The use of SSRs for predicting the hybrid yield and yield heterosis in 15 key inbred lines of Chinese maize

摘要

The prediction of hybrid performance is of considerable importance and has attracted much interest in maize breeding (Hallauer et al. 1988). Maize breeders have been looking for the possibility of predicting heterosis between inbred lines of maize based on the morphological, pedigree, physiological, biochemical, and molecular marker data during the past decades (Smith and Smith 1989; Smith et al. 1990; Ramesh et al. 1995). Some studies have attempted to use isozyme variation to measure genetic diversity among inbred lines and to examine the relationship between genetic diversity and grain yield heterosis (Schwartz 1960; Stuber et al. 1980; Frei et al. 1986). The relationship between isozymic diversity and hybrid yield heterosis, however, is poor because the number of isozyme loci are not abundant and may not be linked to loci that contribute to heterosis (Hadljnov et al. 1980; Lamkey et al. 1987). Therefore, it was not recognized as a good predictor of grain yield or grain yield heterosis. For the widescale application of molecular marker techniques, such as RFLP (restriction fragment length polymorphism), RAPD (random amplified polymorphic DNA), AFLP (amplified fragment length polymorphism) and SSR (simple sequence repeat) etc, considerable research is currently being conducted to determine the association of molecular marker diversity with hybrid performance and heterosis in maize. Several reports have demonstrated the high correlation between RFLP distance and hybrid performance in maize (Lee et al. 1989; Smith et al. 1990; Livini et al. 1992; Melchinger et al. 1992. Mumm and Dudley 1994; Ajmone et al. 1998), whereas Godshalk et al. (1990) and Melchinger et al. (1990) found a low correlation between them. Wu and Dai (2000) reported that correlation between genetic distance, measured by RAPD loci, and hybrid performance was generally positive and significant. After investigating 13 inbred lines of maize using AFLP and RFLP markers and assessing the relationship between genetic distance and hybrid performance, Ajmone et al. (1998) reported the correlation between AFLP markers and specific combining ability (SCA) estimates may have a practical utility in predicting hybrid performance. Microsatellites or simple sequence repeats (SSRs) are highly mutable loci that may be present at many sites in a genome (Tautz 1989; Morgante and Olivieri 1993). Recently, genetic linkage maps based on SSR markers have been constructed in maize (Chin et al. 1996; Senior et al. 1996), with the hope that it will provide an effective method for predicting hybrid performance and heterosis (Smith et al. 2000; Drinic et al. 2002).In this study, we reported the usefulness of SSRs in determination of genetic diversity among 15 elite inbred lines of maize in China and examination of the association between genetic diversity based on SSRs and both single-cross grain yields and grain yield heterosis. The possibility of prediction of yield heterosis with SSR marker was discussed.