Sources of Resistance in Tomato Against Fruitworms

Abstract

Screening of tomato gennplasm for resistance against fruitworms (Phthorimaea operculetta and Helicoverpa armigera) was carried out under natural infestation in the field for three crop seasons starting in 1992 at the Melkassa site of Nazareth Research Centre, Ethiopia. Out of 87 genotypes evaluated in succession, four were identified to be resistant. These were: ‘Pus a Early Dwarf’, 'Pusa Ruby’, ‘Seedathing’, and ‘Serio’. ‘RV-44’ and the commercial variety ‘Money Maker* were moderately resistant whereas ‘Marglobe’ was susceptible. ‘Serio’ was also the highest yielder, with marketable yield advantage of nearly 36 and 132 percent over thecommercial varieties ‘Money Maker’ and ‘Marglobe’, respectively. There were strong positive correlations between damage caused by fruitworms and fruit size. Significant correlations between fruit damage and number of larvae per 100 fruit were also observed during the three seasons; however, it is suggested that percent fruit damage is a more reliable and practical measure of resistance than number of larvae.