Green beans are one of the crops we refer to as a ‘multi-fruiting’ crop, which is a crop that blooms and sets fruit for an extended period, and has the capacity to increase the number of buds based on health and nutritional integrity.
Beans can have one pod per node or a dozen. Tomatoes can have two tomatoes per cluster, or ten. Cucumbers can have one female bud per node, or three. For these multi-fruiting crops, it is possible to produce large yield increases by increasing the number of fruit per plant when we make sure the soil has the capacity to deliver all the nutrition needed to fill the fruit load.
The key to producing short tight internodes and many fruit buds is to make sure these plants have an abundance of cytokinins being produced each day. (There is a closely connected conversation about maintaining a balance between nutrients which drive vegetative growth and reproductive growth, which you can learn about in the podcast here.)
Cytokinins are produced in growing root tips and cobalt is a key enzyme cofactor needed for cytokinin synthesis.
The key is that a growing root tip is needed to produce cytokinins, particularly at the stages of bud initation and pollination.
A healthy disease resistant plant will always be cytokinin dominant, rather than auxin dominant. This means they will always have more growing root tips (producing cytokinins) than they have growing shoot tips or seeds (producing auxins). It also means that these plants will have larger root biomass than vegetative biomass.
This is a topic worth diving deeply into, particularly if you are growing these types of crops.
Increasing the pod count on soybeans by more than 50% is easy. Filling those beans to produced an increased yield is where the focused attention needs to be. Similar increases are possible on many other crops.