Sundus Abdulkariem Alabdulla There is no linear correlation between these two features. Look at Porter, J. R. (1984). A model of canopy development in winter wheat. The Journal of Agricultural Science, 102(2), 383–. doi:10.1017/s0021859600042714 

To some extent, yield potential of a rice cultivar may be characterized by tillering capacity. But, rice plants with more tillers can show a greater inconsistency in mobilizing assimilates and nutrients among tillers, resulting in variations in grain development and yield among tillers.

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/tillers

Please also check:

https://www.researchgate.net/publication/333081406_TILLER_PRODUCTIVITY_AND_SURVIVAL_AS_DETERMINANTS_OF_GRAIN_YIELD_FOR_SELECTED_RICE_GERMPLASM

Yes! Branching patterns or formations are critical in yield of cereal crops. This is due to the fact that branches carries plant leaves which help to accumulate photosynthate in other words, the leaves (careied by branches) are photosynthetic medium through which plant accumulate and transfer stored starch for growth and development (this implies high yield) Branching crops have canopies which enable them shade weeds, they grow faster and develop rapid.

Check https://www.researchgate.net/publication/257890142_Modeling_branching_in_cereals

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3794302/

Also check https://www.mdpi.com/2077-0472/11/1/69/htm

https://www.nature.com/articles/s41598-020-77467-3

Yes, in particular rice which has tillers. Check on this paper

Article Modeling branching in cereals