Field investigations conducted at Ludhiana (India) showed that the foliar application of 2-chloroethyltrimethyl-ammonium chloride (CCC) (50% a.i.) at 300,600 and 900 ml/ha about 5 weeks after planting did not depress plant height. The dose of 600 ml CCC/ha was most effective and increased seed yield by 1·31 and 0·74 t/ha over the control (water spray) in 1978–9 and 1979–80, respectively. The corresponding increases in total yield were 1·37 and 0·86 t/ha. However, in 1980–1 when CCC was applied 3 weeks after planting even the lower dose of 300 ml/ha depressed the plant height. Then the treatment of CCC increased significantly the number of tubers of seed size and seed yield by decreasing the ‘ware’ yield but did not influence the total yield. The yields of potatoes were not affected signifioantly by the application of N-dimethyl amino succinamic acid (B 9) and succinic acid (SA).
In an experiment where the interaction of nitrogen and CCC was studied both factors not only increased the seed yield but also increased the total yield. However, there was no interaction between nitrogen and CCC.