Six species of Meconopsis were investigated for self-fertility and cross compatibility in order to incorporate desirable characters from both parents. The six species used were: M. cambrica, M. villosa, M. quintuplinervia, M. betonicifolia, M. horridula, M. aculeata. Chromosome counts were made: M. cambrica, n=14; M. villosa, n=16; M. quintuplinervia, n= c.42; M. betonicifolia, n=40; M. horridula, n=28 and M. aculeata, n=28. Interspecific compatibility was correlated with differences in ploidy level between parents. All crosses made except M. cambrica x quintuplinervia set seeds. M. cambrica, M. betonicif olia, M. horridula and M. aculeata are self-compatible. Pollination mechanisms and the likelihood of apogamy were investigated in M. betonicifolia. No apogamy was found and insects are the likely pollinators for this species. As some of the species do not flower at the same time, pollen staining, pollen germination and storage conditions for the six species were studied. Experimental alteration of flowering periods through controlling temperatures and day-lengths for M. betonicifolia was also carried out. This part of the project shows: (1) pollen stainability (stained by lactophenol cotton blue) for the six species was 85% or more; (2) pollen of all six species except M. quintuplinervia germinated on an agar medium containing sucrose (5 g 1⁻¹) and H₃BO₃ (0.1 mg 1⁻¹); (3) pollen germination percentage decreased with storage time in a desiccator at 4-6°C; and (4) long daylength (16 h) was suitable for growth and flowering of M. betonicifolia. High temperature (17°C) induced earlier growth and flowering than low temperature (6°C) in M. betonicifolia. Because of difficulties in vegetative reproduction and seed storage, in vitro establishment of M. betonicifolia was investigated. The unopened capsule sterilization method was used. The seeds in the capsule germinated on Murashige and Skoog medium. Derooted seedlings, hypocotyls and seedling roots from seedlings raised on sterile artificial medium were used as explants for the in vitro establishment. This experiment shows that half strength Murashige and Skoog medium is suitable for in vitro culture of this species. The cytokinin:auxin ratio and growth regulator concentration were found to control morphogenesis of M. betonicifolia in vitro. Derooted seedlings cultured first on nutrient medium containing N⁶-benzyladenine (BA) and kinetin (Kn) differentiated more multiple meristems than those originally cultured on medium containing N⁶-(2-isopentenyl)-adenine (2ip) after being transferred into medium containing 2ip. Multiple meristems were divided and proliferated on medium containing 0.2 mg 1⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D), 5 mg 1⁻¹ 2ip and 1 mg 1⁻¹ BA. Seedling roots and hypocotyls formed callus on media containing 1, 5 and 10 mg 1⁻¹ 2,4-D. / Land and Food Systems, Faculty of / Graduate

Known as the Himalayan poppies or the blue poppies, Meconopsis is a genus with approximately 50 species distributed through the high altitude of the Himalaya and the Hengduan Mountains (SW China). This dissertation is a study of the systematics of Meconopsis primarily using molecular phylogenetic methods. DNA sequences of chloroplast matK, ndhF, trnL-trnF, rbcL, and nuclear ITS were collected to reconstruct the phylogenies of the genus. Results showed that traditional Meconopsis is a polyphyletic group and revealed extensive mismatches between the nuclear ITS tree and the chloroplast tree. Based on the phylogenies, the taxonomy of Meconopsis was revised, making Meconopsis monophyletic. Four new sections (sect. Meconopsis, sect. Aculeatae, sect. Primulinae, and sect. Grandes) were proposed as well as a species complex (M. horridula). The chloroplast phylogeny and a likelihood method (chromEvol) were applied to ancestral chromosome number estimation to reconstruct the polyploidy evolution history of the genus. The analysis recovered an ancient triploid ancestor shared by sect. Primulinae and sect. Grandes. A low-copy nuclear gene (GAPDH) network of Meconopsis was further reconstructed, which indicated that the ancient triploid ancestor was formed by hybridization. A hypothesis of reticulate history of Meconopsis was also proposed based on the GAPDH network. Using a reconstructed rbcL phylogeny of Ranunculales, the stem group of Meconopsis was estimated at ca. 22 Mya by molecular dating, which coincided with the time of Asian interior desertification and the onset of Asian monsoon. These climatic changes could possibly have been the impetus for the split between Meconopsis and its sister clade. Ancestral area reconstruction was further conducted using likelihood-based methods. The result indicated that Meconopsis originated in the Himalaya, most likely in the west Himalaya, followed by migration to the Hengduan Mountains. / text