Figure 11. — Yams stored in a yam barn. 



PN-5225 



of sound yams. Damaged tubers should be used as soon as feasible 

 or converted to flour. But even apparently sound yams are 

 susceptible to rotting if they have been damaged by insects and 

 nematodes. 



Although fungicides protect yams from deterioration, they 

 are a health risk for humans and should be restricted to treatment 

 of seed tubers. On the other hand, washing with lime or dusting 

 with wood ashes are simple treatments that effectively reduce rot. 



Tubers of D. rotundata have been stored in Puerto Rico for 

 a full year (25) at 16° C and 80 percent relative humidity. 

 Tubers begin to sprout, but sprouting never advances beyond the 

 production of a ''button." Storage below 10° to 12° C may lead to 

 the development of what Coursey calls ''chilling damage" (P). 

 After a few weeks at low temperatures permanent physiological 

 damage is done. When returned to normal temperatures, rapid 

 internal breakdown occurs: tubers become watery and develop 

 objectionable odors. 



In Puerto Rico breakdown at normal or ambient temperature 

 has been seen. After 3 or 4 months the bark of the tuber becomes 

 watery and tends to loosen from the underlying parenchyma. The 

 quality of the flesh is also lowered. Except when refrigeration 

 with humidity control is available, the maximum storage life of 

 D. rotundata tubers is 4 months and of D. cayenensis, 2 months. 



CULINARY CHARACTERISTICS 



Although the tubers of D. rotundata and D, cayenensis are 

 somewhat large for home use, they are generally fairly smooth and 

 lack awkward appendages. When produced in rocky or hard soils. 



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