Periwinkle [Catharanthus roseus (L.) G. Don.], a member of the Apocynaceae family, is endemic to Madagascar. This plant species is known for its production of terpenoid indole alkaloids that may be used to treat cardiac diseases and certain tumors in mammals (Zhou et al., 2009). Periwinkle has become pantropical by escaping from cultivation and has become naturalized in many tropical/subtropical regions (Levy, 1981). Periwinkle has been among the top ranked bedding/garden plants in the United States as a result of its tolerance to heat and drought, and air pollution (Howe and Waters, 1994; USDA, 2010).
The flower of periwinkle is morphologically close to cleistogamous (Miyajima, 2004). The stigmatic head, with sticky secretion, is normally below the anthers and takes up the shed pollen. Periwinkle is a self-compatible plant species. However, the receptive portion is mainly on the base of the stigmatic head and thus automatic intraflower self-pollination does not normally occur (Kulkarni et al., 2005; Sreevalli et al., 2000). Nectar-seeking pollinators with probosces such as butterflies and hawkmoths are required for effective pollination by pressing pollen from dehisced anthers to the basal stigma (Miyajima, 2004). Automatic intraflower self-pollination, however, occurred in cultivars/strains with the continued growth of the gynoecium beyond the base of the anthers, i.e., the overlap between stigma and anthers (Kulkarni et al., 2001, 2005; Miyajima, 2004).
Flower doubleness commonly increases the number of petals at the expense of anthers or carpels and thus affects the pollination mechanism (Comba et al., 1999). A related double-flowered variety of lesser periwinkle (Vinca minor fl. pl.) was found in the wild with partial or complete transformation of stamens in the third whorl into petaloid organs (Wang et al., 2011). Flower doubling has been reported to be controlled by genes, either recessive in Nicotiana (Zainol and Stimart, 2001) or dominant in Petunia (Sink, 1973). We found a double-flowered mutant of periwinkle and released a new double-flowered cultivar through crossing between the mutant and a line derived from a commercial cultivar (Chen and Yeh, 2012). We report the morphology and inheritance of flower doubleness in Catharanthus roseus.
Comba, L., Corbet, S.A., Hunt, L. & Warren, B. 1999 Flowers, nectar, and insect visits: Evaluating British plant species for pollinator-friendly gardens Ann. Bot. (Lond.) 83 369 383
Dhawan, O.P., Dubey, M.K. & Khanuja, S.P.S. 2007 Detection of a true breeding homeotic gene mutant Pps-1 with partially petaloid sepals in opium poppy (Papaver somniferum L.) and its genetic behavior J. Hered. 98 373 377
Ecker, R., Barzilay, A. & Osherenko, E. 1994 Linkage relationships of genes for leaf morphology and double flowering in Matthiola incana Euphytica 74 133 136
Kulkarni, R.N., Sreevalli, Y. & Baskaran, K. 2005 Allelic differences at two loci govern different mechanisms of intraflower self-pollination in self-pollinating strains of periwinkle J. Hered. 96 71 77
Kulkarni, R.N., Sreevalli, Y., Baskaran, K. & Kumar, S. 2001 The mechanism and inheritance of intraflower self-pollination in self-pollinating variant strain of periwinkle Plant Breed. 120 247 250
Levy, A. 1981 Catharanthus roseus, p. 166–168. In: Halevy, A.H. (ed.). CRC handbook of flowering. Vol. II. CRC Press, Boca Raton, FL
Sink, K.C. Jr 1973 The inheritance of apetalous flower type in Petunia hybrida Vilm. and linkage tests with the genes for flower doubleness and grandiflora characters and its use in hybrid seed production Euphytica 22 520 526
Sreevalli, Y., Baskaran, K., Kulkarni, R.N. & Kumar, S. 2000 Further evidence for the absence of automatic and intra-flower self-pollination in periwinkle Curr. Sci. 79 1648 1649
USDA 2010 Census of agriculture. National Agricultural Statistics Service
Wang, Y.Q., Melzer, R. & Theissen, G. 2011 A double-flowered variety of lesser periwinkle (Vinca minor fl. pl.) that has persisted in the wild for more than 160 years Ann. Bot. (Lond.) 107 1445 1452
Zhou, M.L., Shao, J.R. & Tang, Y.X. 2009 Production and metabolic engineering of terpenoid indole alkaloids in cell cultures of the medicinal plant Catharanthus roseus (L.) G. Don (Madagascar periwinkle) Biotechnol. Appl. Biochem. 52 313 323