(1) Background: According to the IUCN, Boswellia pirottae is classified as a vulnerable species. However, knowledge of its seed characteristics and germination behaviour is lacking. (2) Methods: The aim of this research was to characterise the seeds and evaluate the effects of seed colour and controlled temperatures on seed germination. The seeds were segregated into the following colour categories: light brown (LB), brown (B), and dark brown (DB). The seeds were evaluated under controlled constant temperatures (23 °C) and at room (fluctuating) temperature independently. One-way ANOVA, t-test, and germination indexes were used for analyses. (3) Results: The results showed significant differences in the mean seed masses of LB, B, and DB seeds. Similarly, the differently coloured seeds varied in their water imbibition rates. The result showed significant differences in the mean germination of the seeds in both the controlled temperature (23 °C) and room-temperature chambers among the LB, B, and DB seeds. However, the t-test revealed no significant differences in the mean germination of the seeds of similar colours between controlled temperature and room temperature conditions. (4) Conclusions: The seed's colour significantly influenced the seed mass, water imbibition capacity, and germination rate relative to the temperature treatment. Dark brown seeds are recommended for seed collection aimed at seedling propagation.

Department of Forest Botany Dendrology and Geobiocoenology Faculty of Forestry and Wood Technology Mendel University in Brno Zemědělská 1 613 00 Brno Czech Republic

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Ogbazghi W., Bongers F., Rijkers T., Wessel M. Population structure and morphology of the frankincense tree Boswellia papyrifera along an altitude gradient in Eritrea. J. Drylands. 2006;1:85–94.

Lvončík S., Maděra P., Volařík D., Vrškový B., Habrová H. First proposal of seed regions for Frankincense trees (Boswellia spp.) on Socotra Island. J. Landsc. Ecol. 2013;6:36–45. doi: 10.2478/jlecol-2014-0002. DOI

Maděra P., Paschová Z., Ansorgová A., Vrškový B., Lvončík S., Habrová H. Volatile compounds in oleo-gum resin of Socotran species of Burseraceae. Acta Univ. Agric. Silvic. Mendelianae Brun. 2017;65:73–90. doi: 10.11118/actaun201765010073. DOI

Bongers F., Groenendijk P., Bekele T., Birhane E., Damtew A., Decuyper M., Zuidema P.A. Frankincense in peril. Nat. Sustain. 2019;2:602–610. doi: 10.1038/s41893-019-0322-2. DOI

Soumya K.V., Shackleton C.M., Setty S.R. Impacts of gum-resin harvest and Lantana camara invasion on the population structure and dynamics of Boswellia serrata in the Western Ghats, India. For. Ecol. Manag. 2019;453:117618. doi: 10.1016/j.foreco.2019.117618. DOI

Hamdiah S., Eler K., Van Damme K., Attorre F., La Montagna D., De Sanctis M., Shaneyehen M., Amar M., Marfo T.D., Madera P. Overgrazing strongly impedes the natural regeneration of the endemic Boswellia species on Socotra Island. J. For. Sci. 2024;70:249–263. doi: 10.17221/3/2024-JFS. DOI

Maděra P., Vahalík P., Hamdiah S., Hušková K., Sekava J., Attorre F., La Montagna D., De Sanctis M., Netek R., Bongers F., et al. Distribution, ecology, and threats assessment of 11 endemic frankincense tree taxa (Boswellia) in the Socotra Archipelago (Yemen) Plants People Planet. 2024;6:1552–1571. doi: 10.1002/ppp3.10563. DOI

Rijkers T., Ogbazghi W., Wessel M., Bongers F. The effect of tapping for frankincense on sexual reproduction in Boswellia papyrifera. J. Appl. Ecol. 2006;43:1188–1195. doi: 10.1111/j.1365-2664.2006.01215.x. DOI

Hamdiah S., Karas L., Houšková K., Van Damme K., Attorre F., Vahalík P., Habrová H., Lvončík S., Eler K., Maděra P. Seed viability and potential germination rate of nine endemic Boswellia taxa (Burseraceae) from Socotra Island (Yemen) Plants. 2022;11:1418. doi: 10.3390/plants11111418. PubMed DOI PMC

Karas L., Houšková K., Habrová H. Germination parameters of Boswellia sacra Flueck. Seeds and the possibility of their improvement by sorting. J. Appl. Res. Med. Aromat. Plants. 2023;37:100513. doi: 10.1016/j.jarmap.2023.100513. DOI

Eslamieh J. Cultivation of Boswellia: Sacred Trees of Frankincense; a Book on the History, Cultivation, Original Descriptions, Staging, Hybridization, Holistic Use, and Future of Boswellias in Our World. A Book’s Mind; Phoenix, AZ, USA: 2011. 196p

Bonfil-Sanders C., Cajero-Lázaro I., Evans R.Y. Seed germination of six Bursera species from central Mexico. Agrociencia. 2008;42:827–834.

