Abstract
BackgroundAn understanding of the genetic determinism of photoperiod response of flowering is a prerequisite for the successful exchange of germplasm across different latitudes. In order to contribute to resolve the genetic basis of photoperiod sensitivity in maize, a set of 201 recombinant inbred lines (RIL), derived from a temperate and tropical inbred line cross were evaluated in 5 field trials spread in short- and long-day environments.Methodology/Principal FindingsFirstly, QTL analyses for flowering time and photoperiod sensitivity in maize were conducted in individual photoperiod environments separately, and then, the total genetic effect was partitioned into additive effect (A) and additive-by-environment interaction effect (AE) by using a mixed-model-based composite interval mapping (MCIM) method.Conclusions/SignificanceSeven putative QTL were found associated with DPS thermal time based on the data estimated in individual environments. Nine putative QTL were found associated with DPS thermal time across environments and six of them showed significant QTL×enviroment (QE) interactions. Three QTL for photoperiod sensitivity were identified on chromosome 4, 9 and 10, which had the similar position to QTL for DPS thermal time in the two long-day environment. The major photoperiod sensitive loci qDPS10 responded to both short and long-day photoperiod environments and had opposite effects in different photoperiod environment. The QTL qDPS3, which had the greatest additive effect exclusively in the short-day environment, were photoperiod independent and should be classified in autonomous promotion pathway.
Highlights
Flowering time is known to be an important reproductive characteristic of agronomic interest and plays a principal role in the geographical adaptability of plants, the expression of which highly depends on environmental conditions
We present a novel genetic investigation of photoperiod response in maize in three photoperiod environments, using a mixed-model-based composite interval mapping (MCIM) method, based on a recombinant inbred line (RIL) population derived from a temperate6tropical cross
Thermal time from sowing to days to pollen shed for CML288 grown in the long day environments of Henan and Beijing increased by 61.74% and 86.23%, respectively, compared with grown in short day conditions of Sanya, while Huangzao4 increased by only 24.02% and 35.81%, respectively
Summary
Flowering time is known to be an important reproductive characteristic of agronomic interest and plays a principal role in the geographical adaptability of plants, the expression of which highly depends on environmental conditions. Photoperiod sensitivity results in plants not adapting to environments outside the ecogeographical ranges of their wild ancestors and is the major obstacle of exchange between different geographical regions. An understanding of the genetic determinism of flowering time in different photoperiod environment is a prerequisite for the usage of tropical maize germplasm in temperate areas. An understanding of the genetic determinism of photoperiod response of flowering is a prerequisite for the successful exchange of germplasm across different latitudes. In order to contribute to resolve the genetic basis of photoperiod sensitivity in maize, a set of 201 recombinant inbred lines (RIL), derived from a temperate and tropical inbred line cross were evaluated in 5 field trials spread in short- and long-day environments
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