Morphology and fractal dimension of root systems of maize hybrids bearing the leafy trait

A rapid and accurate assessment of root morphological characteristics can be important for identifying promising plant genotypes. Scanner-based image analysis has made the measurement of root morphology faster, more accurate, and less subjective, and allows for estimation of fractal dimension (FD). We used scanner-based image analysis to investigate root morphology in leafy vs. conventional maize (Zea mays) genotypes. Two experiments were conducted following a completely randomized design with ten and five replicates. In the first experiment, treatments were factorial combinations of four hybrids (leafy reduced-stature (LRS), non leafy-reduced stature (NLRS), leafy normal stature (LNS), and non leafy normal stature (conventional commercial) hybrid, Pioneer 3979 (P3979)), and four sampling dates (5, 10, 15, and 20 days from transfer to growth pouches). In the second experiment, plants were grown for 15 days from emergence in 10-L plastic pots. This experiment included three maize genotypes (LRS, LNS, and Pioneer 3905 (P3905)). The FD of young root systems was similar for leafy genotypes (FDapproximate to1.66) and was higher for P3905 (FDapproximate to1.74). The FD correlated with root characteristics generally included in root growth models (0.68less than or equal torless than or equal to0.87). Thus, FD could be used to summarize a number of root morphology variables.