Climate warming has not affected day and night symmetrically: daily temperature range (DTR) is narrowing, as daily average temperature (DAT) increases. The potential impacts of combined DAT and DTR variation on plants are unknown. Four experiments were conducted to assess such impacts. In the first two, plants of seven herbaceous perennial taxa were exposed to 18 combinations of day and night temperature for 50+ days. Effects on total plant dry weight (DW) were analyzed with the aid of a thermodynamic model, modified to include two temperature dimensions. Results showed that the effects of temperature on DW cannot be accounted for by variation in either DAT or DTR alone, and that their magnitude is equivalent. The greatest effect of variation in DTR on DW was on plants growing closest to their optimal DAT. Time?to?event data analysis methods were used to determine the relative effects of DAT and DTR on anthesis and death in two taxa. Effects of day and night temperature could be separated for both events, but were almost entirely subsumed into DAT. Although effects of DTR were significant, they only became meaningful at the extremes. Results suggest changes in DTR are a lesser concern for anthesis and survival than for gross productivity. Two experiments were then conducted to assess the effect on DW of temperature variation within each of the two phases of the diurnal cycle. Plants of Delphinium × cultorum and Rudbeckia fulgida var. sullivantii L. were grown for 40 days under 28 temperature regimes all resulting in cycles of 12-h days/12-h nights at average either 15/15°C, or 25/15°C. There were 14 regimes for each combination, during which temperature varied between 5 and 35 °C every 4 hours. Temperature varied during the light period in the first experiment, and the dark period in the second. Few significant differences in DW were found among regimes for either taxon, and they did not produce a consistent pattern. Results indicate that over season?long durations, effects of sub?diurnal variation on gross productivity are far less consequent than those of diurnal variation.

Herbaceous perennials are planted worldwide in public gardens, and commercial and home landscapes. Little research based information exists on response of herbaceous perennials to fertilizer nitrogen (FN) rate and timing and the potential for loss of applied N via leaching. Therefore, we constructed simulated landscapes and installed canna lily (Canna L. 'President'), coreopsis (Coreopsis verticillata L. 'Moonbeam' ), purple coneflower (Echinacea purpurea L. 'Magnus'), iris (Iris siberica L. 'Caesar?s Brother'), switchgrass (Panicum virgatum L. 'Shenandoah'), sedum (Sedum L. 'Herbstfreude'), and sage (Salvia x sylvestris L. 'East Friesland') to determine how FN rate and timing affected growth and performance of herbaceous perennials and potential N leaching. Porous ceramic cup lysimeters were installed in situ in each landscape plot 38 cm below the soil surface to examine the effects of FN rate and timing on soil solution N concentrations. The experiment was a 4 x 4 factorial in a randomized complete block design with four replications. Four rates of FN: 0, 7, 14, and 28 g?m-2 N were divided equally into two applications and applied at the following times: 1) winter (Jan. 15 and Feb.15), 2) spring (Apr. 15 and May 15), 3) summer (June 15 and July 15), or 4) fall (Sept. 15 and Oct.15) beginning 2001. Soil solution samples were collected approximately every 2 weeks from Jan. 30, 2002 to Nov. 3, 2003 and analyzed to determine soil N (NO3- and NH4+) concentrations. Data collected in 2002 and 2003 for each species included the following number of flowers, plant visual evaluations, growth index (GI), and top dry weight. In 2003, mineral nutrient concentration was determined for each species. Plant response to treatments varied in 2002 and 2003. Our results indicated that despite statistical significance differences, many differences were small and FN treatments had little impact on the growth and ornamental qualities of these species. However, applying no N may not advisable, as some perennials species did benefit from an FN application during a specific time. Soil N concentrations remained above 10 mg?L-1 for 110 days, 62 days, 52 days, and 192 days when applied during January/February, April/May, June/July, 2002 and September/October in 2001 respectively. In 2003, soil N concentrations from FN rates of 7 g?m-2 N (1.5 lbs?1000 ft-2) and 14 g?m-2 N (3.0 lbs?1000 ft-2) applied in January/February, June/July, April/May and September/October remained below 10 mg?L-1 until the end of the study (Oct. 14, 2003). Nitrogen concentrations increased to 19 mg?L-1, 38 mg?L-1, and 21 mg?L-1, after 28 g?m-2 N (6.0 lbs?1000 ft-2) was applied in January/February, April/May, and June/July, respectively. To cover the needs of a wide variety of perennial species that usually exists in one landscape as well as minimize N concentrations in the soil solutions, we recommend a low to moderate rate of FN (5 g?m-2 to 15 g?m-2 ) be applied in split applications in spring and early fall.

The watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus] is a major vegetable crop in the United States. The genetics of this crop have been widely studied and several genes reported. Nevertheless, further investigation was needed for genes determining the appearance of the fruit (rind and flesh colors), the weight of single fruit, and resistance to gummy stem blight, a severe disease of watermelon caused by Didymella bryoniae (Auersw.) Rehm. In this work the inheritance of novel rind phenotypes was measured and the genetics of flesh color verified. Three new genes were identified: Dr for the deep-red flesh color of 'Dixielee' and 'Red-N-Sweet', Yb for the yellow belly of 'Black Diamond Yellow Belly', and is for the intermittent stripes of 'Navajo Sweet'. The spotted phenotype from 'Moon and Stars' was transferred to light green and gray cultivar for the development of novel varieties with distinctive rind patterns. Yield of 80 diverse cultivars was evaluated in replicated experiments. Some of the new, elite hybrid cultivars were in the top yielding group, however old, inbred cultivars appeared in the top group as well. Consistent and significant differences among the 80 cultivars tested suggests genetic variation for yield. Since most watermelon consumers are interested in smaller fruit, six adapted cultivars bearing the largest and smallest fruit were crossed in a half-diallel, producing F1, F2, and backcross generations. Genotypic variances, heritability, and gain from selection were estimated. High environmental variance and low narrow- and broad-sense heritability were recorded. Finally, the inheritance of resistance to gummy stem blight, previously attributed to the db gene, was verified. A genetic system more complex than a single gene seems to regulate the transmission of resistance from resistant to susceptible germplasm. Due to the complexity of phenotypic testing for this disease in watermelon, a new project for the development of molecular markers linked to resistance was initiated. Nevertheless, the use of F3 phenotypic data and F2 genotypic markers and the apparent complexity of the trait did not allow the identification of a tightly linked marker.

The development of organic and conservation tillage-based vegetable production systems will offer growers in the southeastern United States new economic opportunities and promote resource conservation. The purpose of this research project was to assess the impact of incorporating a summer crop that serves as both cover crop and marketable hay crop in an organic fall vegetable production system. Sorghum sudangrass [Sorghum bicolor (L.) Moench X S. sudanense (Piper) Staph] is commonly cultivated as a forage crop in the Southeast and has the potential to produce abundant biomass, suppress weeds, and decrease soil compaction as a summer cover crop. Field studies were conducted to determine the effects of sorghum sudangrass cutting frequency and biomass removal as hay on cover crop biomass production, weed suppression by cover crop residues, and cover crop re-growth in a subsequent cabbage (Brassica oleracea L. var. capitata) crop under conventional and no-till management. Field and greenhouse studies were undertaken to identify potential negative interactions between cover crop residues and cabbage transplants. Transplant dry weight and head weight of the indicator species, cabbage, were used to assess the impact of cover crop management and tillage system on crop growth and development. Results suggest that a sorghum sudangrass hay crop can be harvested without compromising weed suppressive qualities of the cover crop. In this study, however, the presence of sorghum sudangrass led to reductions in cabbage transplant growth and head weight. Sorghum sudangrass may not be suitable as a cover crop immediately prior to conventional or no-till fall vegetable production due to its propensity to re-grow and allelopathic potential.

