| In this paper,super-high yield corns(Xianyu335 and Zhengdan958) and common corns (Nongda364 and Sanbei9) were selected for studies,whose yield-forming physiological process and regulation of dry matter accumulation were studied.The field trials were conducted at the Experimental Station of Jilin Agricultural University(Changchun,China) and Hongshi,Huadian city(Jilin,China) in 2006 and 2007,and were adopted randomized block design.The plots were randomized with three replicates in all field trials.As a result,LA,LAI,LAD and Chlorophyll content were determined per 20 days at the beginning of the seedling stage.The dry matter accumulation of different organ was evaluated at the main growth periods.In addition,the fresh weight,dry weight,volume and the rate of grain-filling of corn kernel were determined after grain-filling stage.And the yield complications were determined in mature stage.A series of results were as follows:1.There were significant differences in the yield and economic coefficient between super-high yield and common corns(p≤0.05):The order was as follows: Xianyu335＞Zhengdan958＞Nongda364＞Sanbei9.2.There was higher rate of grain-filling and the longer duration in super-yield corns compared to the common corns.The duration time of high grain-filling of Xianyu335 and Zhengdan958 was 56 and 48 days,respectively.However,that of Nongda364 and Sanbei9 was 39 days.In addition,there was significant correlation between the grain weight and the rate and the duration time of grain-filling.3.There was higher rate of dry matter accumulation in super-high yield corns compared to common corns.The order was that Xianyu335＞Zhengdan958＞Nongda364＞Sanbei9.The contribution of dry matter was different in different growth stage.During the whole growth periods,that of Xianyu335 was the highest,then Zhengdan958,and there was the lowest contribution in Sanbei9.4.The largest dry weight of nutrient organ(bract,leaf and stem-sheath) occurred after the teaseling stage.The rate of dry matter on corn bract,leaf and stem sheath transported to seed varied with the corn varieties,which of super-high yield(Xianyu335) was the highest and of Sanbei9 was the lowest.5.The contribution of the dry matter accumulation(bract,leaf and stem-sheath) to grain varied with the types of corn varieties.The contribution of bract to kernel was the lowest in super-high yield(Xianyu335) but that of leaf and stem-sheath was the highest in Xianyu335.6.The LAI and LAD of super-high yield corns were higher compared to the common corns under group condition.However,the higher or lower LAI was disadvantage to the ratio (grain/leaf).Only the eligible LAI could coordinate the source-sink relation to achieve high yield of corns.The linear regression analysis indicated that there was positive correlation between LAI,LAD and grain yield,grain per ear,yet no significant correlation with 100-grain weight.7.There was significant difference in the output percent of stem-sheath store matter among different corn varieties(p≤0.01).The order was as follows:Sanbei9＞Nongda364＞Zhengdan958＞Xianyu335.There was negative correlation between the stem-sheath store matter and yield(its components).The result showed that super-high yield corns had many characteristics,such as the higher dry matter accumulation,the lower output percent of stem-sheath store matter,the higher rate and longer duration of grain-filling,the higher LAI and LAD and the higher rate of dry matter on corn bract and stem-sheath transported to seed.The purpose of this study was thus to provide theories for the high quality and yield corn cultivation and to establish the foundation to the super-high yield cultivation in Jilin Province. |
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