Effects Of Potassium Application Rate On The Growth And Yield And Quality Of New Strains Of Flue-cured Tobacco Genotypes With High Potassium Efficiency

In order to investigate the effects of potassium application rate on the growth and yield and quality of new strains of flue-cured tobacco genotypes with high potassium efficiency. Field experiments with flue-cured tobacco K326(CK)and GK2,GK8(flue-cured tobacco genotypes with high potassium efficiency)were conducted in tobacco cultivation base of Hunan Agricultural University in 2009.The experiments analyzed the difference of growth period, agronomical traits, dry matter accumulation of tobacco, physiological and biochemical characteristics, economic characteristics of tobacco and chemical composition of cured leaves in different potassium application rate. The results showed that:1. The growth period of new strains of flue-cured tobacco genotypes with high potassium efficiency was obviously affected by potassium application. The tobacco without potassium fertilizer grew slowly and the bud appeared later; The symptoms of potassium deficiency was obvious,the leaves yellowing faster in late and the field growth period was Significantly shortened; The field growth period of the GK2 and GK8 slightly earlier than the K326.2. Potassium application could significantly improve the biological properties of the new strains, promote the increase of plant height, stem thickness, leaf size and leaf number. Growing tobacco looked basically the same under different potassium levels in the rosette stage.The tobacco plants grew best under the potassium level of 240 kg/hm2 in the vigorous growing period, in different genotypes showed:GK8>GK2>K326。3. The dry matter accumulation of the new strains roots, stems and leaves increased with potassium application rate increased. Amount of dry matter accumulation in different organs showed:leaf>stem>root, between the different potassium levels showed: T3>T2>T1. T3compared with T1, the dry matter accumulation of leaves of K326,GK2 and GK8 respectively increased by 35.93%,36.45%,42.71% in the mature stage. In different genotypes showed:GK8>GK2>K326。4. Potassium application could promote the ability of chlorophyll synthesis, increase the activity of NR, adjust the activity of POD to some extent.5. Economic characteristics of the new strains significantly affected by potassium application. Potassium fertilizer could increase the yield, output and proportion of upper-middle of the new strains. The new strains in the highest yield under the potassium level of 240 kg/hm2 and K326,GK2,GK8 respectively reached 2353.02 kg/hm2,2422.57 kg/hm2,2478.09 kg/hm2. The tobacco production of K326, GK2 and GK8 under the potassium level of 240 kg/hm2 were higher than the treatment without potassium fertilizer to 69.92%,64.30%,69.97%. The proportion of mid-upper leaves of K326 achieved the best performance of 88.14%.6. Determination of chemical composition of cured leaves showed that the content of total sugar, reducing sugar, potassium of the new strains increased with potassium application rate increased, the content of nitrogen, nicotine, chloride of the new strains decreased with potassium application rate increased; The potassium content of K326,GK2 and GK8 respectively reached 2.05%,2.46%,2.37%;The ratio of reducing sugar and nicotine, potassium and chloride, total sugar and nitrogen were all proper; The quality of tobacco is the best under the potassium level of 240 kg/hm2.