High-throughput phenotyping reveals differential transpiration behavior
within the banana wild relatives highlighting diversity in drought
tolerance
Abstract
Crop wild relatives, the closely related species of crops, may harbor
potentially important sources of new allelic diversity for (a)biotic
tolerance or resistance. However, to date wild diversity is only poorly
characterized and evaluated. Banana has a large wild diversity but only
a narrow proportion is currently used in breeding programs. The main
objective of this work was to evaluate genotype-dependent transpiration
responses in relation to the environment. By applying continuous
high-throughput phenotyping, we were able to construct genotype-specific
transpiration response models in relation to light, VPD and soil water
potential. We characterized and evaluated 6 (sub)species and discerned
four phenotypic clusters. Significant differences were observed in leaf
area, cumulative transpiration and transpiration efficiency. We
confirmed a general stomatal-driven ‘isohydric’ drought avoidance
behavior, but discovered genotypic differences in the onset and
intensity of stomatal closure. We pinpointed crucial genotype specific
environmental conditions when drought avoidance mechanisms were
initiated and when stress kicked in. Differences between (sub)species
were more pronounced under certain environmental conditions,
illustrating the need for high-throughput dynamic phenotyping, modelling
and validation. We conclude that the banana wild relatives contain
useful drought tolerance traits, emphasizing the importance of their
conservation and potential for use in breeding programs.