Euphytica 103: 223–226, 1998. © 1998 Kluwer Academic Publishers. Printed in the Netherlands. 223 Determination of F 1 hybrid seed purity in pepper using PCR-based markers Jordi Ballester & M. Carmen de Vicente ∗ Institut de Recerca i Tecnologia Agroaliment` aries (IRTA), Departament de Gen` etica Vegetal, Carretera de Cabrils, s/n. 08348-Cabrils, Spain; ( ∗ author for correspondence) Received 15 August 1997; accepted 17 April 1998 Key words: Capsicum annuum, hybrid purity, RAPDs, SPARs Summary We present the potential use of two kinds of PCR-based markers, RAPDs (Random Amplified Polymorphic DNA) and SPARs (Single Primer Amplification Reactions), as tools for hybrid seed purity determination. Five F 1 pepper hybrids (Capsicum annuum L.) and their parents were analyzed with 100 10-mer primers and 10 nucleotide repeat primers. We found at least one useful marker for testing the purity of all hybrids studied. Despite their dominant inheritance these markers could be an efficient implement in the process of quality testing of hybrid seeds. Introduction To determine hybrid seed quality, companies need quality controls. These controls are conceived to verify that 1) the designated cross occurred, 2) the number of self or sib-pollinations between plants of the fe- male parents meets the necessary purity required by law, 3) the product has an adequate quality (vigor and viability). For years the method used to check hybrid seed purity has been the grow-out test. This consists of growing a representative sample of the F 1 seed and later classifying it using descriptors of differences as true hybrid seed or off-types. This method is time con- suming, space demanding and often does not allow the unequivocal identification of genotypes. Isozymes and restriction fragment length polymor- phisms (RFLPs) have been used for testing hybrid purity (Tanksley & Jones, 1981; Arús et al., 1985; Livneh et al., 1990). Both techniques are useful but have different drawbacks: often an insufficient num- ber of developed isozyme systems are available for a particular species and, on the other hand, RFLPs have the limitation of their cost and complexity for routine commercial testing. The advent of the Polymerase Chain Reaction (Saiki et al., 1987) had a direct impact on the devel- opment of new markers more suited to plant breeding related practices. In recent years, an increasing num- ber of PCR-based techniques have emerged which are proving useful for breeding applications (Staub et al., 1996). The use of these markers follows a simple and fast procedure, needs a low quantity of DNA and is easily automated. RAPD (Williams et al., 1990) uses the PCR with non-specific primers to amplify random DNA fragments. The single primer amplification re- action (SPAR) is a different approach that uses also one primer based on a simple sequence repeat (SSR) and amplifies inter-SSR DNA sequences (Gupta et al., 1994). The cultivated pepper is known as possessing very little genetic diversity; however, some authors have pointed out that it does not seem to be as narrow as for other crops (Heiser, 1979). In a recent publication, 17% of the probes used in a RFLP study (with one enzyme) of the genus Capsicum succeeded to differ- entiate four C. annuum varieties, and the same did 12% of RAPD PCR primers (Prince et al., 1995). In a different report (Lefebvre et al., 1993), 14% of RFLP probes (with 10 restriction enzymes) distinguished six out of 13 varieties of C. annuum. In spite of that, it is general knowledge that commercial varieties, and particularly hybrid varieties of vegetable crops, are based on increasingly narrower variation at the genetic level. In consequence, discriminating between elite