Variation in net photosynthetic rates of sugar cane leaves and differences in the ratio of red:far-red light beneath the canopy among varieties with different ratooning capacities.

The work reported in this paper is part of a project aimed at understanding what constitutes a good ratooning sugar cane variety. The objective is to define characteristics that could be used as selection criteria in cane breeding programs to improve the yield of ratoon crops. Here the authors specifically report investigations into whether cultivars that differ in their ratooning ability have different leaf net photosynthetic rates and different red:far-red ratios at the base of crop canopies. Leaf net photosynthetic rate was chosen because it is one of the factors that contributes to cane yield. The red:far-red ratio was chosen because it influences the tillering of grasses (Casal et al., 1987). If this is the case for sugar cane, red:far-red ratio at the base of canopies may affect ratoon yields via the number of stalks per hectare, which is an important determinant of sugar yield.