a1 Tea Research Foundation of Central Africa, PO Box 51, Mulanje, Malawi
Temperature is the major environmental variable affecting the yield of tea, but within the framework of a temperature model shoot extension is severely depressed when daily maximum vapour pressure deficits rise above 2.3 kPa. Day length does not affect shoot extension when the nights are cool (10°C), but growth rate is depressed by short days (11 h) when nights are warm (20°C). Soil temperatures between 18–25°C do not affect shoot extension.
(Accepted August 08 1981)
p1 Present address: Department of Civil Engineering, The University, Southampton, UK.