July 15, 1920 



Presoak Method of Seed Treatment 



369 



Table III. — Effect of g hours' presoaking followed by formalin i : 400 treatment 



Treatment. 



Percentage of germination. 



China. 



Blue- 

 stem. 



Exp. 

 V. 



Exp. 

 VI. 



Aver- 

 age. 



Mar- 

 quis, 

 Exp. 

 VI. 



Control 



Formalin 1:400 for 10 minutes, covered 12 



hours 



Formalin 1:400 for 10 minutes, covered 3 



hours 



Water for 10 minutes, covered 9 hours, 



formalin 1:400 for 10 minutes, covered 3 



hours 



70 

 60 



78 

 60 



67 



72 



46 

 40 

 35 



45 



50 

 43 

 23 



42 



42 

 29 



44 



59 

 56 



49 



58 



Table III shows for the presoaked seeds not only a decrease in injury 

 over the 3-hour treated seeds as previously observed but also a decided 

 increase in germination over the seeds treated 12 hours with formalin. 

 The latter show a loss of 10 to 18 per cent, the former a loss of only 3 

 to 6 per cent. At the same time the presoaked seeds produced larger 

 and more vigorous plants than the controls. 



Very clearly the presoak treatment followed by 3 hours of formalin 

 treatment showed a distinct advantage over the usual formalin treatment. 

 As this appeared to be a promising method of reducing formalin injury, 

 a thorough test was then made with all the varieties of wheat at hand. 

 It appeared possible that for some varieties a 9-hour presoak might 

 begin germination before treatment, thus rendering the seeds very 

 susceptible to injury, whereas, a formalin-treatment period longer 

 than 3 hours appeared desirable for control purposes. For these rea- 

 sons, the presoak period was reduced to 6 hours, followed by a 6-hour 

 treatment with formalin. 



EFFECT OF 6 hours' PRESOAKING FOLLOWED BY FORMALIN I TO 40O TREATMENT ON 

 GERMINATION OF WHEAT SEED 



The presoak treatment in every instance was given by soaking the 

 seeds lo minutes in water, then draining off the surplus water and keep- 

 ing the seeds in moist chambers 6 hours, allowing the seeds to absorb the 

 surface moisture film during this period. After shaking off all possible 

 surface water, the next step was to soak the seeds thoroughly in a i to 

 400 formalin solution, stirring and rinsing up and down to bring the 

 solution in contact with each kernel. After 10 minutes in this solution 

 the seeds were removed, drained, and kept moist for 6 hours in moist 

 chambers previously rinsed with the same solution. After treatment 

 the seeds were dried overnight and planted in the greenhouse, 100 seeds 

 per pot, in duplicate or triplicate. 



