Modelling leaf growth in Garlic

When scientists build a crop growth model, there are two major features they try to capture, Phenology and Morphology. Morphology is the study of shape. This is necessary to see what the plant will become. Phenology studies the timing of growth, so this reveals how a plant becomes what it is. Modelling is used for a lot of crops, but one plant hasn’t had a lot of attention. A new paper by Jennifer Hsiao and colleagues takes a look at modelling garlic, Allium sativum.

If you’re trying to think of models for garlic, and failing to remember any, there is a reason why it’s difficult. Jennifer Hsiao said: “Numerous crop simulation models are available for staple and other field crops of economic importance, few models exist for speciality crops like garlic with cultural and horticultural significance. Our motivation was to fill this knowledge gap by developing a complete crop model that can be used for optimizing crop management, improving crop phenotypic traits, and understanding crop physiology, ecology, and crop systems dynamics.”

Crop modelling sounds like something that would be centred around the growing plant. However, Hsiao and colleagues also look at what comes before. Garlic is grown from bulbs. The team found that how you store those bulbs can affect how the plants grow. Hsiao said: “Storage conditions can greatly influence several post-storage growth and development aspects in the field in garlic. We see that when bulbs are stored longer, more leaves initiate during the storage period, and the rate of leaf appearance increases once the bulbs are planted. This accelerated development may lead to a difference in yield, and the final outcome also depends on when the bulbs were planted, and the weather conditions then. We see our model being able to provide information to crop advisors and growers on how storage duration and planting time can affect the overall outcome of growth and yield.”

Bulb storage isn’t so much of an issue for models of plants without bulbs. But can the lessons learned in this paper be applied to other bulb plants, like onions or tulips? Hsiao said: “Our model is specialized for simulating the growth and development of hard-neck garlic crop, but certain aspects of the model are transferable to other crops and plants within or outside of the Allium genus. Our modeling approach may be applicable to other bulbous crops such as onions and tulips that share similarities with garlic with similar plant structure, post-harvest physiology and storage requirements, and phenological characteristics such as overwintering. While we see our model structure to be generalizable to several other bulbous plants, specific measurements and calibrations tailored for each crop will need to be made.”

The model builds on earlier work on the physiology component of crop growth, by Professor Soo-Hyung Kim and colleagues. This research concentrated on photosynthetic and transpiration responses to photosynthetic photon flux (PPF), carbon dioxide concentrations, and temperature.

The new article has the potential to spur plenty of future research. Professor Kim said: “Directions of future work relating to our study include extension and refinement of the model focusing on incorporating responses to environmental stressors such as water and nutrients, developing crop management strategies for enhancing resource use efficiency, and investigating the impacts of projected changes in our climate system such as temperature and CO2 concentrations. We also see opportunities in applying the model for addressing questions ranging from novel breeding strategies to identify site- and climate-specific crop phenotypes, yield projections under a changing climate, and resource use efficient management practices for climate mitigations.”

A process-based model for leaf development and growth in hardneck garlic (Allium sativum) is obviously relevant to crop modellers and breeders. However, as Hsiao and colleagues point out, Alliums are also popular horticultural plants. Computer-modelled alliums may yet end up in gardens of keen amateurs as well as in commercial farms.