For centuries, roses have been treasured for their therapeutic, cosmetic, and ornamental qualities. Among its many qualities, flower fragrance holds significant economic value. Over 400 volatile compounds contribute to the complex aroma of roses, with terpenoids, phenylpropanoids, and benzenoids playing dominant roles. Among these, geraniol, a monoterpene, contributes notably to the signature scent of rose oil. However, the fragrance of modern roses has gradually diminished as breeders have focused on enhancing other traits like appearance, adaptation, durability, and vase life. To gain a better molecular understanding of specialized metabolic pathways related to floral scent in roses we carried out QTL studies in the SWxBE autotetraploid rose population [Rosa L. ‘ORAfantanov’ (Stormy Weather™) x Rosa L. ‘Radbrite’ (Brite Eyes™)]. Our study suggests that the QTL for the fragrance was identified on chromosome 2 which colocalized with the genes involved with fragrance such as ODO1, EOBIII, and NUDIX. Two rose genotypes from the SWxBE population, ‘16401-N055’ (slightly fragrant) and ‘16089-N051’ (highly fragrant), were used for transcriptomic analysis. Gene expression analysis suggests that the monoterpenoid pathway was highly active in the highly fragrant rose with the NUDIX gene being highly expressed. Thus, NUDIX, a gene involved in geraniol biosynthesis, is a strong candidate gene for the QTL on chromosome 2. This study lays the groundwork for further exploration of the molecular pathways responsible for the scent of roses.
The major bottleneck in anthurium cultivar release is the availability of microprogated plants for field testing. Genotype has been a major consideration for anthurium protocol development. Different genotypes vary in in vitro performance even when using optimized media, therefore assessing proliferative variation under in vitro conditions could help identify cultivars that could introgress tissue culture traits and provide guidelines for future protocol development. The objective of this study is to assess the in vitro performance of different anthurium accessions from the University of Hawaii anthurium breeding program under the RITA® temporary immersion system and to observe how lineage affects in vitro performance. To evaluate shoot initiation/proliferation, 20 accessions of anthurium (parents, interspecific hybrids, complex hybrids, and wild relatives) were placed in RITA® supplemented with a liquid medium containing 0.3X MS salts with 0.2 mg/L BA, 15% coconut water and 20 g/L sucrose. Primary shoots were excised after 45 days to allow axillary buds to develop into secondary shoots. Bud masses (trimmed explant bases) were placed on a solid medium containing ½ MS salts with 15% coconut water, 20 g/L sucrose and 2g/L gellan gum to observe shoot proliferation and growth. Parameters were analyzed using mixed models with time block as random effects and accessions as fixed effects. Previously identified check cultivars (‘Marian Seefurth’ and ‘New Pahoa Red’) were used as controls in this study. Significant differences among the genotypes were observed in terms of the number of primary shoots, the number of secondary shoots, total axillary bud mass volume (cm3), number of explants with shoot, and number of explants with roots. Three selections and an accession were identified to have potential use for breeding. UH2053, UH2409, UH2327 and ‘New Pahoa Red’ showed superior or comparable number of primary and secondary shoots, explant volume, and rooting compared to the check cultivars. These lines will be considered as parents in future crosses for cultivar development. Cluster analysis was also performed and was cross-referenced to existing pedigree and breeding records. Our analysis revealed five clusters which indicate that that parentage influenced in vitro shoot production particularly in lines with Anthurium andraeanum, A. amnicola, A. formosum and A. kamemotoanum in their background. Pedigree and breeding records are valuable resources for predicting response profiles of anthurium in vitro performance.
Anthuriums are Hawaii’s top cut flower with its sales valued at USD1.6 M in 2022. It is an important floriculture crop as it is both used as cut flower and foliage. Development of new genotypes allows the growers in Hawaii to produce new cultivars desired by the market. The University of Hawaii anthurium breeding program has identified new selections to field test with commercial growers. In order to do so, the breeding program propagates these selections to send to growers. Recently the use of bioreactors, such as RITA® on ‘New Pahoa Red’, resulted in three times more shoot production than in traditional flasks placed on a platform shaker. Shoot and root production and axillary bud mass volume of three new selections, UH2647, UH2651, and UH2652, were compared against the control ‘New Pahoa Red’. Ten nodes of each genotype were placed in a RITA® bioreactor, and replicated five times in a completely randomized design. Nodes were cultured in liquid medium consisting of 0.3MS, 0.1 mg l-1 BA, 15% coconut water, 20 g l-1 sucrose, and 1 ml l-1 NaSiO3. The plants were cultured in the bioreactors for 1.5 months, and then removed to obtain the number of shoots, roots, and axillary bud mass volume. Primary shoots were excised and transferred to 0.3 MS, 15% coconut water, 20 g l-1 sucrose, and solidified with 6 g l-1 Gelzan® to promote axillary bud growth and shoot development. The pH for all media was adjusted to 5.8. One month later, shoots (~0.5 cm in height) were excised from the axillary bud masses. Shoot counts excised after initial culture in the liquid medium and after placement in the shoot development solid medium were analyzed using one-way ANOVA on R studio. Axillary bud mass volume and root number were analyzed. UH2647 significantly produced more shoots than UH2652 and ‘New Pahoa Red’, while UH2651 was not different from any genotype. UH2647 also had the highest average axillary bud mass volume. UH2651 and UH2652 produced significantly more roots than the control. Knowing the genotypic differences in shoot production will assist propagation facilities in developing guidelines to schedule production of individual genotypes.
Salvia coccinea (diploid) and Salvia splendens (tetraploid) and their associated cultivars are widely available, commercially profitable, and environmentally supportive flowering annuals. In recent years, exciting cultivars have been successfully introduced. This investigation explores further development of S. coccinea ‘Summer Jewel Lavender’, S. coccinea ‘Hummingbird Forest Fire’, and S. splendens ‘Mojave Red and White Bicolor’ through treatments by oryzalin for the potential development of novel cultivars. Surflan™ or oryzalin (4-(dipropylamino)-3,5-dinitrobenzenesulfonamide) and the nonionic surfactant SilEnergy™ were applied as a foliar spray for one, two, three, and six days to induce changes in chromosome numbers. Data collected included morphological observations, measurements of foliage and flowers, flower numbers, and ploidy analysis via a CytoFLEX™ flow cytometer. Ploidy changes were achieved in seedlings across all the treatment groups. Novel traits were identified, ranging from smaller overall growth habits and foliage, larger and increased numbers of flowers, and new floral pigmentation while maintaining vigor and potential for container production. Optimization of treatments will be discussed. The findings of this research have practical implications for plant breeders, landscape designers and architects, horticulturists, and environmental researchers as the market continues to demand drought-tolerant, low-growing, long-flowering, and pollinator-attracting plants.
