Row of tomato plants (IMAGE) Penn State Caption The grafted tomato plants involved in the research produced seed that resulted in progeny that were, on average, 35% more productive. And that growth vigor persisted in the progeny over five generations in the study. Credit Penn State Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.