A COMPARISON BETWEEN IN VITRO CULTURE OF TWO TOMATO PARENTAL LINES AND THEIR RECIPROCAL HYBRIDS

Two tomato parental lines. Red Cloud (RC) and a local cultivar (L), were reciprocally crossed. The regenerating abilities of the parental lines and the hybrids were compared through shoot-tip culture. Prior to in vitro culture, some morphological characteristics of the two tomato reciprocal hybrids (RCxL) and (LxRC) and their parents were evaluated. In iw vitro culture, the effects of five concentrations of benzyl adenine (BA) and kinetin (K) and four cultures, (one original and three subcultures) were examined on the tomato parental lines and the hybrids. The effects of indolebutyric acid (IBA) and naphthaleneacetic acid (NAA) concentrations on root initiation of two parental lines and the hybrids were also evaluated. Heterosis was observed in the hybrids compared to the parents for vigor, yield and some qualitative traits. BA affected callus and shoot formation more than K. Local x RC had the highest callus fresh weight on media containing BA and K whereas RCxL hybrids produced more shoots compared with LxRC and the parents. Both hybrids needed lower levels of BA than did the parents and required lower levels of K compared with RC parent. Among various lines, LxRC hybrids heeded the lowest levels of BA and K. Number of shoots in RC was decreased by subcultures. However, shoot numbers in local parents and two hybrids increased in subsequent subcultures. Generally, NAA produced more fresh and dry root weight in two parental lines and their hybrids. The growth regulators IBA and NAA induced long, thin, white and short, thick, brown roots, respectively. All four lines produced suitable roots on media containing IBA, and were transferred to soil successfully.