The Ornamental Breeding Program at the University of New Hampshire (UNH) was initiated in 1998, aiming to develop new or improved vegetatively propagated cultivars. Initially, breeding focused on Anagallis monelli (Pimpernel). At the time, only one blue and one orange cultivar (`Skylover Blue' and `Sunrise') were grown commercially. Main breeding goals were to develop plants with more compact habit and earlier flowering in the spring. In 2002, the first two UNH cultivars were released as Proven Selections™: Anagallis`Wildcat Blue' and `Wildcat Orange'. We have also developed breeding lines with new pink, violet, lilac, and white flower colors that are currently in industry trials. Studies on genetics, biochemistry, and anatomy of flower color in A. monelli have been performed and molecular studies are in progress. Breeding of Nolana and Browallia started in 2000 and UNH lines are currently in industry trials. Nolana is comprised of over 80 species native to desert areas of Peru and Chile. Only two cultivars, N. paradoxa`Bluebird' and `Snowbird', and interspecific hybrid `Blue Eyes' are currently commercially available. We now have several Nolana species at UNH representing a wide germplasm base. Based on ornamental potential, some species have been selected for breeding, aiming to develop sterile interspecific hybrids. Studies to break seed dormancy to optimize germination rates are in progress, as well as research on floral development, which is being conducted in collaboration with Peruvian researchers. Interspecific hybridizations have been used in Browallia to develop breeding lines with new or improved traits than those available from seed cultivars.
Amy Douglas and Rosanna Freyre
Nolana is a diverse genus native to coastal deserts of Peru and Chile, with great potential for developing new ornamental cultivars. Low germination has been an obstacle to breeding efforts at the University of New Hampshire (UNH). Nolana fruits are comprised of unusual sclerified mericarps, each containing one or more embryos. Germination occurs with opening of funicular plugs on the mericarps. Under normal greenhouse conditions at UNH, germination success in eight Nolana species (N. adansonii, N. aticoana, N. humifusa, N. laxa, N. ivaniana, N. plicata, N. elegans, and N. rupicola) ranged from 0 to 0.05 seedlings/mericarp. We analyzed mericarp morphology, imbibition, and the effect of chemical and environmental germination treatments. SEM showed that soaking treatments create physical changes in mericarp morphology, exposing tracheid tubes in the funicular plugs. Mericarps were soaked in dye to track imbibition, confirming that this occurs through the tracheid tubes, and that additional scarification is not required. The following chemical treatments were unsuccessful in increasing germination: 0.1 N HNO3, 0.2 KNO3, conc. H2SO4, 10 mM or 1 μM ethephon. Gibberellic acid (1000 ppm) effectively increased germination in some species (up to 0.47 seedlings/mericarp). Mericarps stored dry for 2 years had significantly higher germination than fresh mericarps (0.55 seedlings/mericarp). Mericarps of N. aticoana were subjected to after-ripening treatments. Mericarps stored for 7 weeks at 35 °C and 75% RH showed significantly higher germination (0.36 seedlings/mericarp) than mericarps stored dry, or stored moist for 1-6 or 8-12 weeks. Our findings facilitate development of larger hybrid populations, thus increasing the efficiency of Nolana breeding programs.
Rosanna Freyre and Erin Tripp
The potential for natural hybridization to occur between non-native, invasive species and closely related native species is of interest to biologists, conservationists, and land managers, particularly in regions such as the southeastern United States where numerous non-native species have become serious environmental pests. To explore this potential between the invasive plant species Ruellia simplex and the closely related, sympatric Ruellia caroliniensis, we conducted a study of reproductive crossability and hybrid viability. Results indicate that the production of interspecific hybrids is possible, but only in one direction (i.e., with R. caroliniensis as the maternal parent). Artificial hybrids were weak, slow-growing, and sterile. These data suggest that it is unlikely that R. caroliniensis × R. simplex hybrids could invade the gene pool of native R. caroliniensis. We also characterized hybrids at the molecular level by sequencing parents plus F1 progeny for the nuclear ribosomal internal transcribed spacer (ITS) + 5.8S region. All hybrid genotypes formed a strongly supported clade with the maternal parent, Ruellia caroliniensis. Within this clade, hybrid individuals were not differentiable from maternal genotypes. We then examined general plant morphology of hybrid individuals and the two parents. Unlike results from the molecular characterization, there was a strong signal of hybrid intermediacy from this morphological work. We conclude that morphology but not molecular sequence data (from nrITS) can be used to distinguish the two parents and their F1 hybrids.
Rosanna Freyre and Robert J. Griesbach
Plants of Anagallis monelli in their native habitat or in cultivation have either blue or orange flowers. Clonally propagated cultivars, seed obtained from commercial sources and the resulting plants were grown in a greenhouse at the University of New Hampshire. F2 progeny obtained from hybridization between blue- and orange-flowered plants had blue, orange or red flowers. There were no significant differences in petal pH of orange-, blue-, and red-flowered plants that could explain the differences in flower color. Anthocyanidins were characterized by high-performance liquid chromatography. Results indicated that blue color was due to malvidin, orange to pelargonidin, and red to delphinidin. Based on our segregation data, we propose a three-gene model to explain flower color inheritance in this species.
