A single recessive gene designated Jn by Bernard and Weiss (1972) controls the inheritance of the lanceolate trifoliolate in soybean. They state that the narrow-leaf condition is associated with a high number of four-seeded pods, which they attributed to a pleiotropic effect of the Jn gene. No yield differences have been found between narrow and normal leaf types using isolines.
Dinkins, R. D.; Edwards, L. H.; McNew, R. W.; and Kunta, T.
"Research Notes : United States : The effect of the narrow-leaf gene in a segregating population,"
Soybean Genetics Newsletter: Vol. 12
, Article 27.
Available at: http://lib.dr.iastate.edu/soybeangenetics/vol12/iss1/27