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  • Author or Editor: H. Kamemoto x
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Floral characteristics, meiotic behavior, and sporad formation were compared in three Dendrobium tetraploids (amphidiploids) and their diploid counterparts. Amphidiploid flowers were larger than those of diploids. Diploid meiotic behavior varied; mean configurations at Metaphase I ranged from 14.3 bivalents and 9.4 univalents to 18.9 bivalents and 0.2 univalents. In amphidiploids, nearly all cells had 38 bivalents. Sporad formation also varied; diploids had 36% to 70% tetrads and amphidiploids had 97% to 100% tetrads. Preferential pairing and small chromosome size may promote bivalent formation in amphidiploids.

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Abstract

Anthurium scherzerianum Schott was crossed successfully to A wendlingerii Barroso. The spathe color of the hybrid is a unique grayish-orange resulting from the combination of scarlet from A. scherzerianum and purplish-brown from A. wendlingerii. Other characteristics such as the length and coil of the spadix and the length and position of the leaf blade are intermediate between the highly contrasting characteristics of the parental species. Fertility in the hybrid was excellent, indicating a relatively close taxonomic relationship of the 2 species.

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Abstract

Cymbidium mosaic virus (CyMV) is a serious disease of Dendrobium orchids in Hawaii. Symptoms of the disease include foliar pitting or streaking and floral necrosis. Some plants do not express floral necrosis even though they are infected with the virus. These necrosis-free plants were defined as resistant for this study. Crosses were made between resistant and susceptible plants, and seedlings were inoculated with the virus. Susceptible × susceptible crosses produced susceptible offspring, resistant × resistant crosses produced resistant offspring, and susceptible × resistant crosses produced susceptible offspring, with the exception of one cross that segregated for susceptible and resistant. Expression of floral necrosis is genetically controlled and expression of necrosis is dominant to nonexpression.

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A peloric form of the labellum or lip of Dendrobium appeared in a hybrid registered by D'Bush Nursery of Australia as Dendrobium D'Bush Pansy in 1988. Unlike the typical lip of Dendrobium, the lip of D'Bush Pansy is similar to the two lateral sepals, and the flat petals and sepals resemble those of the pansy, hence the name D'Bush Pansy. A few seedlings of D'Bush Pansy were obtained from Australia through Bangkok Flowers in 1989. D'Bush Pansy crossed to several Dendrobium plants with normal lip produced offspring with normal lip, indicating that pansy-lip is recessive to normal-lip. Three F1 offspring backcrossed to the pansy-lip parent produced 1:1 ratios, and one F2 progeny segregated into 3 normal-lip: 1 pansy-lip. Thus, pansylip is controlled by a single recessive gene pair.

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Abstract

Progenies of 4 sets of reciprocal crosses in Dendrobium were compared including an intraspecific cross, 2 interspecific crosses, and an amphidiploid cross. With the reciprocal crosses involving 2 accessions of D. canaliculatum (D173-2 and D129), offspring with cytoplasm of D173-2 (Papua, New Guinea accession) were taller, produced more pseudobulbs, and gave a higher flower yield than with D129. Offspring with the same D. canaliculatum cytoplasm also produced taller plants and more pseudobulbs in reciprocal crosses between D. canaliculatum and D. strebloceras. Reciprocal crosses of D. schulleri × D. × Sunset differed in chromosome number and flower quality. D. schulleri × D. × Sunset produced triploid offspring, while the reciprocal produced diploid offspring. Reciprocal matings of 2 amphidiploid D. × Jaquelyn Thomas selections did not differ in height, yield, number of pseudobulbs, or floral characteristics.

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Abstract

A total of 1592 cross- and self-pollinations were made among 56 species of Anthurium Schott. These pollinations included 20 different seifs, 19 different intraspecific cross-combinations, 315 different intragroup interspecific cross-combinations (including reciprocals), and 29 different intergroup cross-combinations (including reciprocals); 280 fruiting spadices yielded 181 seedling populations which flowered and were evaluated both morphologically and chromosomally. Six morphological groups were constructed using primarily the characters considered as important by Engler (1905). Generally the integrity of these 6 groups was confirmed with the possible exception of Groups V and VI. Groups V and VI were more closely related to each other than to any other group, and the characters used in the division of these 2 groups were not as distinctive as those used to divide the other groups. Crossabilities in Anthurium tend to follow morphological similarities in the crosses that were attempted.

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Inbred progenies originating from the amphidiploid Dendrobium × Jaquelyn Thomas ‘Y166-1’ were produced through sellings, sibmatings, and backcrosses. An outcross was also included. Selection and inbreeding were effective in increasing flower size and improving color purity. The characters of flower size, flower color, scape length, total initiated flowers, vase life, and bud drop were primarily influenced by parental genotypes since inbreeding decline was not apparent. Continued inbreeding of individuals selected for larger, whiter flowers led to decreased numbers of racemes and shorter plants.

Open Access

Abstract

The breeding behavior of polyploid Dendrobium orchids (N=19) was investigated by making crosses involving diploids, triploids and tetraploids. Seedlings were obtained from various combinations, although the percentages of viable seed was low for crosses involving triploids. 2N × 2N crosses produced 2N offspring, 4N × 4N crosses produced 4N offspring and 2N × 4N and 4N × 2N crosses produced 3N offspring. 2N × 3N and 3N × 2N crosses gave rise to predominantly 4N progenies and small percentages of aneuploids between the 2N and 3N levels. The increase in ploidy can be attributed to the functioning of unreduced 3N gametes from the 3N parent and the normally reduced N gametes from the 2N parent. 3N × 4N and 4N × 3N crosses produced variable progenies of 5N and aneuploid offspring between the 3N and 4N levels.

Open Access

Abstract

Meiotic behavior was examined in 33 interspecific hybrids derived from 6 sections of the genus Dendrobium Swartz. The mean number of bivalents per pollen mother cell (PMC) of intrasectional Ceratobium hybrids was 18.9 as compared to 17.5 for Phalaenanthe × Ceratobium offspring. Mean bivalents of the intersectional hybrids of Ceratobium × Eleutheroglossum, Latourea × Ceratobium, Latourea × Phalaenanthe, Phalaenanthe × Eleutheroglossum, Phalaenanthe × Eugenanthe, and Phalaenanthe × Nigrohirsutae were 14.5, 9.0, 9.6, 11.8, 6.0, and 6.4, respectively. Percent of microspore tetrads formed reflected the chromosome homology of the parental species. Cytological observations indicated that species of the Ceratobium and Phalaenanthe sections are closely related, Eleutheroglossum is more closely related to Ceratobium than Phalaenanthe, and Latourea is equally related to Ceratobium and Phalaenanthe.

Open Access

Abstract

Two anthocyanins from Anthurium amnicola (Dressler) were identified as cyanidin 3-rutinoside and peonidin 3-rutinoside. HPLC chromatograms from spathe and spadix were similar. Cyanidin 3-rutinoside occurred in much larger amounts than peonidin 3-rutinoside.

Open Access