Analysis of Differences in Potassium Content among Tobacco Germplasm and Screening of Field Identification Indicators

【Objective】In this paper, the screening of field identification indicators of potassium content in tobacco leaves was explored and the difference of potassium content among tobacco germplasms was analyzed in order to select suitable identification indicators and establish a mathematical evaluation model.【Method】31 tobacco germplasms were treated in field experiments. 11 morphological characteristic indicators, such as plant height（x1）, stem girth（x2）, intermodal distance（x3）, leaf number（x4）, maximum leaf length（x5）, maximum leaf width（x6）, angle of lateral vto midrib（x7）, angle between stem and leaf（x8）, corolla length（x9）, corolla diameter（x10）and calyx length （x11）were investigated and hierarchical cluster analysis, principal component analysis, factor analysis and multiple stepwise regression analysis were used to comprehensively evaluate the potassium content in tobacco leaves. 【Result】 Results revealed that 31 tobacco germplasm were clustered into high potassium germplasm, medium potassium germplasm and low potassium germplasm by cluster analysis. 11 single indexes were transformed into 5 independent comprehensive indicators through principal component analysis, which represented 84.624% of the whole data of the traits related to tobacco potassium content. And a mathematical evaluation model of potassium content in tobacco leaves was established by multiple stepwise regression analysis, i.e.y=-1.699+0.041 x5+0.831 x10（R2=0.9602）,with an accuracy of 89.66%.【Conclusion】 Leaf length（x5）and corolla diameter（x10）reflected the potassium content of tobacco leaves significantly and could be used as field identification indicators for the potassium content of tobacco leaves.