VARIETAL DIFFERENCES OF ROOT SYSTEMS IN WINTER-WHEAT SEEDLINGS

Varietal differences in root system morphology in winter wheat (Tritic um aestivum L.) were investigated using seed pack growth pouches in a greenhouse. Different genotypic cultivars, shorter B-288 D for dwarf t ype, Pioneer 2548, Clark and Madison for semi-dwarf type, Cardinal and Verne for tall type, were used in this experiment under two different nutrition levels (NO3-N; 10 mg/l and 50 mg/l) with three replications . One germinated seed of each cultivar with primary seminal root less than 1.0 mm in length was transplanted into each seed pack on Dec. 5, 1991. Significant varietal differences were recognized in the spread o f the root system, but there was no diffrence between the nutrition le vels. Madison and Shorter B-288 D showed a large spread of the root sy stem, whereas Cardinal showed a small spread. Total root length per pl ant was significantly different among the cultivars, with Cardianl sho wing the largest total root length per plant and Shorter B-288 D showi ng the smallest. On the other hand, there were no significant differen ces in stem number or leaf number per plant. These varietal difference s in the lateral spread of the root system and total root length per p lant were considered to be controlled by genotypic parameters. The sem i-dwarf gene in wheat that affects the plant type did not influence th e spread of root system and total root length per plant.