Breeding for drought tolerance is among the more challenging tasks in rice breeding. Although ample genetic variability has been reported for components associated with drought tolerance and grain yield, combining them favorably has been rather difficult. Thus, the foremost challenge to breeders of this fragile ecosystem is to identify the trait(s) that would confer a grain yield advantage in crops challenged by low moisture stress, and devise suitable selection strategies, as phenotyping some drought tolerance components involves destructive sampling.
Root system characters are important for drought tolerance in rice. Combining higher grain yield with a deep root system is desirable. In breeding experiments, where each genotype has a unique genetic constitution, we need to assess root morphology at the vegetative stage (after imposing low-moisture stress or in well-watered conditions) and forward the filial generation. To achieve this, we adopted a singletiller approach. Annual rice has evolved from perennial wild. A single or a few tillers removed from the mother plant and planted could grow and yield grains. We assessed the performance of replanted tillers and compared these with corresponding characters of undisturbed plants.