Identification and selection of somatic hybrids obtained by protoplast fusion

Abstract

Efficient selection of hybrid plants produced by protoplast fusion is very important. Several advances have been made on the subject in recent decades. The methods used for the identification of somatic hybrids include selection by morphological characteristics (growth, leaf, stem, flower or fruit type, flower color or type of inflorescence), micromanipulation (or manual selection), flow cytometry, complementation, chromosome counting, isozyme detection and the use of molecular markers, such as random amplification of polymorphic DNA (RAPD), genomic in situ hybridization (GISH), simple sequence repeats or microsatellites (SSR), the inter-simple sequence repeats (ISSR), restriction fragment length polymorphisms (RFLP) and amplified fragment length polymorphisms (AFLP). Isozyme analysis was a very common selection method for many years. Although, molecular techniques based on DNA have become reliable methods to detect somatic hybrids. Flow cytometry offers a more rapid and sensitive method for the selection of hybrid cells. However, the equipment needed for its implementation is very expensive. Use of more than one method for early detection of somatic hybrids increases the selection efficiency. This review describes the methods used for detection of somatic hybrids and presents a list of examples on their use from 1974 on. Key words: isozymes, molecular techniques