Inbreeding depression study was carried out in 10 x 10 diallel cross excluding reciprocals of sponge gourd during 2004–2006 and data were analyzed for inbreeding depression. The analysis of variance revealed significant differences due to treatments, crosses and interaction (parents vs crosses) for all the characters under study during kharif and summer. The inbreeding depression results due to fixation of unfavorable recessive genes in F2. In the present results high inbreeding depression indicates the presence of non-additive gene action (dominance and epistasis) forthe traits like first female bud initiation, fruit weight, vine length and number of fruits per plant. Significant inbreeding depression was noticed maximum for fruit yield (34.72%) during both the year. The minimum inbreeding depression was observed in cross VR-104 X VR-103 (13.51%) followed by NSG-28 X PusaSupriya (13.33%) for fruit yield.
