Influence of Environment and Flower Maturity on Hybrid Seed Production of Exserted Stigma Tomatoes Crossed without Emasculation1

Abstract Two inbreds of tomato ( Lycopersicon esculentum Mill.) with exserted stigmas, one without and the other with positional sterility (ps) , were crossed without emasculation, at 3 stages of maturity under 3 environmental conditions. Seed production was maximal when flowers at anthesis were pollinated during cloudy weather with relative humidities (RH) of about 70% and temperatures about 24°C. Seed production was poor when flowers were pollinated 3 days before anthesis during hot (32°C), clear, dry weather (RH - 48%). The ps inbred had less than 1% selfing at all stages of flower development and environments. Selfing contamination for the ps + inbred was less than 4% per line except in some cases when flowers were crossed before anthesis. Selfing of 35% occurred when flowers were crossed 3 days before anthesis during favorable pollinating weather.