Multiple projects were conducted to investigate the potential for developing a breeding program utilizing species of <i>Catalpa</i> Scop. and <i>Chilopsis</i> D. Don. The efficacy of oryzalin was evaluated for inducing polyploidy and restoring fertility in the sterile, intergeneric hybrid ×<i>Chitalpa tashkentensis</i> Elias & Wisura [<i>Catalpa bignonioides</i>Walt. x <i>Chilopsis linearis</i> (Cav.) Sweet] 'Pink Dawn'. Submerging meristems in 150 µM oryzalin for up to 24 hours was effective at inducing tetraploids and cytochimeras. Pollen from the diploid cultivar was non-viable, but pollen from the polyploid stained and germinated as well as pollen from progenitor taxa. Polyploid ×<i>Chitalpa</i> were self-compatible yielding tetraploids when self pollinated and triploids when crossed with <i>C. bignonioides</i>, but reciprocal crosses with <i>Chilopsis</i> taxa failed. To increase recovery of triploids, we investigated germination of ovules and embryos at various harvest dates on Schenk and Hildebrandt (SH) basal salts supplemented with various medium components. Germination of triploid [(polyploid ×<i>Chitalpa</i>) x <i>C. bignonioides</i>] and tetraploid (selfed polyploid ×<i>Chitalp</i>a) embryos was greatest at 7 weeks after pollination on SH with 20 g·L^-1 sucrose and ≥ 1 µM gibberellic acid (GA₃). Triploids [<i>Chilopsis linearis</i> x (polyploid ×<i>Chitalpa</i>)] germinated < 5%. Additional studies were conducted to screen diverse taxa for resistance to powdery mildew (PM), <i>Erysiphe elevata</i> (Burr.) U. Braun & S. Takam, and catalpa sphinx larvae (CSL), <i>Ceratomia catalpae</i> (Boisduval). Twenty-four taxa from <i>Catalpa</i> (section <i>Catalpa</i> Paclt and <i>Macrocatalpa</i> Grisebach), <i>Chilopsis</i>, and ×<i>Chitalpa</i> were screened in 2004-05 for susceptibility to PM. Disease incidence and severity were recorded to calculate area under the disease progress curves (AUDPC) for each year. North American <i>Catalpa</i> spp. in sect. <i>Catalpa</i>, <i>Chilopsis</i>, and ×<i>Chitalpa</i> taxa were all moderate to highly susceptible to PM. Chinese <i>Catalpa</i> spp. in sect. <i>Catalpa</i> and West Indian sect. <i>Macrocatalpa</i> were resistant to PM. Hybrids among North American and Chinese <i>Catalpa</i> spp. in sect. <i>Catalpa</i> varied in susceptibility, indicating inheritance of partial resistance to PM. A no-choice feeding study conducted with CSL in 2005 found no differences in survival or growth of larvae reared on taxa from both sections of <i>Catalpa</i>, <i>Chilopsis</i>, and ×<i>Chitalpa</i>. Future breeding of ×<i>Chitalpa</i> can utilize the identified sources of resistance for PM; however, a source of resistance to CSL was not found. Triploids are generally infertile and may be deployed by breeders to limit invasive potential of introduced ornamentals. However, inheritance of ornamental traits can be complex at higher ploidy levels. Inheritance of two mutant foliage types, variegated and purple, was investigated for diploid, triploid and tetraploid tutsan (<i>Hypericum androsaemum</i> L.). Fertility of progeny was evaluated with pollen viability tests, percent fruit set, and germinative capacity of seed from specific crosses. Segregation ratios were determined for diploids in reciprocal di-hybrid F₁, F₂, BC_1P1, and BC_1P2 families and selfed F₂s with the parental phenotypes and triploid and tetraploid F₂s. Diploid di-hybrid crosses fit the expected 9:3:3:1 ratio for a single, simple recessive gene for both traits, with no evidence of linkage. A novel phenotype representing a combination of parental phenotypes was recovered. Data from backcrosses and selfing also supported the recessive model. Both traits behaved as expected at the triploid level; however, at the tetraploid level the number of variegated progeny increased, with segregation ratios between random chromosome and random chromatid assortment models. We propose the gene symbol <i>var</i> (<i>variegated</i>) and <i>pl </i> (<i>purple leaf</i>) for the variegated and purple alleles, respectively. Triploid pollen stained moderately well, but pollen germination was low. Triploid plants demonstrated extremely low male fertility and no measurable female fertility (no viable seed production). Research presented herein demonstrates the feasibility of manipulating ploidy levels for breeding desirable ornamental traits including non-invasiveness.

