Journal of Agricultural Science; Vol. 5, No. 10; 2013 ISSN 1916-9752 E-ISSN 1916-9760 Published by Canadian Center of Science and Education 155 Molecular and Horticultural Characteristics of In vitro Induced Tomato Mutants Tarek A. Shalaby 1 & Antar El-Banna 2 1 Horticulture Department, Faculty of Agriculture, Kafrelsheikh University, Egypt 2 Genetics Department, Faculty of Agriculture, Kafrelsheikh University, Egypt Correspondence: Antar Salem, Genetics Department, Faculty of Agriculture, Kafrelsheikh University, 33516 Kafr El-Sheikh, Egypt. Tel: 20-106-115-7294. E-mail: antarsalem@yahoo.com Received: July 24, 2013 Accepted: August 15, 2013 Online Published: September 15, 2013 doi:10.5539/jas.v5n10p155 URL: http://dx.doi.org/10.5539/jas.v5n10p155 Abstract In addition to the traditional breeding approaches, genetic variability in tomato can be induced also by means of mutagenesis. The objective of this study was to develop an In vitro technique suitable for mutation induction on tomato and characterize them by RAPD and SSR markers as well as horticultural characteristics. The influence of various concentrations (0, 0.07, 0.14 and 0.25%) of the chemical mutagen, Ethyl Methane Sulfonate (EMS), on the in vitro shoot formation from cotyledon explants of two tomato cultivars was studied. The percentage of responding explants ranged from 45.2 to 95% in dependence on genotype and EMS concentrations. Two PCR-based techniques, RAPD and SSR, were used for analysis of genetic variations in regenerated plants from in vitro cultures combined with EMS treatment (0.25%). The percentage of polymorphism detected by RAPD and SSR primers reached 25.64%. Grouping of the original cultivar and their mutants indicated the genetic distinctness as they are placed in different clusters/groups far from each other. Mutants regenerated from the wide cultivated cultivar in Egypt (Super strain B) were evaluated with their origin cultivar in a field experiment for yield potential and fruit quality. The results revealed that the mutants were differed in number of branches, early and total yield, average fruit weight, fruit firmness and TSS content. Moreover, mutant lines S1, S3, S6 and S13 had some desirable horticultural traits and could be used in improving tomato crop by breeding programs or they could be considered as new breeding lines. Keywords: tomato mutants, RAPD, SSR, In vitro, yield components 1. Introduction Tomato (Solanum lycopersicum L.) is a worldwide cultivated crop, which is used both as a fresh and processed product. In the last few years, its global production has increased approximately 10% since for many countries it is a significant source of vitamins and minerals. Furthermore, it has also been recently demonstrated that it is the main source of the carotenoid lycopene, which has antioxidant properties and may help to protect against diseases, such as cancer and cardiovascular disease (Giovannucci, 1999). In Egypt, tomato is important vegetable crop which ranks first among the vegetable crops based on cultivated area (about 252 thousand hectares) and production (10.3 million tons). Tomato is suitable plant material for physiological and cytological studies due to its ease of culturing and genetic uniformity resulting from autogamy (Rick, 1980). Plant tissue culture is an important tool of biotechnology, which can be used to improve productivity of a crop via rapid availability of superior planting stock. Somaclonal variation can pose a severe threat to the genomic integrity of generated plants, which is particularly required during the genetic transformation experiments and to achieve genetic uniformity of the propagules (Soniya et al., 2001). Mutation can bring the changes at the DNA level. However, for most at the micro-propagated crops, 5% somaclonal variation is permitted (Evans, 1989). During the last four decades, significant advances have been made in the development of in vitro culture techniques, which have been extensively applied to different crop species (Harish et al., 2010; Rashid et al., 2010). The most frequently used method of regeneration in tomato is via shoot organogenesis from callus of leaf or cotyledon explants (Compton & Veilleux, 1991). The regeneration ability of a number of tomato cultivars have been tested for their ability to produce callus and shoot induction in earlier studies (Costa et al., 2000; Harish et al., 2010). Many biotechnological approaches have been focused on the improvement of tomato crop, which can grow in different agro climatic zones to meet the demands (Mandel & Sheeja, 2003). Molecular marker such as