QTL Analysis Of Nutrient Components In Maize Under Nitrogen Stress

In this investigation,a elite hybrid maize Nongda108,extended about 2.7 million hectares per year during 2001-2004 in China and it's F2:3, it's F2:4 families were used to identify and analyz the QTL for nutrient components under high and low nitrogen treatments in Zhengzhou and Xinzheng. The results were as follows:1)The genetic linkage map with 189 marker loci was constructed on maize(Zea maysL.).The map covered 2058.1cM on 10 chromosomes with an average interval length of 10.89cM2)Three nutrient components of kernel,protein,starch and oil and four nutrient components of straw: Acid Detergent Fiber(ADF),Neutral Detergent Fiber(NDF), Crude Protein(CP)and Crude Fat (CF),were measured using near infrared reflectance spectroscopy (MRS) method.3)A total of 30 QTL associated with nutrient components of kernel were detected using composite interval mapping method (CIM) in F_2:4 population. The result showed that 12 QTL were detected under low-N condition and 18 QTL were detected under high-N condition. The QTL were lie on chromosomes 1,2,3,4,7 and 9. There were 11 QTL associated with protein,mainly concentrating on chromosomes 1 and 3,each QTL could explain over 8.97%～34.31% of phenotypic variation. there were 10 QTL associated with starch lying on chromosomes 1,3,4,7 and 9. Each QTL could explain over 7.93 %～20.76% of phenotypic variation. There were 9 QTL associated with oil locating on chromosomes 2,3,4,7 and 9. Each QTL could explain over 7.69%～16.12% of phenotypic variation.The result of gene action showed that 13 QTL are additive and account for 43.33%;11 QTL are partial dominant and account for 36.67%; 3 QTL are dominant and account for 10.00%; 3 QTL are overdominant and account for 10.00%,which indicate that additive effect and partial dominance are main gene action for nutrient components.3) A total of 37 QTL associated with nutrient components of straw were detected in F_2:3 population. The result showed that 17 QTL were detected under low-N condition and 20 QTL under high-N condition. 10 QTL were identified for ADF, which located on chromosomes 2,4,6,9 and 10,each QTL could explain over 8.54%～17.93% of phenotypic variation. 7 QTL were identified for NDF, which located on chromosomes 3,4,6 and 10,Each QTL could explain over 9.28%～20.51% of phenotypic variation. 12 QTL were identified for CP,which located on chromosomes1,3,5,8,9 and 10,each QTL could explain over 7.52%～13.55% of phenotypic variation. 8 QTL were identified for CF,which located on chromosomes 3,4,5,6 and 10,each QTL could explain over 9.71%～16.05% of phenotypic variation.The result of gene action showed that 12 QTL are additive and account for...