Mapping of quantitative trait loci associated with chilling tolerance in maize (Zea mays L.) seedlings grown under field conditions.
The effect of low growth temperature on morpho-physiological traits of maize was investigated by the means of a QTL analysis in a segregating F(2:3) population grown under field conditions in Switzerland. Chlorophyll fluorescence parameters, leaf greenness, leaf area, shoot dry weight, and shoot nitrogen content were investigated at the seedling stage for two years. Maize was sown on two dates in each year; thus, plants sown early were exposed to low temperature, whereas those sown later developed under more favourable conditions. The main QTLs involved in the functioning of the photosynthetic apparatus at low temperature were stable across the cold environments and were also identified under controlled conditions with suboptimal temperature in a previous study. Based on the QTL analysis, relationships between chlorophyll fluorescence parameters and leaf greenness were moderate. This indicates that the extent and functioning of the photosynthetic machinery may be under different genetic control. The functioning of the photosynthetic apparatus in plants developed at low temperature in the field did not noticeably affect biomass accumulation; since there were no co-locations between QTLs for leaf area and shoot dry weight, biomass accumulation did not seem to be carbon-limited at the seedling stage under cool conditions in the field.
Jompuk
Choosak
C
Institute of Plant Sciences, Swiss Federal Institute of Technology Zurich, Universitätstrasse 2, CH-8092 Zürich, Switzerland.
Fracheboud
Yvan
Y
Stamp
Peter
P
Leipner
Jörg
J
D000064:Acclimatization; D002734:Chlorophyll / Q000378:metabolism; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D003080:Cold Temperature; D004777:Environment; D010788:Photosynthesis / Q000235:genetics; D018515:Plant Leaves / Q000502:physiology; D040641:Quantitative Trait Loci; D036226:Seedlings / Q000235:genetics* / Q000254:growth & development; D013557:Switzerland; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development
D002734:Chlorophyll