Studies On Technique Of Improving Virus-free Potato Yield And Selenium Content

Potato is one of the important grain crops besides the grain kind of crop of standing grain.It is full of starch,carbohydrate,protein,mineral salt and vitamina,its nutrition value is high.It is one kind of grain crops with high yield,and is also the fine vegetable that supplied for the market.Its characteristics include high yield,broad use,strong adptability,storagble, convenient transportation.Se is one of micro-elements which are necessary for human body.Researching the role of the selenium-rich preparation playing in potato production and popularizing selenium-rich green potato culture technology,can raise potato yield,increase the peasant's economic income. The experiment were carried out with field trial,studied the influence of virus-free potato breeds,planting density,NP combinations on potato yield. Through the analysis of potato tube yield and biological character,we have also explored the best amount use of ppp333.We have selected the suitable breeds to plant for early spring,studied the function of Se fertilizer to the potato yield and the content of Se in potato.The main results of study are as followed:1.By virus-free potato variety comparion experiments of virus-free Luyin1,Daxiyang,Jinshu8,Holand15,Shuangfen4,Dongnong303,Kexin4, we have used virus-carrying Kexin4 as ck,and taken the output as screening index,the resulting data are subjected to variance analysis and SSR multiple comparison,we have selected the suitable breeds suitd for Zaozhuang and other southern region of Shandong province,such as Luyin1,Helan15,Daxiyang,Jinshu8;Shuangfen4 can be used as substitutive breed.2.Through eight different planting density experienments of virus-free Luyin1,we had found that potato tube yield and merchandise rate by rationable planting density are both better than more density or less density. The whole trend of the density affected on output is that the output increases as the density increases.The lowest density treatment(30000standingd/hm²) has the lowest field yield,which is 41.7kg;75000standings/hm² has the highest yield,the average yield is 54.6kg.But as the density goes on to increase,the yield tends to decrease.Planting density has notable influence in merchandise rate of virus-free Luyin1.The yield is low while the planting dentisy is the lowest:as the planting density come up,the yield of tomato and merchandise rate are all gradually increasing,the difference between them increases accordingly.When the density of reament 6 is 67500standings/hm², the yield and merchandise rate reach the peak,40956 kg/hm² and 36656kg/hm² respectively.Taken the potato yield,merchandise potato yield and merchandise rate into account,52500standings/hm²ï½ž67500standings/hm² is the most suitable density at the place,and 67500standings/hm² is the best.3.In order to investigate the best amount of ppp333 in cultivating virus-freeLuyin1,the experiment of spraying different concentration of ppp333 were carried out with six treatments using ppp333 at 300g/hm²,450g/hm²,600 g/hm²,750 g/hm²,900 g/hm²,0g/hm² with a water volume of 450 kg/hm².By the yield statistic,the potato yield increaseed better when spraying ppp333 at low concentration,while high concentration was restraining the yield.The potato yield was the highest,when spraying ppp333 at 750 g/hm² concentration,and decreased when the concentration higher or lower.Spraying ppp333 have notable effects on potato's biological characteristics,mainly in plant height decreased and side branch number, stems and leaves weight,the output of stem tuber increased.The height of the treatment Spraying ppp333 is shorter than ck.Spraying ppp333 in the concentration of this experiment,the height shorter 15～30cm,15～40%than ck, side branch number increased.The treatment using ppp333 at 450g/hm² has the most side branch numbers,followed by 300g/hm².Stems and leaves weight increases apparently as the concentration of ppp333 increasing,and have no decrease trend after 900 g/hm².4.By field experiment of ratio of N/P for virus-free Luyin1,the amount of pure N(150 kg/hm²,300kg/hm²,450kg/hm²) and P₂O₅(120kg/hm²,180kg/hm²,240kg/hm²) both have three levels.Variance analysis and multiple comparisons show that:under present product situation,N300kg/hm² P₂O₅180kg/hm² is the best.5.Useing 20%Se fertilizer on virus-freeLuyin1 in early spring can increase potato tube yield,but the effect of increasing is not notable;Useing Se fertilizer on virus-freeLuyin1 in autumn,variance analysis show that the difference between different concentration and different stages is pretty evident.The difference of interaction of concentration and stages was not significant.Using 20%Se fertilizer on virus-free Luyin1 in early spring and autumn can notably increases the contents of Se in potato and qualify the food standard.Compared with ck,the yield increase rate was 25%～600%. Different using method,different concentration or different using stages,the effect is different,showed the following order:more spraying times is better than few times and high concentration is better than low concentration.The later spraying has the better effect with only one spraying time.The effect of spraying on the surface is better than root-watering.