Rosanna Freyre and Sandra B. Wilson
Rosanna Freyre and J. Brent Loy
Five tomatillo (Physalis ixocarpa Brot. ex Hornem) cultivars available from commercial seed companies (`De Milpa', `Puebla Verde', `Purple Tomatillo', `Tomatillo' and `Toma Verde') and four Physalis L. accessions (PI 197691, PI 270459, PI 291560, and PI 309812) were grown in 1997 and 1998 at Kingman Research Farm, Durham, N.H. Three manual harvests per plot were performed each year, recording data of total fruit weight, number of fruit and average fruit weight for each genotype. There were statistically significant differences between tomatillo genotypes for all three traits. Statistically significant differences between the 2 years were found for fruit number and average fruit weight per genotype. Over both years, total fruit weight varied from 29.7 to 63.7 t·ha-1 (13.3 to 28.4 ton/acre). Fruit numbers per plant varied from 83 to 330, and average fruit weight varied from 18.0 to 38.3 g (0.6 to 1.3 oz). PI 197691 and PI 270459 performed better than some of the commercial cultivars indicating their potential to be used as germplasm for breeding. A basket-weave trellising system which kept plants upright was tested. This made harvest easier and potentially can be used for tomatillo culture.
Rosanna Freyre, Zhanao Deng, and Victor A. Zayas
Rosanna Freyre, Amy C. Douglas, and Michael O. Dillon
Reciprocal crosses, both intraspecific and interspecific, were made among five Chilean species of Nolana (Solanaceae), a genus native to western South America. With the exception of N. paradoxa, plants of all species used were grown from mericarps collected from wild populations. Self-pollinations were generally not successful, suggesting obligate allogamy. A total of 333 hybridizations were performed, of which 109 were intraspecific and 224 interspecific. Successful intraspecific hybridizations, as measured by formation of fruits, were produced for N. acuminata (83%), N. elegans (94%), N. paradoxa (82%), and N. rupicola (100%), however viable hybrids were only obtained for N. paradoxa. Interspecific combinations resulted in over 80% fruit set, however, viable hybrid success ranged from only 1% to 5%. Crosses included N. elegans × N. paradoxa with 20 viable hybrids, N. paradoxa × N. elegans with two hybrids, N. paradoxa × N. rupicola with seven hybrids, and N. rupicola × N. paradoxa with five hybrids. Exceptions included crosses involving N. aplocaryoides, with up to 20% fruit set. Also, the combination N. paradoxa × N. aplocaryoides with five hybrids, had a 26% success. All interspecific hybrids obtained had N. paradoxa as one of the parents, which could be related to artificial selection for high germination frequency.
Rosanna Freyre, Adam Moseley, Sandra B. Wilson, and Gary W. Knox
Mexican petunia (Ruellia simplex Wright) is a non-native plant that was introduced to Florida sometime in the 1940s and since then has naturalized in most of the state and in other southern states. Since 2007, we have developed at the University of Florida/Institute for Food and Agricultural Science in Gainesville the first Ruellia L. breeding program aiming to develop fruitless plants with different flower colors and growth habits that will not be invasive by seed dispersal. A combination of polyploidization and hybridization methods was used. In 2011, a total of 15 plants were selected and grown in southeastern, north–central, and northwestern Florida (Fort Pierce, Citra, and Quincy) using a randomized block design with three blocks and three plants per plot at each site. Plants were evaluated monthly for landscape performance, flowering, and fruiting. Two hybrids (R10-102 and R10-108) had outstanding potential as new fruitless cultivars for the plant industry having improved landscape performance and flowering.
Andrea Quintana, Rosanna Freyre, Thomas M. Davis, and Robert J. Griesbach
Wild Anagallis monelli exhibits blue or orange flower colors in geographically isolated populations. A new red flower color was developed through breeding, and a three-gene model was proposed for the inheritance of flower color in this species. In this study, blue and orange wild diploid accessions were used as parents to develop six F2 populations (n = 19 to 64). Sexual compatibility between blue and orange wild individuals was low with only 29% of the hybridizations producing F1 individuals. Six of 14 cross combinations between F1 siblings produced fruits, and fruiting success ranged from 55% to 90%. The number of seeds per fruit averaged 14.1 and germination rates for the F2s were low (16.8% to 30.7%). In three of six F2 populations obtained, flower color segregation ratios for orange, blue, and red were not significantly different from the expected ratios under a previously proposed three-gene model. White flower color was obtained as a fourth color variant in two of the remaining F2 populations. For one of these populations, segregation ratios were not significantly different from expected ratios for an expanded four-gene model. White flowers did not contain anthocyanidins, suggesting that there was a mutation in the early stage of the anthocyanin pathway. Orange flower color was found to be primarily the result of pelargonidin, blue to malvidin, and red to delphinidin. These three pigments may be present simultaneously, and their ratios play a significant role in determining flower color. Other factors such as copigments, metal ions, or a different molecular conformation of the anthocyanin could also be involved in flower color determination.