The QTL Analysis Of Kernel Dehydration Rate In Maize

Maize(Zea mays L.)is the important food,industrial materials,feed and economic crop in China.As one of the most important crops,it plays an leading role in global food security,feed and bio-energy.Maize mechanization will be the development trend in China.There is a problem in maize production that kernel mechanical harvest is restricted by high kernel moisture content.High kernel moisture content not only can increase breakage rate,but also cause the kernel mildew and early germination.Planting fast-dehydration rate varieties is the main way to reduce the kernel moisture content.So kernel dry down rate is the important goal in maize breeding.In this study,four maize varieties were used to measure the moisture reading in ear,husk,kernel and cob using oven method and moisture meter reading method.Comparing the date of two methods to develop a tool that could be used to measure kernel moisture with moisture meter.After that,242 maize recombinant inbred lines derived from a cross between RA and M53 were used as materials.We measured the kernel moisture content in 5th week and 8th week after silking stage during two consecutive years,which can be used to select the inbred lines with fast-dehydration rate and to locate the QTL for dehydration rate.The main results were summarized as followed:1.Four maize varieties ZD958,XY335,SY29,TY88 were used to measure the moisture content of kernel with oven method and moisture meter reading method.Then calculate the dehydration rate and filling rate.The results show that moisture content has significant differences between the varieties.Dehydration rate and filling rate have significant related.The regression analysis of total ear moisture readings(measured with moisture meter reading method)and kernel moisture(measured with oven method)shows that total ear moisture reading could be used to predict kernel moisture,using the power function y=0.59X1.095(R2=0.958).2.242 maize recombinant inbred lines were used as materials.We measured the moisture content of kernel during two consecutive years,based on the standard formula.Seven inbred lines which have low kernel moisture content and short silking stage were selected.The seven inbred lines included:HQM44,HQM65,HQM181,HQM190,HQM192,HQM194,HQM233.3.242 maize recombinant inbred lines were evaluated for dehydration rate.QTL mapping was performed using composite interval mapping.15 additive QTL are located on lth,3th,4th,5th and 6th chromosome respectively.LOD value is 2.03-3.63,which can explain phenotypic variation 1.07%-10.69%.