Quantitative genetic analysis of flowering time, leaf number and photoperiod sensitivity in maize (Zea mays L.)

Photoperiod sensitivity is a major difficulty of broadening the resources of breeding germplasms and widening the planting area of varieties in maize. The objective of this study was to dissect the quantitative genetic control of days to pollen shed (DPS), days to silking (DS), anthesis-silking interval (ASI), LNB (the leaf number below the top ear), LN (the total leaf number), and photoperiod sensitivity index (PSIs) of these traits into the main-effect quantitative trait loci (QTL) in an F 2 population consisting of 232 F 2:3 lines from the cross between HZ32 (low sensitive to photoperiod) and Huangzao4 (high sensitive to photoperiod). DPS, DS, LNB and LN of the F 2:3 families and parents were investigated in two locations, Beijing (with a longer photoperiod regime, east longitude 117, northern latitude 41) and Wuhan (with a shorter photoperiod regime, east longitude 113, northern latitude 29) in 2007. Further QTL analysis resolved the genetic components of DPS, DS, ASI, LNB and LN into the main-effect QTLs and gene × environment interactions. A total of fifty-nine QTLs for all PS related traits were found in the two photoperiod environments, twenty-two QTLs for PSIs and twenty-two QTLs for QTL × environment were included, respectively. Some important genes associated with photoperiod response and flowering time are found in the regions. The known QTLs and the implications of the results for maize breeding have been discussed.