Vásquez-García I., Mohedano-Caballero L., Cetina-Alcalá V.M. Germination of Bursera bipinnata (DC.) Engl and Bursera glabrifolia (HBK) Engl under pre-germinative treatments. Int. Res. J. Environ. Sci. 2017;6:13–17.

Choudhary M., Bano S., Tomar U.K. Biannual seed yield, viability and Germination in Commiphora wightii (Arnott) Bhandari. Biol. Life Sci. Forum. 2020;4:35. doi: 10.3390/IECPS2020-08889. DOI

Hasnat G.N.T., Hossain M.A., Hossain M.K. Pre-Sowing Treatments Accelerate Germination Percent for Restoration of Fourteen Threatened Tree Species in Bangladesh. J. Trop. For. Environ. 2019;9:36–46. doi: 10.31357/jtfe.v9i2.4466. DOI

Bewley J.D., Bradford K., Hilhorst H., Nonogaki H. Seeds—Physiology of Development, Germination and Dormancy. Springer; New York, NY, USA: 2013. DOI

Taylorson R.B. Environmental and chemical manipulation of weed seed dormancy. Weed Sci. 1987;3:135–154.

Chachalis D., Reddy K.N. Factors affecting Campsis radicans seed germination and seedling emergence. Weed Sci. 2000;48:212–216. doi: 10.1614/0043-1745(2000)048[0212:FACRSG]2.0.CO;2. DOI

Khaeim H., Kende Z., Jolánkai M., Kovács G.P., Gyuricza C., Tarnawa Á. Impact of temperature and water on seed germination and seedling growth of Maize (Zea mays L.) Agronomy. 2022;12:397. doi: 10.3390/agronomy12020397. DOI

Seo M., Nambara E., Yamaguchi S. Interaction of light and hormone signals in germinating seeds. Plant Mol. Biol. 2009;69:463–472. doi: 10.1007/s11103-008-9429-y. PubMed DOI

Amri E. Germination of Terminalia sericea Buch ex Dc. seeds: Effects of temperature regime, photoperiod, gibberellic acid and potassium nitrate. Am.-Eurasian J. Agric. Environ. Sci. 2010;8:722–727.

Shoemaker C., Carlson W.H. pH affects seed germination of eight bedding plant species. Hortic. Sci. 1990;25:762–764. doi: 10.21273/HORTSCI.25.7.762. DOI

Laghmouchi Y., Belmehdi O., Bouyahya A., Senhaji N.S., Abrini J. Effect of temperature, salt stress and pH on seed germination of medicinal plant Origanum compactum. Biocatal. Agric. Biotechnol. 2017;10:156–160. doi: 10.1016/j.bcab.2017.03.002. DOI

Koger C.H., Reddy K.N., Poston D.H. Factors affecting seed germination, seedling emergence, and survival of Texasweed (Caperonia palustris) Weed Sci. 2004;52:989–995. doi: 10.1614/WS-03-139R2. DOI

Oliveira A.K.M., Ribeiro J.W.F., Pereira K.C.L., Silva C.A.A. Germinação de sementes de Aspidosperma tomentosum Mart. (Apocynaceae) em diferentes temperaturas. Rev. Bras. Biociênc. 2011;9:392

Sghaier H.A., Tarnawa Á., Khaeim H., Kovács G.P., Gyuricza C., Kende Z. The effects of temperature and water on the seed germination and seedling development of Rapeseed (Brassica napus L.) Plants. 2022;11:2819. doi: 10.3390/plants11212819. PubMed DOI PMC

Wu H., Wang S., Wei X., Jiang M. Sensitivity of seed germination to temperature of a relict tree species from different origins along latitudinal and altitudinal gradients: Implications for response to climate change. Trees Struct. Funct. 2019;33:1435–1445. doi: 10.1007/s00468-019-01871-0. DOI

