SUMMARY The effects of temperature were studied on six root and shoot characters in pea (Pisum sativum) seedlings. The growth response of characters to13, 16 and 19 oC in seven genotypes was linear after 9 days from sowing with growth increasing with increase in temperatures. The response to accumulated heat units of 135 oC at these three temperatures was different with a peak in growth at 16 oC. A regression analysis of genotype‐environment interactions indicated that JI181, one of the primitive forms, showed the least response to environmental change. A major portion of the genotype‐environment interaction was due to the heterogeneity of the regressions but the non‐linear or residual portion was also significant in many characters. The least variable character over all genotypes was the length of the root which was bearing laterals.