Inheritance of Resistance to Blotchy Ripening in Processing Tomatoes

Abstract

Inheritance of resistance to blotchy ripening In tomato (Lycopersicon esculentum Mill.) cultivars intended for machine harvest was studied in two diallel crosses using the Hayman and Griffing analyses. Additive effects were most important as indicated by the high level of general combining ability compared with specific combining ability. Some hybrids performed better than the mid-parent mean; however, heterosis for resistance to blotch above the best inbred line was not evident. Epistasis occurred between recessive genes in two parents, resulting in reduced blotch. No significant interaction between the expression of blotch in diallel progeny and K availability was evident. Genotype-environment Interaction was significant, but relative variation in blotch between experiments only occurred in cultivars with an intermediate level of resistance.