Developmental mutants of Phaseolus vulgaris L.

Hybrids with abnormal development were obtained when particular genotypes of Phaseolus vulgaris L. were crossed. The phenotypic aberrations of the F₁s included retarded growth, chlorosis of the trifoliate leaves and the formation of adventitious roots on the hypocotyls. The expression of the abnormalities was dependent on the temperature. At high temperature regime (30°C/25°C, day/night), the onset of the abnormal phenotypes occurred at an early stage of development (two weeks after planting) and essentially no new growth was observed between the second and the sixth week. However, at lower temperature regimes (25°C/20°C and 20°C/15°C, day/night), the F₁s exhibited normal and vigorous growth. The abnormalities observed on F₁s at high temperature is referred to as the "crippled" phenotypes. Genetic analysis indicated that the abnormal development is conditioned by two loci, DL₁ and DL₂ (for dosage-dependent lethal). The severity and the expression of the mutant phenotypes are dependent on the allelic dosage as well as the temperature. F₁s are heterozygous for DL₁ and DL₂. Plants homozygous dominant for both loci (four dominant alleles) are classified as lethals and perish soon after germination. Plants homozygous for one of the locus but heterozygous for the other locus (three dominant alleles) are classified as sub-lethals which also perish but at a slower rate than the lethals. The expression of the lethal and the sub-lethal phenotypes is not influenced by the temperature. The developmental controls of DL₁ and DL₂ were examined through grafting experiments and hydroponic studies. Phenotypes of mutant classes were duplicated by unions of scions and stocks derived from different genotypes. These results indicate that DL₁ and DL₂ regulate a root and shoot factor respectively which contribute to the mutant phenotypes. The allelic dosage of DL₁ in the root and DL₂ in the shoot rather than the genotype of the whole plant determine the severity of the abnormal development. Plants heterozygous for both loci with a temperature-dependent expression of the mutant phenotype were used to determine physiological components involved. One of the primary morphogenetic events associated with mutant expression is the restricted root growth at high temperature which can be alleviated by the addition of cytokinin in hydroponic solution. The differential expression of DL₁ and DL₂ in the root and the shoot systems and the effect of cytokinin in restoring normal growth of heterozygotes suggest that the two loci may be related to the regulation of hormonal biosynthesis or metabolism

臺灣百合Liliun formosanurn Wall.與L. longfilorurn Thunb.之變異與特性

在百合品種Liflam formosnum及L. longifiorum中分佈於廣泛地理環境中，有不同的生長習性與植物形態，正因如此提供了篩選商業品種特性的機會。 L. formosonum 百合之高度變異性饒為有趣，特別在開花及植株高度。開拍待間關係到海拔高度，海平面地區在5月~6月開花，愈高海拔則開花較晚，在海找2000m 地區在8 一9 月開花。假若給予塭度及長日處理，開花日期可以提早至3~4月。L. longiflorum之植株高度遠較L. formosanurn為矮，後者之族群由35 公分至2 公尺高。植株的高度與遺傳及所在地點及植株年齡有關 在品種族群中，顯示高度的自交稔性，只有在L. longiflorum有25~55%之稔性。一般而可言，L. formosanurn品種之種翼較L. longiflorum為大，種子之形態與厚度可用來區別前者及後者。種子發芽而言，兩品種均對高塭敏感。兩者之開花期不同。 長日處理不能促進莖梢之萌發，但可使莖部葉片展開節間增長，促進開花。在低溫刺激和日長效應，L. formosanurn品種之球莖與實生苗的感應是相同的。 從L. formosanurn品種百合基於下列優勢可發展商業品種(1)因自交和合性可演化成可種族群(2)以純種子繁殖可以促進開花習性(3)經由種子生產商業經營可以免除病毒傳播之困擾(4)經由種間雜交可發展成”idiotype”品種

A New Variety of Musa itinerans (Musaceae) in Taiwan

Musa itinerans Cheesman var. formosana (Warb.) Hakkinen & C. L. Yeh is one of the three wild bananas in Taiwan and represents the taxon previously recognized as M. formosana (Warb. ex Schum.) Hayata [equivalent to M. basjoo Siebold & Zucc. ex linuma var.formosana (Warb. ex Schum.) S. S. Ying]. The gross morphology of M. itinerans var. formosana is stable. Some populations without variegation on the pericarps and the bracts of male buds were mainly found in a restricted area of northeast Taiwan. The morphological characteristics of the nonvariegated populations are otherwise similar to those of M. itinerans var. formosana. Their principal distinction is based on the absence of the purplish red streaking on both the pericarps and the male, fertile bracts. This character of nonvariegation is stable across the taxon's habitat and as cultivated through a 9-year period of observation. From molecular evidence, the DNA sequence for the ITS region of ribosomal DNA (rDNA) is highly similar in both populations. The nonvariegated population is herein segregated as the new variety, M. itinerans var. kavalanensis H. L. Chin, C. T. Shii & T. Y. A. Yang. Photos for the three varietal taxa, M. itinerans var. chinensis, variety formosana, and variety kavalanensis, and a key to Taiwanese wild bananas are also provided

