The objective of this study was to assess the chlorophyll content of corn lines at different vegetative stages and the diversity between them. The study was conducted in the experimental field of the Roque Institute o...The objective of this study was to assess the chlorophyll content of corn lines at different vegetative stages and the diversity between them. The study was conducted in the experimental field of the Roque Institute of Technology (ITR) located in Roque, Celaya, Guanajuato, Mexico. We used 32 corn lines from CIMMYT and four lines from the breeding program of the ITR. The evaluation was conducted in the spring-summer cycle of 2014 at two planting dates. We used a completely randomized block design with three replications. The experimental unit consisted of two rows of five linear meters with a distance of 0.75 meters between rows. Chlorophyll was measured at six different stages: V6, VT, R3, R4, R5 and MF. The agronomic variables recorded were: PH, CH, LAC, LBC, FF, MF, PM, CC, CL, DC, RC, KR and GY. The results of the analysis of variance showed significant differences between lines, dates and their interaction. On average, 18 lines were found with chlorophyll concentrations above 51 SPAD units in the two environments. This indicated that these materials had a high potential for field performance. Using cluster analysis UPGMA method, we identified seven groups for chlorophyll and eight groups for agronomic characteristics for a breeding program. The groups were associated to the homogeneous characteristics of each variable.展开更多
The purpose of this study was to evaluate the relationship of tetrazolium salt testing to common indicators(milk line,black layer,dry matter)used to determine corn seed physiological maturity.The seeds used were the h...The purpose of this study was to evaluate the relationship of tetrazolium salt testing to common indicators(milk line,black layer,dry matter)used to determine corn seed physiological maturity.The seeds used were the hybrids Pioneer 4285 and Dow 2B587.These hybrids were harvested 40 days after polinization(DAP),with 4-day intervals until 68 DAP.The harvested seeds were evaluated for viability and vigor(germination test,accelerated aging test and cold test).The parameters used to determine the physiological seed’s maturity were the black layer,the milk line,the seed dry matter,seed water content and the evaluation of seed tissues using the tetrazolium salt to evaluate the endosperm cells.The germination of both materials was greater than 95%and there was no difference between harvest times.Corn seed physiological maturity(PM)was identified at 56 DAP for P4285(F2)and between 48 and 56 DAP for 2B587(F2).The maximum vigor was detected by accelerated aging tests and cold tests before PM for the two genotypes.The activity of endosperm cells is related to the other PM indicators(milk line,black layer,dry matter and water content).The transport of nutrients from plant to the seed ceases at seed physiological maturity.Use of tetrazolium salt allows identifying cell death of the basal region and this parameter corresponds to the others evaluated,thus demonstrating that the tetrazolium salt is effective for corn seed physiological maturity characterization.展开更多
本文旨在探讨以不同波段组合垂直植被指数所建立的高光谱模型对玉米叶面积指数（Leaf Area Index，LAI）的反演精度。在不同水肥耦合作用条件下，实测玉米冠层的高光谱反射率与叶面积指数数据以及裸土的高光谱反射率数据，在高光谱红光...本文旨在探讨以不同波段组合垂直植被指数所建立的高光谱模型对玉米叶面积指数（Leaf Area Index，LAI）的反演精度。在不同水肥耦合作用条件下，实测玉米冠层的高光谱反射率与叶面积指数数据以及裸土的高光谱反射率数据，在高光谱红光波段（631～760nm）与近红外波段（760～1050nm）逐波段构建土壤线，并在此基础上构建垂直植被指数（Perpendieolar Vegetation Index，PVI），找出与LAI具有最佳相关性波段组合PVI，建立玉米LAI估算模型。结果显示，采样波段间隔越窄，反演精度越高，在采样波段间隔1．4nm的PVI（R677，R918）反演2004年的玉米LAI模型中，最佳回归方程是指数函数，精度达91．1％，标准差为0．1997，RMSE=0．0399，通过了0．01极显著验证。采用高光谱数据构建的PVI植被指数对玉米LAI的估算可以取得较高的精度。展开更多
文摘The objective of this study was to assess the chlorophyll content of corn lines at different vegetative stages and the diversity between them. The study was conducted in the experimental field of the Roque Institute of Technology (ITR) located in Roque, Celaya, Guanajuato, Mexico. We used 32 corn lines from CIMMYT and four lines from the breeding program of the ITR. The evaluation was conducted in the spring-summer cycle of 2014 at two planting dates. We used a completely randomized block design with three replications. The experimental unit consisted of two rows of five linear meters with a distance of 0.75 meters between rows. Chlorophyll was measured at six different stages: V6, VT, R3, R4, R5 and MF. The agronomic variables recorded were: PH, CH, LAC, LBC, FF, MF, PM, CC, CL, DC, RC, KR and GY. The results of the analysis of variance showed significant differences between lines, dates and their interaction. On average, 18 lines were found with chlorophyll concentrations above 51 SPAD units in the two environments. This indicated that these materials had a high potential for field performance. Using cluster analysis UPGMA method, we identified seven groups for chlorophyll and eight groups for agronomic characteristics for a breeding program. The groups were associated to the homogeneous characteristics of each variable.
文摘The purpose of this study was to evaluate the relationship of tetrazolium salt testing to common indicators(milk line,black layer,dry matter)used to determine corn seed physiological maturity.The seeds used were the hybrids Pioneer 4285 and Dow 2B587.These hybrids were harvested 40 days after polinization(DAP),with 4-day intervals until 68 DAP.The harvested seeds were evaluated for viability and vigor(germination test,accelerated aging test and cold test).The parameters used to determine the physiological seed’s maturity were the black layer,the milk line,the seed dry matter,seed water content and the evaluation of seed tissues using the tetrazolium salt to evaluate the endosperm cells.The germination of both materials was greater than 95%and there was no difference between harvest times.Corn seed physiological maturity(PM)was identified at 56 DAP for P4285(F2)and between 48 and 56 DAP for 2B587(F2).The maximum vigor was detected by accelerated aging tests and cold tests before PM for the two genotypes.The activity of endosperm cells is related to the other PM indicators(milk line,black layer,dry matter and water content).The transport of nutrients from plant to the seed ceases at seed physiological maturity.Use of tetrazolium salt allows identifying cell death of the basal region and this parameter corresponds to the others evaluated,thus demonstrating that the tetrazolium salt is effective for corn seed physiological maturity characterization.
文摘本文旨在探讨以不同波段组合垂直植被指数所建立的高光谱模型对玉米叶面积指数（Leaf Area Index，LAI）的反演精度。在不同水肥耦合作用条件下，实测玉米冠层的高光谱反射率与叶面积指数数据以及裸土的高光谱反射率数据，在高光谱红光波段（631～760nm）与近红外波段（760～1050nm）逐波段构建土壤线，并在此基础上构建垂直植被指数（Perpendieolar Vegetation Index，PVI），找出与LAI具有最佳相关性波段组合PVI，建立玉米LAI估算模型。结果显示，采样波段间隔越窄，反演精度越高，在采样波段间隔1．4nm的PVI（R677，R918）反演2004年的玉米LAI模型中，最佳回归方程是指数函数，精度达91．1％，标准差为0．1997，RMSE=0．0399，通过了0．01极显著验证。采用高光谱数据构建的PVI植被指数对玉米LAI的估算可以取得较高的精度。
