Abstract: Using 11 gourd germplasms,the simulated heat stress experimentation was carried out in an artificial climate chamber.Heat damage to the gourd germplasms as indicated by the heat stress index,relative conductivity,MDA,POD,SOD,Pro and other physiological and biochemical changes was evaluated.Through 6 physiological and biochemical correlation,principal component and cluster analyses,the heat resistance of these germplasms was determined.The results showed that(a)in 7 days under artificial treatment,the heat-resistance of the germplasms could be effectively differentiated;(b)it was possible to apply analyses using the 6 physiological and biochemical parameters yielded 4 variables for the Euclidean distance cluster analysis for further evaluation of the differences on gourd's heat resistance;and(c)the cluster analysis identified 4 heat-sensitive,6 moderate heat-tolerant and one heat-tolerant germplasm.

Key words: Lagenaria siceraria(Mol.)Stand, heat tolerance, physiological and biochemical properties