QTL Analysis Of Nutrient And N,P,K Components In Maize Under Nitrogen Stress

In this investigation,a elite hybrid maize Nongda108, it's F2:3,F2:4 families were used to identify and analyz the QTL for nutrient components under nitrogen plus (N+)and no- nitrogen plus (N-) treatments. The results were as follows:1)The genetic linkage map with 194 marker loci was constructed on maize(Zea maysL.)and covered 2100.9cM on 10 chromosomes with an average interval length of 10.82cM2)Four nutrient components in kernel:protein,starch,oil and Lysine and four nutrient components in straw: Acid Detergent Fiber(ADF),Neutral Detergent Fiber(NDF), Crude Protein(CP)and Crude Fat (CF),were measured using near infrared reflectance spectroscopy (NIRS) method.Three components of kernel and straw:N,P and K, were measured using familiar element of plant mensuration method.3)A total of 11 QTL associated with nutrient components of kernel were detected using composite interval mapping method (CIM) in F2:5 population. The result showed that 7 QTL were detected under N- condition and 4 QTL were detected under N+ condition. The QTL were lie on chromosomes 1,3,7 and 9. There were 2 QTL associated with protein,mainly concentrating on chromosomes 7 and 9,each QTL could explain over 9.50%~14.60% of phenotypic variation. There were 2 QTL associated with starch lying on chromosomes 3 and 9. Each QTL could explain over 8.77%~9.90% of phenotypic variation. There were 3 QTL associated with oil locating on chromosomes 3. Each QTL could explain over 9.82%~17.66% of phenotypic variation. There were 4 QTL associated with Lysine locating on chromosomes 1,3,7 and 9. Each QTL could explain over 8.05%~10.25% of phenotypic variation, Partially dominant ,over-dominant and additive effects played main functions in the heredity of nutrient components of kernel.4)A total of 19 QTL associated with nutrient components of straw were detected in F2:4 population. The result showed that 5 QTL were detected under N- condition and 14 QTL under N+ condition. Three QTL were identified for NDF, Each QTL could explain over 9.53 % ~12.79 % of phenotypic variation.Four QTL were identified for ADF,each QTL could explain over 8.55%~14.05% of phenotypic variation. Four QTL were identified for CF, each QTL could explain over10.03%~12.66% of phenotypic variation.Seven QTL were identified for CP, each QTL could explain over 10.26%~15.04% of phenotypic variation,Partially dominant and additive effects played main functions in the heredity of nutrient components of straw.5)A total of 22 QTL associated with N,P and K components of kernel were detected in F2:4 and F2:5 population. The result showed that 10 QTL were detected under N- condition and 12 QTL under N+ condition. Eight QTL were identified for N, Each QTL could explain over 7.80%~14.91% of phenotypic variation.Seven QTL were identified for P,each QTL could explain over 8.12%~13.03% of phenotypic variation. Seven QTL were identified for K, each QTL could explain over 8.85%~12.36% of phenotypic variation ,which indicate that partially dominant and additive effects are main gene action for N,P and K components of kernel.6)A total of 25 QTL associated with N,P and K components in straw were detected in F2:3 and F2:4 population. The result showed that 12 QTL were detected under N- condition and 13 QTL under N+ condition.Nine QTL were identified for N, Each QTL could explain over 7.30%~31.09% of phenotypic variation.Seven QTL were identified for P,each QTL could explain over 7.57%~16.65% of phenotypic variation. Nine QTL were identified for K, each QTL could explain over7.23%~32.82% of phenotypic variation,which indicate that over-dominant effect is main gene action for N,P and K components in straw.