QTL Mapping for Controlling Days to Pollen Shed under Different Nitrogen Regimes in Maize

Nitrogen (N) deficiency affects severely many metabolic pathways and physiological progresses during maize (Zea mays L.) growing stage, and change of days to pollen shed (DPS) is one of the most serious consequences. To realize the genetic basis of DPS, a recombinant inbred line (RIL) population from the cross between Mo17 and Huangzao4 was used to identify the quantitative trait loci (QTLs) controlling DPS under two N regimes. As a result, 2 QTLs were detected, of which the QTL identified under both N regimes was quite near to the marker Nc134, with 0 centiMorgan (cM) of mapping distance between them, it could account for 15.36% and 10.39% of phenotypic variance under high and low N regimes respectively, and could make maize flower with ahead of time about 1 d duo to its additive effect. The other QTL, identified only under low N regime, was close to marker Bnlg1129 with 8.6 cM of maping distance between them, could explain 12.39% of phenotypic variance and increase DPS for 0.8 d owing to its additive effect. These results are beneficial for understanding the genetic basis of DPS in maize.