Abstract: | Ramets of Lolium perenne from the same genotypes were grownin nutrient solutions of two concentrations. Additional mineralnutrition increased the rate of production of new tillers, therate of increase in size of tillers and the rate of productionof new roots, but not the rate of growth of individual mainroots. The genotypes differed considerably from each other intheir rates of growth, especially of shoot growth. When thegrowth-rate of the same population of genotypes was alteredby changing the environmental conditions it was found that thelower the mean rate of shoot growth, the greater its coefficientof variation. Variation in the rate of shoot growth, due tomineral nutrition and genetic constitution of the plants growingin a dilute nutrient solution, was accompanied by a similarbut smaller variation in the number of roots. |