Characterization of tetraploid plants regenerated via protoplast culture of Iris fulva and their crossability with Japanese irises

Characteristics such as flower form, size and color of outer and inner perianths, anthocyanins in outer perianths, size, color and fertility of pollen and self-fertility of diploid and tetraploid lines regenerated via protoplast culture of Iris fulva were examined and compared with those of the diploid wild line. Among these characteristics, flower form, inner and outer perianth sizes of the tetraploid lines were noticeable, because these lines had upward flower forms and bigger flowers than diploid lines. Furthermore, reciprocal crosses between diploid or tetraploid lines of I. fulva and I. ensata and those of I. fulva and I. laevigata were performed. Three seedlings were obtained from the cross of tetraploid I. fulva × diploid I. laevigata through embryo rescue. One of them was identified as the interspecific hybrid between tetraploid I. fulva and I. laevigata by flow cytometoric (FCM), cytological and molecular (RAPD) analyses. This is the first report on production of hybrids from these lines. I. fulva has unique brown flowers, and this trait could be very useful for flower color breeding of I. laevigata which lacks this color. Therefore, the hybrid of I. fulva (4×) × I. laevigata may be the best available gene source for brown color breeding of this species.