Table 2. — Yield of A5 clones as related to sex and chi-square 



analysis'^ 



Yield (g) 



Male 



Female 



Total 



0-1,000 





2 



2 



4 



1,000-1,500 





5 



11 



16 



1,500-2,000 





8 



3 



11 



2,000-2,500 





2 



5 



7 



2,500 or more 





1 



6 



7 



Total 



18 



27 



45 



iZ^ = 7.89; P = 



about 0.5. 









Table 3. — Yield of 4-5 clones as related to geographical origin and 





chi-square analysis^ 







Yield (g) 



West Indies 



Guyana 



Hybridization 



Total 



0-1,000 



3 



1 



0 



4 



1,000-1,500 



11 



5 



0 



16 



1,500-2,000 



3 



4 



4 



11 



2,000-2,500 



2 



2 



3 



7 



2,500 or more 



1 



4 



2 



7 



Total 



20 



16 



9 



45 



= 13.20; P = about 0.5. 



supply of water. More care is necessary to achieve maximum yields 

 in D. trifida, but this effort pays in economic return. 



In tables 2 and 3, chi-square tests are presented to test the 

 relationship of yields of 45 clones to sex of clone and geographical 

 origin. These data suggest that there is no reason to believe that 

 either sex or geographical origin influences yields. 



STORAGE 



Yam varieties that need long growing seasons have been 

 shown to have correspondingly short storage seasons- D. trifida is 

 no exception. Varieties differ in storability from a week to 2 

 months. Normal ambient-temperature storage is then terminated 

 by sprouting. Although sprouting can be suppressed by eliminating 

 sprouts, the quality and food value of sprouted tubers decline rapid- 

 ly. Some year to year (environmental) conditions also affect stor- 

 age time. The storage time for 'Cousse-Couche Violette' is about a 

 month; that of 'Cousse-Couche Belfort' is 50 days. Up to 20 percent 

 of the dry weight of the tuber can be lost during storage. 



Injury at harvest, especially the breaking of the stolon, results 

 in a fungus infection. Penicillum oxalicum is an especially trouble- 



20 



