A Study Of Grain Filling And Dehydration Of Rate For Dilfferent Periods Of Maize Single-cross Hybrids And Their Parents In China

It was slow in the rate of Grain filling and natural dehydration of maize in field after physiologicalmaturity,which were important limiting factors to corn yield and quality and increase storage andprocessing costs in the area of north maize region. It is necessary to study the trend of grain filling anddehydration rate of hybrids and inbred lines in different periods for the elections about faster grainfilling and dehydration rate of single cross hybrids. It is also significant to improve the quality of thecorn. Twenty hybrids and their32parents in different period utilized widely representative in Chinawere chose as the materials. By split plot design, it was researched for the changes in maize grain kernelweight, moisture content, grain filling and dehydration rate, the correlation between grain qualityingredients with grain filling and dehydration rate, analysis of the genetic effects of grain filling anddehydration. The main results were as follows:Grain filling rate was a single peak curve, the peak usually appear15-20days after pollination; thedehydration rate showed the trend of continuous downward in the physiological maturity and the upsand downs of wave changes after physiological maturity; It exists significant differences in the grainfilling and dehydration rate of hybrids and inbred lines on a different occasion and different samplingtime；Different densities of single cross hybrids and inbred lines have no difference in the average grainfilling and dehydration rate. Density does not affect the appearance time of peak filling rate.Hybrids in recent years has higher moisture content than early varieties at physiological maturityand harvest, and the dry matter accumulation in the rate and duration increased compared with the earlyvarieties; there are obvious differences in water content and dry matter accumulation of the differentgroups of inbred lines, Lancaster and Tangsipingtou groups has higher water content than the othergroups, P and Reid group has higher rate and longer duration of dry matter accumulation than the othergroups; it exists significant differences in the dehydration rate of different hybrids after physiologicalmaturity. Some varieties has fast dehydration rate in the early periods, such as Benyu9and Yandan14. Inrecent years, hybrids except Xianyu335has very low dehydration rate.The relationship of the grain ingredients, grain filling and duration rate indicated that⑴grainfilling rate has very significant negative correlation with grain fresh weight and dry weight,⑵there is apositive correlation between grain filling rate and dehydration rate,⑶there is a negative correlationbetween starch and protein, oil,⑷t hereis no obvious correlation in grain ingredient with grain fillingand duration rate.The inheritance of maize grain filling and dehydration rate fitted the additive-dominant model, it ishigh for the proportion of the dominant effect and broad sense heritability of the grain filling rate, so itis not suitable to select in early generation; it is high for the proportion of the additive effect and broadsense heritability of grain dehydration rate, so it is effective to select this trait within the group. Theresults of this study provide methods and theoretical basis to breed rapid dehydration of maize varieties.