A series of studies were conducted with eastern redbud (<i>Cercis canadensis</i> L.) to identify clones with rooting potential, determine the optimum growth stage for taking stem cuttings, investigate the effect of auxin treatment on rooting of stem cuttings, and determine optimum nitrogen (N) nutrition for seedlings grown in containers. The first study consisted of two experiments, one utilizing softwood cuttings and the other semi-hardwood cuttings, to investigate the influence of growth stage and auxin treatment on rooting of four related clones of eastern redbud. The clones were âFlameâ, dwarf white, and two selections (NC99-6-1 and NC99-6-2) of an F1 generation of a cross of âFlameâ and dwarf white. At each growth stage, rooting responses of the clones varied and were influenced greatly by auxin treatment, demonstrating the variable rooting potential of the genotypes. In both experiments, âFlameâ rooted well [63% rooting in the softwood experiment when treated with the potassium (K) salt (K-salt) of indolebutyric acid at 5000 mgâ¢L^-1(ppm), 83% rooting when treated in the semi-hardwood experiment with K-IBA at 10,000 mgâ¢L^-1]. For the softwood cutting experiment, cuttings of dwarf white (46%) and NC99-6-2 (75%) rooted best when treated with K-IBA at 15,000 mgâ¢L^-1. Softwood cuttings of NC99-6-1 rooted most successfully (46%) when treated with K-IBA at 10,000 mgâ¢L^-1. Dwarf white and the F1s rooted poorly in the semi-hardwood experiment. In the second study, stem cuttings of four popular clones of eastern redbud (âAce of Heartsâ, âAppalachianâ, âForest Pansyâ, and âHearts of Goldâ) were taken on seven dates following budbreak during Spring and Summer 2007 and evaluated for rooting potential. Rooting was affected by a clone x cutting date interaction, indicating the optimum time to take cuttings was different for each clone. Cuttings of âAce of Heartsâ taken 6 weeks after budbreak (WAB) rooted at 75% and 71% when treated with K-IBA at 5000 mgâ¢L^-1 and 15,000 mgâ¢L^-1, respectively. In contrast, cuttings of âAppalachianâ rooted at 96% and 93% when taken 15 WAB, the last date tested for that clone, and treated with K-IBA at 5000 mgâ¢L^-1 and 15,000 mgâ¢L^-1, respectively. When taken 8 WAB and treated with K-IBA at 5000 mgâ¢L^-1 or 15,000 mgâ¢L^-1, cuttings of âHearts of Goldâ rooted at 42% and 58%, respectively. Cuttings of âForest Pansyâ rooted poorly no matter when they were collected or the K-IBA treatment. In the final study, containerized seedlings of eastern redbud were grown in a greenhouse for 10 weeks with N application rates (NARs) ranging from 0 to 300 mgâ¢L^-1. Seedlings fertilized with N at 180 mgâ¢L^-1 had the greatest leaf area, leaf dry weight, and total dry weight. Plants allocated more resources to root growth at NARs < 60 mgâ¢L^-1. At NARs ⥠60 mgâ¢L^-1, allocation of carbohydrates to roots and tops was constant, with a root:top ratio of 0.25. Foliar concentrations of nitrogen and phosphorus increased linearly with increasing NAR while concentrations of potassium were not affected by NAR.

Late blight, caused by the oomycete Phytophthora infestans (Mont.) de Bary, is a destructive disease of tomato worldwide. Originating in the highlands of central Mexico, through migration, mutation, and sexual recombination, this pathogen has proven mobile and highly variable. Three monogenic R genes (Ph-1, Ph-2, and Ph-3) for resistance to late blight have been identified in tomato. However, P. infestans isolates which overcome each of these individual R genes have been documented. The objectives of this research were to characterize the inheritance of late blight resistance in the home garden tomato 'Richter's Wild Tomato', to determine if this resistance is allelic to any of the three previously identified resistance sources, and to evaluate late blight resistance of R gene F1 hybrid combinations relative to individual R genes. 'Richter's Wild Tomato' was crossed with NC215E-1, a late blight susceptible fresh market breeding line, and evaluation of derived BC1F2, BC2F2, and BC3F1 populations indicated single gene inheritance of late blight resistance. Evaluation of an F2 population derived from the cross 'Richter's Wild Tomato' x 'Legend' (Ph-2) indicated that the monogenic resistance conferred by 'Richter's Wild Tomato' was allelic to Ph-2. Combinations of Ph-2, either from 'Richter's Wild Tomato' or 'Legend', and a fresh market line possessing Ph-3 displayed superior resistance versus individual R genes and other R gene combinations in North Carolina field trials under natural inoculation. Combined resistance has the potential to not only provide a superior level of resistance, but to also be more stable over time.

