Primary factors affecting plant growth (as mentioned) in high-gravity environments include structural rigidity, capillary action, cellular mechanisms such as photosynthesis, pollination, and seed growth. This is mostly speculation, however, as I have not done the mathematical calculations behind these - I would say, however, that this would be a fairly good starting point. As other answers have mentioned, there is little rigorous analysis, and at some point there will be genetic or breeding/cultivar variations that would be more suited to this new environment.
Structural Rigidity
Terrestrial plants will need to adapt to the increased gravity by developing stronger stems and roots. Crops with low height and wide-spreading roots, like potatoes and other tuberous plants, will fare better in these conditions. Additionally, plants with flexible stems, such as willow or bamboo, can withstand the increased gravitational force due to their natural resilience. Bamboo especially has unbelievable resilience, and the fast-growing ones would likely survive in such an environment.
Capillary Action
In high-gravity environments, the efficiency of capillary action will decrease due to the greater force acting against the upward movement of water and nutrients. However, plants with shallow root systems and lower overall height, like lettuce and spinach, will be able to maintain adequate hydration and nutrient absorption under these conditions.
Cellular Mechanisms
Photosynthesis efficiency will not be directly affected by gravity; however, the increased pressure on plant cells might lead to subtle changes in cellular processes. Plants capable of adapting their cellular mechanisms to cope with higher gravitational stress will succeed in high-g environments.
Pollination
High gravity may impede the movement of pollinators like insects and birds, reducing the chances of successful pollination. To overcome this challenge, self-pollinating crops like beans or tomatoes that rely less on external pollinators are more likely to thrive.
Seed Growth
High-gravity environments will require seeds to have a higher energy reserve for germination due to the increased force they must overcome during establishment. Seeds from hardy plants such as grains (wheat, barley) or legumes (peas, lentils) will be better suited to germinate under these conditions.
Aquatic Plants
Aquatic plants, with the support provided by buoyancy, will indeed fare better in high-g environments compared to terrestrial ones. The buoyancy of water scales with gravity, allowing aquatic plants to maintain their structural integrity and capillary action more effectively. Crops like rice and watercress, which are adapted to grow in aquatic environments, will be suitable choices for cultivation in high gravity conditions.
Summary
In summary, on a high-gravity planet, the most successful crops will likely be those with low height and shallow root systems (e.g., potatoes, lettuce, spinach), flexible stems (e.g., willow, bamboo), self-pollinating mechanisms (e.g., beans, tomatoes), or the ability to grow in aquatic environments (e.g., rice, watercress). Additionally, hardy seeds from grains and legumes will have a higher chance of germination due to their energy reserves. It is essential to note that these plants may still require some adaptation or genetic modification to optimize their growth under such extreme conditions.
I did trip on this article when reading, which might be useful: https://www.sciencedirect.com/science/article/abs/pii/S1084952117305864