Bull. Spec. CORESTA Congress, Harare 1994, p. 22, A 13
Tobacco and Cotton Research Institute, Rustenburg, South Africa
The demand exists to release new tobacco cultivars with a programme of cultivation practices so that the tobacco producers will have the means to exploit the potential of such a cultivar regarding the required style and quality within a limited time. The manufacturer is currently looking for a more rounded leaf with a high lamina percentage. Three new air-cured cultivars which were selected out of the phase 1 and elite breeding trials were evaluated at five localities with respect to spacing, nitrogen requirements and topping height. CDI 28 was used as the control cultivar. Two inrow spacings of 0,05 m and 0,06 m with 1,3 m between rows were used. The nitrogen levels were 300 and 400 kg ha-1 and the total leaves ha-1 for the low and high topping heights were 256410 and 307692 respectively. Differentiated drip irrigation that made provision for the water requirements of each treatment combination was used. Leaf dimensions were measured and were rewarded a point on a scale of 1 to 10 for various quality and style characteristics. Results show that a yield potential of 6000 kg ha-1 is possible and that higher plant leaf numbers ha-1 made no significant advance towards smaller rounded leaves. The 300 kg ha-1 nitrogen level produced the most positive results. Body and oiliness were sacrificed in the effort to achieve higher yields. In conclusion the results underlined the fact that the wrong genetic selection cannot be rectified by cultivation practices.