GENETIC-VARIABILITY OF ROOT-GROWTH IN WHEAT (TRITICUM-AESTIVUM L)

Ten wheat genotypes were examined for their pattern of root development in glass-fronted growth containers in the greenhouse. Differences between genotypes were recorded in the number of first-order lateral roots at 2, 3 and 4 weeks’ growth, the number of second-order lateral roots, the maximum depth of penetration, and the angle between the seminal root axes at 4 weeks’ growth and the length of lateral root per 10 cm depth increment at 5 weeks’ growth. Significant positive correlations existed between many of the seminal root parameters. Differences between genotypes in the length of nodal root axes were recorded at 7 and 8 weeks’ growth. Nodal root length was influenced by tiller number and the rate of tiller initiation. Tiller development, and consequently root growth, was related to plant phasic development. Genetic modification of seminal root development appears possible, with the direction of selection depending on the definition of an optimum root development pattern. © 1979 CSIRO.