Anatomical and Histological Studies of Grafted Tomato with Interspecific Solanaceous Rootstocks

A study was carried out at the Department of Vegetable Science, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu,India during 2019-2020 to assess the anatomical and histological changes within the graft union of tomato and identify compatible rootstocks for improved propagation of the crop. This experiment involved rootstocks of three wild tomatoes including Solanum torvum, S. sisymbrifolium and S. capsicoides and scions of two tomato hybrids including TNAU tomato hybrid CO3 and Shivam. The grafting was done using the cleft grafting method. The anatomical and histological sections of six graft combinations and two tomato scion samples were viewed microscopically at 7, 14 and 21 days after grafting (DAG). Among the six tomato graft combinations, S. torvum rootstock showed complete development of vascular connection at 21 DAG followed by S. sisymbrifolium rootstock, whereas S. capsicoides rootstock showed only callus growth at 14 DAG. Scion growth dominated the rootstock growth in S. torvum rootstock leading to mismatch of scion-rootstock stem thickness and delayed epinasty symptom at the later stages of plant growth. Of the rootstocks of the three species studied, S. sisymbrifolium rootstock was compatible for tomato grafting though it exhibited delayed vascular connection between the scion and rootstock.