Musa itinerans var. chiumei (Musaceae), A New Addition to the Taiwan Flora

Another new variety of Musa itinerans Cheesman in Taiwan is described. The morphological characteristics of the variety are otherwise similar to those of var. formosana (Warb. ex Schum.) Halddnen & C.-L.Yeh. The principal distinction is based on the length and bending of inflorescence, and the compactness of fruit hands. The inflorescence rachis of the new variety is longer than the other two varieties, and first upwardly slanting, then curving downwards, finally pendent in the male flower regions. The fruit hands grow very compactly and apex of fruit remains distinguished floral relicts. These characteristics are stable at their habitat and Taiwan Agricultural Research Institute (TART) repository over study periods. This population is herein segregated as the new variety, M. itinerans var. chiumei H.-L. Chiu, C.-T. Shii & T.-Y.A. Yang. Photos for the varietal taxon as well as the key to all variation of Musa itinerans and Taiwanese wild bananas are provided

Musa × formobisiana (Musaceae), a new interspecific hybrid Banana

Taiwan is near the northern limit of distribution of Musaceae. To understand the genetics and extent of genetic diversity in wild bananas in Taiwan, artificial hybrids between Musa itinerans var. formosana and M. balbisiana Colla, here named Musa × formobisiana H.-L. Chiu, C.-T. Shii & T.-Y.A. Yang hybrid nov., were produced. Photos and a comparison of the characteristics of Musa × formobisiana with the parent species are provided. Voucher specimens are at the Herbarium, National Museum of Natural Science, Taiwan (TNM)

Musa itinerans var. chiumei (Musaceae), A New Addition to the Taiwan Flora

Another new variety of Musa itinerans Cheesman in Taiwan is described. The morphological characteristics of the variety are otherwise similar to those of var. formosana (Warb. ex Schum.) Häkkinen & C.-L.Yeh. The principal distinction is based on the length and bending of inflorescence, and the compactness of fruit hands. The inflorescence rachis of the new variety is longer than the other two varieties, and first upwardly slanting, then curving downwards, finally pendent in the male flower regions. The fruit hands grow very compactly and apex of fruit remains distinguished floral relicts. These characteristics are stable at their habitat and Taiwan Agricultural Research Institute (TARI) repository over study periods. This population is herein segregated as the new variety, M. itinerans var. chiumei H.-L. Chiu, C.-T. Shii & T.-Y.A. Yang. Photos for the varietal taxon as well as the key to all variation of Musa itinerans and Taiwanese wild bananas are provided

Musa x formobisiana (Musaceae), a new interspecific hybrid Banana

Taiwan is near the northern limit of distribution of Musaceae. To understand the genetics and extent of genetic diversity in wild bananas in Taiwan, artificial hybrids between Musa itinerans var. formosana and M. balbisiana Colla, here named Musa x formobisiana H.-L. Chiu, C.-T. Shii & T.-Y.A. Yang hybrid nov., were produced. Photos and a comparison of the characteristics of Musa x formobisiana with the parent species are provided. Voucher specimens are at the Herbarium, National Museum of Natural Science, Taiwan (TNM)

Origin of Cultivated Bananas

香蕉作物栽培種的原種主要是Musa acuminata 與M. balbisiana，此外在一些栽培種的遺傳組成中亦可找到 M. schizocarpa 與M. texitile的基因組。從野生種演化為栽培種的關鍵為果實單為結果與植株雌不稔。至少三個顯性因子控制單為結果，且具此特性的品種均帶有 M. acuminata ssp. banksii 或 M. acuminata ssp. errans 的基因組。相伴隨的雌不稔性則可能為遺傳控制或染色體異常與受環境影響而引起，絕對的雌不稔保證了栽培種之可食性，而部分的雌不稔則為栽培種的雜種化與多倍體化開啟一扇大門。2n配子的產生使得香蕉作物可以經由單向有性雜交的方式而三倍體化，在高溫、高光照與低濕的環境下較易產生2n雌配子，且主要是因發生了第二次減數分裂回復(second division restitution, SDR)而產生的；2n雄配子則僅在栽培種觀察到，且至少一個基因座參予其形成。菲律賓群島-印尼群島東部-巴布亞及新幾內亞等地是香蕉作物最初栽培化的地區，最初的三倍體尖蕉在印尼群島東部以外之島嶼東南亞與大陸東南亞等地產生，而三倍體菜蕉則可能在印尼群島東部。 Most banana cultivars are derived from two species, Musa acuminata (A genome) and M. balbisiana (B genome), however M. schizocarpa (S genome) and M. textiles (T genome) also been found in the genetic constitute of several landraces. Edibility of mature fruits came out as a result of parthenocarpy and female sterility. Parethnocarpy was controlled by at least three dominant genes, and showed to be linked to M. acuminata ssp. banksii and/or M. acuminata ssp. errans. Female sterility may be controlled by genetic or caused by chromosome abnormality or by environment. Absolute female sterility proved to be essential for the edibility of cultivars, however partial female sterility offered the opportunity of hybridity and polyploidization. The presence of 2n gametes in diploid species suggests that unilateral sexual polyploidization (2n x n) could have been involved in the origin of triploid Musa species. The generation of 2n eggs probably came out as a result of second division restitution (SDR). Relatively high production of 2n eggs was under high temperature, high solar radiation and low relatively humidity conditions. 2n pollens were observed only in cultivated genotypes and was controlled by at least one locus. M. acuminata ssp. banksii became domesticated first in the Philippines – eastern Indonesia-New Guinea area and later progressively in the rest of eastern Indonesia and mainland Southeast Asia, where AAA triploids were generated. When M. balbisiana moved southward through the Philippines and the Moluccas to the eastern Indonesia, produced the first AAB hybrids