Abstract
For elucidating the genetic basis of N, P and K contents in kernels and stalks in maize under different nitrogen supply condition, a set of 203 F2: 4 / F2: 5 family lines, derived from an elite maize hybrid Nongda108, were tested under nitrogen plus (N+) and no nitrogen plus (N-) treatments in the field over two years, and a genetic linkage map was constructed with 199 SSR molecular markers, covered 2100.9 cm for 10 chromosomes with an average interval length of 10.82 cm. The results showed that low N stress not only affected N content in maize kernels and stalks, but also affected the absorption and transportation of P and K contents in some degree. A total of 34 quantitative trait locus (QTL) including 15 QTLs in kernels and 19 QTLs in stalks for N, P, K content were identified by means of the composite interval mapping method (CIM), of which, 13, 9 and 12 QTLs detected for N, P, K content, respectively. Each QTL could explain the variance of phenotype ranged in turn from 7.30 to 31.09%, 7.57 to 14.3% and 8.11 to 32.82% for three main mineral elements content. The QTL qNC4c, qPC9b, qKC10b as well as qNC4b, qPC5b, qKC6a were main contributing QTL for N, P, K contents in kernels and stalks. Out of these QTLs detected for N, P, K contents in kernels and stalks, the results also implied that the loci derived from Huang C played important roles in N, P, K absorption, while the loci from Xu178 played marked roles in N, P, K transportation from stalks to grains.
Key words: Maize, low nitrogen stress, N, P, K content, quantitative trait locus (QTL), analysis.
