宜机收籽粒玉米品种冠层结构、光合及灌浆脱水特性

Canopy structure, photosynthesis, grain filling, and dehydration characteristics of maize varieties suitable for grain mechanical harvesting

以京农科728等24个我国生产大面积推广的玉米品种为研究材料,比较不同类型玉米品种的冠层结构、光合及灌浆脱水特性差异,为适宜机收籽粒玉米品种选育和推广提供技术支撑。研究结果表明:(1)参试玉米品种平均机收产量、籽粒含水率、破碎率和杂质率分别为11,658.78 kg hm^(2)、24.66%、3.90%和0.83%。其中,以京2416为父本组配的京农科728等18个适宜机收籽粒玉米品种平均机收产量为11,802.70 kg hm^(2),显著高于郑单958和先玉335,分别增产7.69%和4.45%;收获时籽粒含水率均低于28%(平均为24.61%);破碎率低于5%(平均为3.42%),均达到国家机收籽粒标准。(2)以京2416为父本组配的京农科728等18个宜粒收玉米品种穗上茎叶夹角小,株型紧凑,冠层平均透光率高,冠层光分布更合理。(3)参试品种净光合速率和叶绿素含量平均为34.10μmol CO_(2)m^(-2)s^(-1)和8.91mg m^(2),其中以京2416为父本组配的18个品种净光合速率平均为35.21μmol CO_(2)m^(-2)s^(-1),较郑单958和先玉335高19.60%和6.73%;叶绿素含量平均为9.87 mg m^(2),较郑单958和先玉335高61.54%和68.43%。(4)以京2416为父本组配的18个品种灌浆速率和生理成熟后脱水速率分别平均为0.83 g 100-grain;d^(-1)和0.55%d^(-1),均显著高于郑单958和先玉335,表现为较低的收获时籽粒含水率。(5)相关分析表明,参试玉米品种产量与净光合速率、灌浆速率呈极显著正相关;净光合速率与茎叶夹角呈极显著负相关,与透光率、叶绿素含量呈极显著正相关;收获时籽粒含水率与破碎率、杂质率和生理成熟时籽粒含水率呈极显著正相关,与生理成熟后脱水速率呈极显著负相关,与灌浆速率呈显著负相关。由此可见,以京2416为父本组配的京农科728等18个玉米品种株型紧凑、冠层透光率高、光合能力强、籽粒灌浆和脱水速率高,可实现较低的籽粒含水率和较高的机收籽粒质量。

To provide technical support for the selection and popularization of corn varieties suitable for mechanized grain harvest,the canopy structure,photosynthetic characteristics,and mechanical harvesting characteristics of different types of maize varieties were compared with 24 maize varieties including Jingnongke 728 produced and widely promoted in China.The results showed that:(1) The average yield,moisture content,broken rate and impurity content at harvest of the tested varieties were 11,658.78 kg hm^(2),24.66%,3.90%,and 0.83%.The average yield of 18 suitable machine harvesting varieties such as Jingnongke 728 with Jing2416 as male parent was 11,802.70 kg hm^(2),which was significantly higher by 7.69%and 4.45%than those of Zhengdan 958 and Xianyu 335,respectively.The grain moisture content at harvest was lower than 28%(average 24.61%);The average broken rate was less than 5%(average 3.42%),reaching the national standard of machine harvested grain.(2) 18 maize varieties suitable for grain mechanical harvesting such as Jingnongke 728 with Jing 2416 as male parent had small angle between stem and leaf,compact plant type,high average light transmittance and more reasonable light distribution.(3) The average net photosynthetic rate and chlorophyll content of the tested maize varieties were 34.10μmol CO_(2)m^(-2)s^(-1) and 8.91 mg m^(2).The average net photosynthetic rate of the 18 maize varieties suitable for machine harvesting with Jing 2416 as male parent was 35.21μmol CO_(2)m^(-2)s^(-1),which was 19.60%and 6.73%higher than Zhengdan 958 and Xianyu 335.The average chlorophyll content was 9.87 mg m^(2),which was 61.54%and 68.43%higher than Zhengdan 958 and Xianyu 335.(4) The average grain filling rate and dehydration rate after physiological maturity of 18 varieties with Jing 2416 as male parent were 0.83 g 100 grain;d^(-1) and 0.55%d^(-1),respectively,which were significantly higher than those of Zhengdan 958 and Xianyu 335,showing a lower grain moisture content at harvest.(5) Correlation analysis revealed that the yield of the tested varieties was significantly positively correlated with net photosynthetic rate and grain filling rate.The net photosynthetic rate was negatively correlated with the angle between stem and leaf,and positively correlated with light transmittance and chlorophyll content.Grain moisture content at harvest was significantly positively correlated with breakage rate,impurity content and grain moisture content after physiological maturity,negatively correlated with dehydration rate after physiological maturity,and negatively correlated with grain filling rate.In conclusion,maize varieties suitable for mechanical harvesting under the condition of high planting density should have compact plant type,high canopy light transmittance,strong photosynthetic capacity,high grain filling,and dehydration rate,which could lead to achieve lower grain moisture content and higher yield.