Several lines of triticale (X Triticosecale Wittmack), varying in their degree of shrivelling, were grown in the field. The ratio of the final seed volume to the maximum volume attained during development was used as a measure of shrivelling. Shrivelling was correlated with total dry matter in the seed, but not with its maximum size. When rates of dry matter accumulation were normalized with respect to maximum seed volume, two families of curves were found. The shrivelled lines exhibited a lower rate and shorter duration of dry matter accumulation than the plump ones.