSR, the digitized fingerprint was established of 80 waxy corn inbred lines. The probability of the same map of 2 inbred lines is 8.7×10-19, so it can be adopted to identify truth from falsehood.9. The general combing ability, special combing ability and heterosis of 7 lines which randomly choice and cross combination in the field are remarkable difference. The cross combination of inbred lines N69, N51, N45 and N73 express strength heterosis. The appraised choiceness inbred lines and cross combination ones accord with the clustering analysis of genetic discrepancy, especially SSR clustering analysis.10. Through the whole experiment, during the process of the whole species genetic marker development, the morphological marker, biochemical marker, and DNA molecular marker all experienced the process from simple to complex, low reliability to high accuracy, and revealing vital phenomena to essence. It is the first to adopt 3 kinds cluster analyse of waxy corn gerrnplasm in this paper, among these three methods, the SSR molecular marker is the most reliable. |
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