Japanese stiltgrass is a nonnative invasive grass that occurs in many habitats and is a management concern throughout the eastern United States. Experiments were conducted to address biological and ecological considerations for effective management of Japanese stiltgrass and restoration of native plant communities. Conventional management recommendations emphasize Japanese stiltgrass removal in autumn prior to flowering. Investigations of Japanese stiltgrass reproductive biology were conducted to assess biological considerations that impact such management strategies. Japanese stiltgrass was grown in long day growth chambers (26/22 C) and plants were moved 2, 6, or 10 wk after germination to short day growth chambers (26/22 or 22/18 C). All plants exposed to short days flowered, while under long days no plants flowered. No difference in inflorescence number or shoot dry weight was observed between the two temperature regimes. Japanese stiltgrass populations from North Carolina, Pennsylvania, and Virginia flowered similarly in response short day conditions. Furthermore, inflorescences from natural stands of Japanese stiltgrass were harvested four times; one raceme branch beginning to emerge through the leaf sheath, one raceme branch fully elongated and a second branch visible, fully expanded inflorescence, and in concert with natural dispersal. Following > 90 d storage, seed germination from each harvest averaged 13, 51, 95, and 100%, respectively, suggesting management designed to prevent seed production should be implemented before flowering. In forested areas, herbicides that selectively control Japanese stiltgrass while preserving native vegetation may be desired. The efficacy of three selective postemergence herbicides (fenoxaprop-P, imazapic, and sethoxydim) applied early, mid-, or late season were compared. The herbicides, averaged across application timings, controlled Japanese stiltgrass 83 to 89% and reduced seedhead production 79 to 94%. Seedling emergence was reduced 89, 70, and 78% in spring 2004 by fenoxaprop-P, imazapic, and sethoxydim, respectively, applied in 2003. Additionally, fenoxaprop-P or sethoxydim applied twice (4 wk interval) at half-label or full labeled rates controlled Japanese stiltgrass, providing 92% reduction in biomass and 97 to 98% seedhead reduction. Experiments were conducted to determine if Japanese stiltgrass seeds possess dormancy and if so, to determine conditions required to overcome dormancy and for successful germination. Mature Japanese stiltgrass seeds were collected in autumn 2002 and 2003, cold stratified moist at 4 C or stored dry at 21 C, 0 to 90 d. After storage, seeds were incubated in petri dishes in alternating or constant temperatures and exposed to 14 h or 0 h (total dark) photoperiod. Less than 1% of seeds stored 0 or 15 d germinated while > 95% of seeds stored 90 d germinated, suggesting primary innate dormancy upon natural dispersal. A three-year experiment was conducted in two forest sites to document the ecological impacts of conventional and alternative selective management on Japanese stiltgrass populations and native flora recruitment and establishment. Conventional management treatments included hand-pulling, mowing, or glyphosate (1.1 kg ai/ha) applied in autumn compared to hand-pulling or fenoxaprop-P (0.19 kg ai/ha) applied as needed throughout the season. All management treatments significantly reduced Japanese stiltgrass cover and seed bank over time compared to no management and decreases in relative Japanese stiltgrass cover and seed bank populations were greater in 2004 than 2003, after two seasons of management. However, selective management was more suitable than nonselective management or no management for recruitment and re-establishment of native plants and increasing overall species richness. Additionally, relative cover of other exotic plants decreased 6% over time, suggesting that removal of Japanese stiltgrass did not increase invasion of other exotic plant species.

In 2004, North Carolina supplied 46% of the nations' sweetpotato and generated 79 million dollars for the state but of the 16,000 ha in production that year; only 405 ha were managed according to federal organic standards. A three-year field experiment was initiated in 2001 to evaluate organic sweetpotato ?Beauregard? production systems that varied in cover crop management and tillage. Three organic systems including 1) compost and no cover crop with tillage (Org-NC), 2) compost and cover crop incorporated prior to transplanting (Org-CI), and 3) compost and cover crop with reduced tillage (Org-RT) were compared to a conventionally managed tilled and chemical control (Conv) production system using a randomized complete block design with six replications. All sweetpotato tissue macro and micronutrient concentrations were within sufficiency ranges defined by North Carolina Department of Agriculture & Consumer Services. Sweetpotato N (4.6%), P (0.5%), and K (4.3%) tissue concentrations were greater in Org-CI compared to remaining systems at 60 DAP in 2004. Monocot and dicot weed density and biomass were similar between Org-NC and Org-CI each year, and with few exceptions were similar to Conv. In Org-RT, high monocot weed density limited sweetpotato vine above ground biomass (154 g m^-2) and total yield 11.2 Mg ha^-1) in 2002. In 2001, the percentage of No. 1 grade roots was at least 19% greater in Org-CI (65 %) and Org-NC (62 %) than Conv (50 %). In 2002, the percentage of No. 1 roots was similar among Org-CI (74 %), Org-NC (71 %) and Conv (67 %) and similar among systems in 2004. Root quality was assessed based on degree of insect damage by wireworm-Diabrotica-Systena (WDS) complex. In 2001, Org-RT had the highest percentage of marketable roots (68 %) compared to remaining systems (19-43 %). The number of marketable roots was similar among systems in 2001 and 2004, but reduced in Org-RT (1.3 Mg ha^-1) compared to remaining systems. Means of wireworm (Melanotus and Conoderus spp.) densities per trap were significantly correlated with degree of root damage. Overall, organic systems performed as well as the conventionally managed system in at least one or more areas.

