The pollen viability and the daily changes of 2 wild tobacco resources(Nicotiana alata,N.gossei) and 1 cultivar(K326) were measured by TTC method.The receptivity of stigma was measured by benzidine-hydrogen peroxide method,and the stigma receptivity changes of different flowering days were measured by pollination test.The reproductive characteristics of 3 tobacco resources were analyzed by estimating pollen ovule ratio(P/O),hybrid breeding index (OCI) and pollination test.The results showed that:(1)The pollen viability of N.gossei(74.9%) was significantly higher than that of K326(52.2%) and N.alata(45.3%),but there was no significant difference between K326 and N.alata.The daily changes of pollen viability of 3 tobacco resources showed bimodal curves,the peaks at 13:00 and 15:00,respectively.Both the lowest daily pollen viability of 3 tobacco resources and the highest daily temperature appeared at 14:00.(2)The stigma receptivity of K326 was significantly higher than that of N.alata’s and N.gossei’s,but there was no significant difference between the 2 wild resources.The optimal pollination periods of different resources were different.Stigma receptivity of N.gossei might maintain highly from before 1 day to after 4 days of flowering day.The optimal pollination period of N.alata was 2-3 days after flowering day,while the optimal pollination period of K326 was from before 1 day to after 1day of flowering day.(3)The reproductive type of K326 was self-compatible,with some outcrossing phenomena.N.alata and N.gossei were mainly outcrossing.But N.gossei was self-compatible,and the self-compatibility of N.alata was poor.The results indicated that the stigma receptivity of wild resources significantly influenced their fecundity.Low seed-set rate of N.alata was mainly due to self-incompatibility,otherwise the lack of effective pollination was the main reason causing low seed-set rate of N.gossei.