Yi F., Wang Z., Baskin C.C., Ye R., Sun H., Zhang Y., Ye X., Liu G., Yang X., Huang Z. Seed germination responses to seasonal temperature and drought stress are species-specific but not related to seed size in a desert steppe: Implications for effect of climate change on community structure. Ecol. Evol. 2019;9:2149–2159. doi: 10.1002/ece3.4909. PubMed DOI PMC

Simão E., Takaki M. Effect of light and temperature on seed germination in Tibouchina mutabilis (Vell.) Cogn. (Melastomataceae) Biota Neotrop. 2008;8:63–68. doi: 10.1590/S1676-06032008000200006. DOI

Bauerová L., Munie S.A., Houšková K., Habrová H. Germination of Dracaena cinnabari Balf.f. Seeds under Controlled Temperature Conditions. Forests. 2020;11:521. doi: 10.3390/f11050521. DOI

Szczerba A., Płażek A., Pastuszak J., Kopeć P., Hornyák M., Dubert F. Effect of low temperature on germination, growth, and seed yield of four Soybean (Glycine max L.) Cultivars. Agronomy. 2021;11:800. doi: 10.3390/agronomy11040800. DOI

Copeland L.O., McDonald M.B. Principles of Seed Science and Technology. Springer; New York, NY, USA: 2001. 467p. DOI

Watt M.S., Bloomberg M. Key features of the seed germination response to high temperatures. New Phytol. 2012;196:332–336. doi: 10.1111/j.1469-8137.2012.04280.x. PubMed DOI

Oliveira A.K.M., Ribeiro J.W.F., Pereira K.C.L., Silva C.A.A. Temperaturas para a germinação de sementes de Tabebuia ochracea (Cham.) Standl. Comunicata Sci. 2012;3:98–103.

Oliveira A.K.M., Ribeiro J.W.F., Pereira K.C.L., Silva C.A.A. Effects of temperature on the germination of Diptychandra aurantiaca (Fabaceae) seeds. Acta Sci. Agron. 2013;35:203–208. doi: 10.4025/actasciagron.v35i2.15977. DOI

Zamith L.R., Cruz D.D., Richers B.T. The effect of temperature on the germination of Melocactus violaceus Pfeiff. (Cactaceae), a threatened species in restinga sandy coastal plain of Brazil. An. Acad. Bras. Ciênc. 2013;85:615–622. doi: 10.1590/S0001-37652013000200010. PubMed DOI

Medina C.V., Rodriguez E., Bagantim A., Andrade R. Temperatura e armazenamento na germinação de sementes de Mabolo (Diospyros blancoi Willd) Nucleus. 2016;13:189–198. doi: 10.3738/1982.2278.1538. DOI

Brändel M. Effect of temperatures on dormancy and germination in three species in the Lamiaceae Occurring in Northern Wetlands. Wetl. Ecol. Manag. 2006;1:11–28. doi: 10.1007/s11273-005-1548-5. DOI

Sampayo-Maldonado S., Ordoñez-Salanueva C.A., Mattana E., Way M., Castillo-Lorenzo E., Dávila-Aranda P.D., Ulian T. Thermal niche for seed germination and species distribution model of Swietenia macrophylla King (Mahogany) under climate change scenarios. Plants. 2021;10:2377. doi: 10.3390/plants10112377. PubMed DOI PMC

Sivaramakrishnan S., Patell V.Z., Soman P. Heat shock proteins of sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.) R. Br.) cultivars with differing heat tolerance at seedling establishment stage. J. Exp. Bot. 1990;41:249–254. doi: 10.1093/jxb/41.2.249. DOI

Baskin C.C., Baskin J.M. Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination. 1st ed. Academic Press; San Diego, CA, USA: 1998. DOI

Matilla A., Gallardo M., Puga-Hermida M. Structural, physiological, and molecular aspects of heterogeneity in seeds: A review. Seed Sci. Res. 2005;15:63–76. doi: 10.1079/SSR2005203. DOI

Elias S.G., Copeland L.O. Physiological and harvest maturity of Canola in relation to seed quality. Agron. J. 2001;93:1054–1058. doi: 10.2134/agronj2001.9351054x. DOI

Atis I., Atak M., Can E., Mavi K. Seed coat color effects on seed quality and salt tolerance of red clover (Trifolium pratense) Int. J. Agric. Biol. 2011;13:363–368.

