Chickpea (Cicer arietinum L.) is being rapidly adapted to the semiarid northern Great Plains, but little is known about the morphological responses of this annual grain legume to the dry environment. This study, conducted in southwestern Saskatchewan, examined the morphological plasticity of three market classes of chickpea by growing the crop at four plant population densities. Chickpea grown at high (50 plants m−2) population density produced approximately half as many fertile pods per plant as those grown at low (20 plants m−2) density, but total number of pods per unit area increased with increasing plant population density. Large‐seeded kabuli chickpea produced fewer pods per unit area, or <60% of that produced by small‐seeded kabuli, and <50% of that by desi chickpea. Infertile pods accounted for 17 to 23% of the total pods for large‐seeded kabuli, compared with 9 to 12% for small‐seeded kabuli, and 6% for desi chickpea. The large‐seeded kabuli produced <87 seeds for every 100 pods produced, whereas desi and small‐seeded kabuli produced >110 seeds for every 100 pods. Consequently, the large‐seeded kabuli chickpea produced <90% of seed yield per unit area than small‐seeded kabuli and desi chickpea. As plant population increased from 20 to 50 plants m−2, the seed yield m−2 increased by 20% for desi and 27% for small‐seeded kabuli, but only 17% for the large‐seeded kabuli chickpea. In the semiarid northern Great Plains, seed yield potential of desi and small‐seeded kabuli chickpea can be increased by increasing plant population density, whereas the seed yield of large‐seeded kabuli can be improved by increasing percentage pod fertility.