| Maize is one of the main grain crops in our country,and the important raw material in chemical,fuel and pharmaceutical.Heilongjiang Province is one of the important maize production bases in China,due to the less effective accumulated temperature,short frost-free period and frequent early frost,the spring maize grain moisture content at harvest was too high,which affect the mechanical harvest,decreased the quality of grain and yield,and lead to the maize market competitiveness.Therefore,in this study Xianyu 335 and Xinxin 2 were used as experimental material,spraying on 25 days after flowering with three kinds of chemical regulators,thidiazuron,ethephon and thidiazuron-ethephon compound,spraying water as control(CK),and test the grian moisture content,grain filling characteristics,hormone levels,leaf osmotic adjustment substances and yield,the purpose is to investigate the effect of thidiazuron-ethephon compound on grain dehydration,grain filling,yield and quality,and its regulatory mechanism.The results showed that:(1)The compound of thidiazuron and ethephon can accelerate the rate of grain dehydration and decreased the kernel moisture content of Xianyu 335 and Xinxin 2.The experiments showed that the water content of grain is very significantly positively correlated with the water content of the cobs and bracts(P < 0.01),and significantly positively correlated with three-ear-leaves(P < 0.05).(2)The compound of thidiazuron and ethephon decreased duration of the rapid increase period and the moderate increase period of grain filling stage,increase the average filling rate and grain weight.After thidiazuron-ethephon treatment,the continuous time of the rapid increase period in Xianyu 335 and Xinxin 2 were shortened by 3d and 1d,respectively,and the average rates were increased by 19.10% and 10.99%,respectively,the grain weight increased by 1.18% and 4.22%,the continuous time of the moderate increase period was shortened by 3d and 1d,the average rate increased by 19.35% and 9.38% respectively,and the grain weight increased by 1.17% and 4.17%,respectively.(3)The compound of thidiazuron and ethephon significantly improve IAA(indole-3-acetic acid),and GA(gibberellin acid)content in grains at late grain filling stage,reduce the content of ABA(abscisic acid)and CTK(cytokinin).At the same time,the ratio of IAA and ABA,GA and ABA in grain filling stage was significantly increased,and the ratio of CTK and IAA,CTK and GA was decreased.And the ratios of CTK and ABA,GA and IAA were less affected.The content of ABA and CTK in grain of spring maize was negatively correlated with the rate of rapid growth of grain filling.(4)With the treatment of thiobenzol-ethylene compound,the activity of SOD,POD,CAT and SPAD value of maize leaves were decreased,which accelerated the aging of the leaves in the late maize filling.The total growth period of Xianyu 335 and Xinxin 2 were shortened by 6d and 5d,respectively,indicating that thiobenzene and ethylene recombination had a good ripening effect,which could avoid the harm of early frost in Heilongjiang Province.(5)The compound of thidiazuron and ethephon can increase maize grain weight and increase yield.After the treatment of thidiazuron-ethephon on Xianyu 335 and Xinxin 2,the 100-grain weight increased by 1.43 g and 1.60 g,respectively,and the yield increased by 13.44% and 10.50%,respectively.The impact on maize quality is not significant. |
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