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The early growth of six cacao varieties important in the breeding program of the Cocoa Research Institute was investigated in sand cultures supplied with optimum and deficient levels of plant nutrients. The varieties tested were the Amazon selections Nanay (Ny) and Parinari (Pa), West African Amelonado (A), and their hybrids, NyA, PaA, and NyPa. Varieties Ny, NyA, and NyPa had similar growth patterns and were the fastest growing; varieties PaA and Pa were similar and the next best; and A was the slowest growing. In the control solutions variety Pa was larger than variety A, but in all deficient nutrient treatments except the calcium-deficient one, the two varieties grew to equal size.Nutrient levels in the leaves did not vary greatly between varieties, and apparently were not correlated with plant growth. The larger, more vigorous varieties had a higher percentage of small lateral absorbing roots than did the less vigorous varieties.The Amazon varieties Ny and Pa grew significantly less in the potassium-deficient nutrient solution than did the Amelonado variety A when compared with their controls. In addition, the symptoms of potassium deficiency exhibited by the Amazon varieties were more severe than those of the Amelonado variety.

SUMMARY Shading retarded the growth of cocoa seedlings infected with cocoa swollen‐shoot virus proportionately more than the growth of uninfected seedlings. Infected seedlings grown in bright light did not produce the swellings on stems and roots which were consistent symptoms of infection on plants grown under shade. The type of leaf symptoms also differed in shaded and unshaded seedlings. Attention is drawn to the possible implications of shade in the severity of swollen‐shoot outbreaks in farmers' cocoa.

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