Reproductive biology and crossbreeding in Physalis species

There is a scarcity of studies aimed at the development of Physalis genotypes. For a breeding program to start, it is necessary to know the reproductive biology of the species that will be used in the crossings. The objective was to evaluate the pollen viability, stigmatic receptivity and the compatibility of self-pollinations and interspecific crossings between the species Physalis angulata, P. ixocarpa, P. pruinosa, P. peruviana, P. pubescens, P. minimum, and P. daturifolia. One access of each species was used. The plants were grown in a greenhouse. To determination the viability of the pollen grains, they were distributed in Petri dishes containing the specific culture medium. The stigmata receptivity assessment in pre-anthesis was carried out every two hours, from 6:00 am to 6:00 pm, for three days using 3% drops of hydrogen peroxide (H2O2). In sequence, all species were crossed with each other acting as pollen donors and recipients. The self-pollination was also performed. The species P. ixocarpa had the highest percentage of pollen grains germinated in vitro (75.30%), followed by the other species that had viability between 60.10% and 43.60%. The best receptivity of the stigma for the species P. angulata was at 8:00 am, 10:00 am and 12:00 pm; for the species P. ixocarpa at 10 am; to P. pruinosa at 6:00 am, 8:00 am, 10:00 am and 12:00 pm; for P. peruviana at 10 am and 12 pm; to P. pubescens at 4:00 pm; for P. minimum at 12:00, 14:00 and 16:00; and for P. daturifolia at 12:00 and 14:00. There was fruit fixation in most interspecific combinations, except for P. daturifolia as a pollen donor for P. minimum and P. pubescens. The same aspect occurred when pollen from P. peruviana was combined with P. pruinosa and also by the combination of P. pruinosa with P. daturifolia. There was self-compatibility in all Physalis species explored. All species had pollen grains viability, stigma receptivity in pre-anthesis, all Physalis species were self-compatible and there was fruit fixation for most interspecific combinations.