Family Convolvulaceae 177 



from the mother cuttings. However the growing of 

 slip seed every year is a tedious process. To im- 

 prove the strain and avoid disease slip seed may be 

 grown every second or third year, from hill selected 

 primes. Following the use of such slip seed, primes 

 may be used for one or two seasons, to be followed 

 again by a high strain of slip seed. Roots which are 

 round, chunky, and smooth should be chosen. Seeds 

 which have sprouted in storage should be discarded, 

 as these roots often carry diseases. The seed of some 

 varieties, however, are known always to sprout, no 

 matter under what storage conditions they are kept. 

 In these cases, the sprouts should be broken or rubbed 

 off and the seed be treated with corrosive sublimate 

 before being bedded. No injury results from this 

 process and new sprouts soon follow. As the seeds 

 are being carefully selected one by one, the stem end 

 of each root should be clipped off with a sharp knife to 

 a distance of one third of an inch. Every cut surface 

 should present a clean white appearance. Brown 

 spots in the interior of the root mean the presence of 

 disease in the vessels. Such seeds should be discarded, 

 even though the exterior is healthy looking. In us- 

 ing primes for seeds, selection should be made in the 

 fall at digging time. The roots from the highest yield- 

 ing and healthiest hills should be chosen, marked, and 

 stored separately under the best possible conditions. 

 Before bedding, these should be sorted over again and 

 the stem ends of the most choice should be clipped to 

 make sure of their freedom from internal disease. 



Seed Treatment. Having selected good sound seeds, 

 12 