Studies were conducted in order to develop a fertile form of the azaleodendron cultivar Rhododendron L. ?Fragrant Affinity? and determine parentage of this and two other azaleodendron cultivars. Wide hybridization can potentially lead to recombination of diverse traits and creation of unique phenotypes, but these hybrids are often sterile as is the case with the inter-subgeneric hybrid R. ?Fragrant Affinity?. Sterility in wide hybrids can either be genic or chromosomal; the latter may be overcome by induction of polyploidy which can restore chromosome homology and fertility. Initial cytological studies of ?Fragrant Affinity? showed bridges between bivalents in metaphase I and laggard chromosomes in anaphase I. In this study we successfully developed an allotetraploid form of R. ?Fragrant Affinity? using oryzalin (4-(dipropylamino)-3, 5-dinitro-benzenesulfonamide) as a mitotic inhibitor and chromosomal doubling agent. Genome sizes (2C) were determined using flow cytometry and found to be approximately 1.6 and 3.2 pg for the diploid and allotetraploid, respectively. Pollen viability, determined by staining and germination tests, was 4% and 0%, respectively for the diploid and 68% and 45%, respectively for the allotetraploid. No seeds were produced when the diploid R. ?Fragrant Affinity? was used as a maternal parent when crossed with pollen from viable diploid and tetraploid parents. The allotetraploid produced viable seeds and seedlings when crossed with pollen from either diploid or tetraploid parents, including self pollination, demonstrating restored male and female fertility. Additional crosses were successfully completed using the allotetraploid as part of an ongoing breeding program to develop new fragrant, cold hardy, evergreen rhododendron. Morphological analysis has historically been used to determine parentage of unknown hybrids. This can be difficult when the purported parental taxa have very similar morphology as in the case of the three azaleodendron cultivars R. ?Fragrans?, ?Fragrans Affinity?, and ?Fragrant Affinity?. The three cultivars are purported hybrids of R. catawbiense Michx. or R. ponticum L. and R. viscosum (L.) Torr., the three cultivars are very similar morphologically as are the purported parents. In this study, morphological and AFLP analyses were conducted to determine if these are unique cultivars or clones and to elucidate the parents. The three cultivars, potential parents from subgenera Hymenanthes (Blume) K.Koch (evergreen rhododendrons) and Pentanthera (G.Don) Pojarkova (deciduous azaleas), and related taxa from each subgenus were evaluated using 31 primer combinations. Morphological comparison indicated that R. ponticum is likely the evergreen rhododendron parent of R. ?Fragrant Affinity? based on intermediate petiole and leaf blade lengths and floral characteristics. Genetic similarity calculated using Jaccard?s coefficient of similarity was highest between the hybrids and R. ponticum among the evergreen rhododendrons and R. viscosum among the deciduous azaleas, respectively. Genetic similarities among the three azaleodendrons indicated that they are unique cultivars and not synonyms, but likely share the same parental species. A dendrogram generated using the genetic similarity matrix grouped taxa into generally accepted taxonomic groups and nested R. ponticum with the hybrids suggesting it is the evergreen rhododendron parent. Additionally, a plot of the first three principle components also showed R. ponticum to be grouped more closely with the hybrids. Furthermore, there were 18 fragments unique to R. ponticum and the hybrids, however no unique bands were found for the purported deciduous azalea parent, suggesting the original parent may have been a hybrid.