Pistillate-parental differences and the ability to produce interspecific hybrids between Lycopersicon esculentum and 'peruvianum-complex' species (L-peruvianum and L-chilense)

To overcome the cross-breeding barriers between the cultivated tomato Lycopersicon esculentum and the 'peruvianum-complex' hybrid production ability (HPA) and pistillate-parental differences were investigated. As a criterion of HPA, the number of germinated ovules per fruit (GPF) was used. GPF was expressed as GPF = OPF x GPO, where OPF is the number of ovules per fruit, and GPO is the proportion of germinated ovules to total ovules obtained. The interspecific crossing between nine varieties and three 'peruvianum-complex' accessions revealed that the cultivars 'Sekaiichi', 'Ponde Rooza' and 'Early Pink' showed quite high and stable GPF over the years, but the cv. 'Best of All' produced no hybrids. Variance analysis for GPF, OPF and GPO, and their correlation with seven sexual organ morphological traits and three fruit morphological traits were performed. These results indicated that choosing both the pistillate parents with wider reproductive organs for high OPF and appropriate environmental conditions for high GPO might be significant for enhancing GPF in interspecific crossing.