Interspecific Crossability of Selected Salvia Species and Potential Use for Crop Improvement

Abstract

The wide diversity in the genus Salvia represents an untapped genetic resource to improve and diversify Salvia grown as floriculture crops. Interspecific hybrids have formed naturally or by chance hybridization of cultivated plants, but the degree to which species are cross-compatible is largely unknown. The crossability of nine Salvia species selected to cover a wide range of the diversity in European and American species was evaluated in a full diallel mating scheme. Overall, crossability of the selected species was low with only five of 72 interspecific cross combinations producing viable seed, whereas all nine species were self-fertile. Successful crosses were mostly within close phylogenetic groupings. The majority of successful crosses were between species with different chromosome numbers, suggesting that chromosome number differences alone are not a major barrier to hybridization in this genus. A Salvia nemorosa × Salvia transslyvanica F2 population exhibited transgressive segregation for several horticulturally important traits, including flower size, plant height, and time to flower. Plant height was correlated positively with flower length, inflorescence branch number, and time to flower. Time to flower was correlated positively with flower length. Individuals with desirable trait combinations were identified within the population.