Mukassabi T.A., Polwart A., Coleshaw T., Thomas P.A. Does Scots pine seed colour affect its germination? Seed Sci. Technol. 2012;40:155–162. doi: 10.15258/sst.2012.40.2.01. DOI

Powell A.A., Oliveira M.A., Matthews S. The role of imbibition damage in determining the vigor of white and colored seed lots of dwarf French beans (Phaseolus vulgaris) J. Exp. Bot. 1986;37:716–722. doi: 10.1093/jxb/37.5.716. DOI

Powell A.A. The importance of genetically determined seed coat characteristics to seed quality in grain legumes. Ann. Bot. 1989;63:169–195. doi: 10.1093/oxfordjournals.aob.a087720. DOI

Liu W., Peffley E.B., Powell R.J., Auld D.L., Hou A. Association of seed coat color with seed water uptake, germination, and seed components in guar (Cyamopsis tetragonoloba (L.) Taub) J. Arid Environ. 2007;70:29–38. doi: 10.1016/j.jaridenv.2006.12.011. DOI

Mavi K. The relationship between seed coat color and seed quality in watermelon Crimson sweet. Hortic. Sci. 2010;37:62–69. doi: 10.17221/53/2009-HORTSCI. DOI

El-Keblawy A., Bhatt A., Gairola S. Perianth color affects germination behavior in the wind-pollinated Salsola rubescens in the Arabian Deserts. Botany. 2013;92:69–75. doi: 10.1139/cjb-2013-0183. DOI

Wang Y., Xiao L., Guo S., An F., Du D. Fine mapping and whole-genome resequencing identify the seed coat color gene in Brassica rapa. PLoS ONE. 2016;11:e0166464. doi: 10.1371/journal.pone.0166464. PubMed DOI PMC

Choudhary M., Tomar U.K. Seed parameters study in Commiphora wightii (Arnott)—An important medicinal tree of arid and semi-arid regions of India; Proceedings of the 1st International Electronic Conference on Forest—Forests for a Better Future: Sustainability, Innovation, Interdisciplinarity; Online. 15–30 November 2020; Basel, Switzerland: MDPI; DOI

Gairola S., Shabana H.A., Mahmoud T., Santo A. Effects of seed color heterogeneity on germination behavior of the desert plant Lotononis platycarpa (Fabaceae) Nord. J. Bot. 2018;36:e01617. doi: 10.1111/njb.01617. DOI

Thulin M. The Genus Boswellia (Burseraceae): The Frankincense Trees. Acta Universitatis Upsaliensis; Uppsala, Sweden: 2020.

Awas T., Belay B., Demissew S., Nemomissa S., Mekbib E., Atnafu H., Alemu S., Alemu S. Boswellia pirottae. The IUCN Red List of Threatened Species 2021: E.T34394A223071850. DOI

Vivero J.L., Kelbessa E., Demissew S. The Red List of Endemic Trees and Shrubs of Ethiopia and Eritrea. Flora and Fauna International; Cambridge, UK: 2005.

Miller A.G., Morris M. Ethnoflora of the Soqotra Archipelago. Royal Botanic Garden; Edinburgh, UK: 2004.

Tadesse W., Dejene T., Zeleke G., Desalegn G. Underutilized natural gum and resin resources in Ethiopia for future directions and commercial utilization. World J. Agric. Sci. 2020;8:32–38.

Volis S., Bohrer G. Joint evolution of seed traits along an aridity gradient: Seed size and dormancy are not two substitutable evolutionary traits in a temporally heterogeneous environment. New Phytol. 2013;197:655–667. doi: 10.1111/nph.12024. PubMed DOI

Atak M., Kaya M.D., Kaya G., Khawar K.M. Dark green colored seeds increase the seed vigor and germination ability in dry green pea (Pisum sativum L.) Pak. J. Bot. 2008;40:2345–2354.

Cruz-García S., Aguirre-Medina J.F., Espinosa-Zaragoza S., Reyes-Reyes J., Avendaño-Arrazate C.H., Guzmán-Alfonzo Y., Aguirre-Cadena J.F. Morphometric characteristics and seed germination of Dalbergia granadillo Pittier. Agro Prod. 2021 doi: 10.32854/agrop.v14i11.2156. DOI

Bhatt A., Gairola S., El-Keblawy A.A. Seed color affects light and temperature requirements during germination in two Lotus species (Fabaceae) of the Arabian subtropical deserts. Rev. Biol. Trop. 2016;64:483–692. doi: 10.15517/rbt.v64i2.18575. PubMed DOI

