The Characters Of Agronomic Traits On Low-density And High-density Planting Of Wheat Cultivars (Lines) From Huanghuai Southern Region

The difference of wheat agronomic traits between the low-density planting and the high-density planting can provide evidences for individual selection of wheat breeding generation.One hundred and eighty-seven wheat lines from Huanghuai Southern winter wheat region were planted in Zhengzhou Science and Education Experimental Garden of Henan Agricultural University in 2014-2015,the fourteen main agronomic traits were identificated at two conditions of low-density and high-density planting,and the differences were analyzed.The results were as follows:1.Extremely significantly difference existed in heading stage,flowering stage,plant height,flag leaf length,flag leaf width,spike length,single spike weight,grain number per spike,fertile and infertile spikelet number between the low and high density planting mode,while no significant difference was found in neck length,internode length under spike,thousand grain weight and flag leaf angle.Compared with low-density planting,the materials planted in high-density mode averagely headed and flowered 1.43 days and 0.82 days,respectively.Meanwhile,plant height,neck length respectively increased by 5.6 cm and 0.4 cm along with the slightly magnified flag leaf angle.In contrast,the internode length under spike,flag leaf length,flag leaf width,spike length averagely reduced by 0.29 cm,1.45 cm,0.13 cm,0.31 cm,respectively.The fertile spikelet number reduced by 0.55,whereas the infertile spikelet number increased by 0.42.In addition,grains per spike,thousand grain weights,single spike weight averagely reduced by 5.41 g,0.32 g,0.35 g,respectively.2.All of the 14 agronomic traits significantly positively correlated with each other between low and high density planting mode,while the correlation coefficient varied greatly as to each character.From specific point of view,the correlation index of heading stage,flowering stage and plant height reach above 0.9,thus the performance of varieties under low density planting were consistent with materials under the higher density environment.It is more accurately to predict the character performance under high density environment by low density planting model with the help of regression equation method.In contrast,the correlation coefficient of flag leaf width,grain number per spike and thousand grain weights didn't reach above 0.6,thus poor consistency were seen for the agronomic characters under two environments.Other correlation coefficients of the traits were at the middle level.3.There were highly significantly regression relationships between yield characters in high density planting and plant height and single spike weight in low density,thus higher plant height and heavier for plants under low density planting were not conducive to the yield improvement.There were extremely significant regression relationships between single panicle weight under high density planting and internode length under spike,flag leaf length,single spike weight in low density mode,thus longer internode length under spike,shorter flag leaf and lighter single spike weight in low density mode were all not contributed to the improvement of single spike weight under high density planting.There were extremely significant regression relationships between thousand grain weight under high density planting and ears per plant,grain number per spike,thousand grain weight,single spike weight under low density planting,while a nearly significantly relationship with flag leaf length.Thus,too much ears per plant,grain number,lower grain and single panicle weight under low density planting plant were not helpful to the improvement of grain number under high density planting.There were extremely significant regression relationships between grain number under high density planting and spike length,grain weight and single spike weight under low density planting,while a significant regression relationship with grain number per spike under low density planting.Thus shorter flag leaf,smaller grain number per spike,higher thousand grain weights,lighter single spike weight under low density planting could not easily get access to the improvement of grain number per spike.There was a highly significant regression relationship between acres spikes under high density planting and flag leaf length,ears per plant,single spike weight under low density planting,while a significant regression relationship with sterile number of spikelets under low density planting.Thus,longer flag leaf,less spikes per plant and heavier single spike weight under low density planting were not advantage for the increasing of acres panicles in high density planting mode.