El-Keblawy A., Lovett-Doust J. Persistent, non-seed size maternal effects on the life history traits in the progeny generation in squash, Cucurbita pepo (Cucurbitaceae) New Phytol. 1998;140:655–666. doi: 10.1046/j.1469-8137.1998.00305.x. PubMed DOI

Zhao M., Liu Z., Zhang H., Wang Y., Yan H. Germination characteristics are more associated with phylogeny-related traits of species in salinized grassland of Northeastern China. Front. Ecol. Evol. 2021;9:748038. doi: 10.3389/fevo.2021.748038. DOI

Naylor R.E.L. WEEDS | Weed Seed Biology. In: Thomas B., editor. Encyclopedia of Applied Plant Sciences. Elsevier; Amsterdam, The Netherlands: 2003. pp. 1500–1508. DOI

Vidak M., Lazarević B., Javornik T., Šatović Z., Carović-Stanko K. Seed water absorption, germination, emergence, and seedling phenotypic characterization of the common bean landraces differing in seed size and color. Seeds. 2022;1:324–339. doi: 10.3390/seeds1040027. DOI

Xing J., Cai M., Chen S., Chen L., Lan H. Seed germination, plant growth and physiological responses of Salsola ikonnikovii to short-term NaCl stress. Plant Biosyst. 2013;147:285–297. doi: 10.1080/11263504.2012.731017. DOI

Li Z., Lu W., Yang L., Kong X., Deng X. Seed weight and germination behavior of the submerged plant Potamogeton pectinatus in the arid zone of northwest China. Ecol. Evol. 2015;5:1504–1512. doi: 10.1002/ece3.1451. PubMed DOI PMC

Eshete A., Teketay D., Lemenih M., Bongers F. Effects of resin tapping and tree size on the purity, germination, and storage behavior of Boswellia papyrifera (Del.) Hochst. Seeds from Metema District, northwestern Ethiopia. For. Ecol. Manag. 2012;269:31–36. doi: 10.1016/j.foreco.2011.12.049. DOI

Khan M.L., Bhuyan P., Singh N.D., Todaria N.P. Fruit set, seed germination, and seedling growth of Mesua ferrea Linn. (Clusiaceae) in relation to light intensity. J. Trop. For. Sci. 2002;14:35–48.

Upadhaya K., Pandey H.N., Law P.S. The effect of seed mass on germination, seedling survival, and growth in Prunus jenkinsii Hook.f. Thoms. Turk. J. Bot. 2007;31:31–36. doi: 10.13140/2.1.4078.4004. DOI

Barik S.K., Tripathi R.S., Pandey H.N., Rao P. Tree regeneration in a subtropical humid forest: Effect of cultural disturbance on seed production, dispersal and germination. J. Appl. Ecol. 1996;33:1551–1560. doi: 10.2307/2404793. DOI

Khan M.L., Bhuyan P., Shankar U., Todaria N.P. Seed germination and seedling fitness in Mesua ferrea L. in relation to fruit size and seed number per fruit. Acta Oecol. 1999;20:599–606. doi: 10.1016/S1146-609X(99)00101-0. DOI

Perez-Garcia F., Iriondo J.M., Martinez-Laborde J.B. Germination behavior in seeds of Diplotaxis erucoides and D. virgata. Weed Res. 1995;35:495–502. doi: 10.1111/j.1365-3180.1995.tb01647.x. DOI

International Seed Testing Association (ISTA) International Rules for Seed Testing. Volume 5. International Seed Testing Association; Bassersdorf, Switzerland: 2020. pp. 21–52.

FAO (Food and Agriculture Organization of the United Nations) A Guide to Forest Seed Handling. FAO; Rome, Italy: 1985. FAO Forestry Paper No. 23.

Scott S., Jones R., Williams W. Review of data analysis methods for seed germination. Crop Sci. 1984;24:1192–1199. doi: 10.2135/cropsci1984.0011183X002400060043x. DOI

Orchard T. Estimating the parameters of plant seedling emergence. Seed Sci. Technol. 1977;5:61–69.

Bench A.R., Fenner M., Edwards P. Changes in germinability, ABA content and ABA embryonic sensitivity in developing seeds of Sorghum bicolor (L.) Moench induced by water stress during grain filling. New Phytol. 1991;118:339–347. doi: 10.1111/j.1469-8137.1991.tb00986.x. PubMed DOI

Czabator F.J. Germination value: An index combining speed and completeness of pine seed germination. For. Sci. 1962;8:386–396.