HYBRIDS AND GENOME RELATIONS OF HIBISCUS SABDARIFFA,H. MEEUSEI,H. RADIATUS AND H. ACETOSELLA

Chromosome pairing was studied in the following hybrids: Hibiscus radiatus-meeusei (tetraploid F₁), H. sabdariffa-meeusei (tetraploid F₁ and spontaneous allooctoploid F₂), and hexaploid H. acetosella-(sabdariffa-meeusei). Genome constitutions of the species adduced from these data are symbolized as follows: H. radiatus and H. acetosella, AABB; H. meeusei, AAXX; H.sabdariffa, XXYY or AAYY.     

中国云南象牙参属(姜科)一新种——苍山象牙参

描述了中国云南姜科Zingiberaceae一新种——苍山象才参Roscoea cangshanensisM．H．LUO,X．F．Gao＆H．H．Lin。该种与大理象牙参R．forrestii Cowley在体态上相近,但唇瓣深裂成2裂片,每个裂片再2裂,基部收缩成具白色条纹的柄,叶片较狭窄,（2-）7-24×1．5-2．5cm,叶片基部狭缩成叶柄状而不同。该新种叶片基部狭缩成叶柄状,唇瓣倒卵状楔形,长2．5-3．5cm,宽2．5-3．0cm,基部收缩成具白色条纹的柄,与长柄象牙参R．debilis Gagnep．相似,但苞片非管状,较短,长5-15mm,隐藏于叶鞘内,花冠管较长,10-12.5cm,唇瓣深裂成2裂片,每个裂片再2裂,可与后者明显区别。     

Pathogenicity of Hirschmanniella oryzae,H. spinicaudata,and H. imamuri on Rice

In greenhouse experiments Hirschmanniella oryzae, H. imamuri, and H. spinicaudata depressed and delayed the tillering and flowering of rice, and suppressed root and shoot growth and grain yield.     

Phylogenetic analysis of the core histones H2A, H2B, H3, and H4.

Despite the ubiquity of histones in eukaryotes and their important role in determining the structure and function of chromatin, no detailed studies of the evolution of the histones have been reported. We have constructed phylogenetic trees for the core histones H2A, H2B, H3, and H4. Histones which form dimers (H2A/H2B and H3/H4) have very similar trees and appear to have co-evolved, with the exception of the divergent sea urchin testis H2Bs, for which no corresponding divergent H2As have been identified. The trees for H2A and H2B also support the theory that animals and fungi have a common ancestor. H3 and H4 are 10-fold less divergent than H2A and H2B. Three evolutionary histories are observed for histone variants. H2A.F/Z-type variants arose once early in evolution, while H2A.X variants arose separately, during the evolution of multicellular animals. H3.3-type variants have arisen in multiple independent events.     

Roscoea cangshanensis M. H. Luo,X. F. Gao & H. H. Lin,a new species of the Zingiberaceae from Yunnan,China

Roscoea cangshanensis M. H. Luo, X. F. Gao & H. H. Lin, a new species of the Zingiberaceae from Yunnan, China, is described and illustrated. The new species is related to R. forrestii Cowley in habit, but differs in having 2-lobed labellum, each lobe 2-lobulate, base narrowed to a stalk with white lines, and narrower leaf blade, (2–)7–24×1.5–2.5 cm, with base narrow to petiole-like. The new species is also similar to R. debilis Gagnep. in having leaf base narrow to petiole-like, labellum obovate-cuneate, 2.5–3.5×2.5–3.0 cm, with white lines at throat, but differs in having bracts non-tubular, shorter, 5–15 mm long, concealed in leaf sheaths, corolla tubes longer, 10–12.5 cm long, labellum 2-lobed with each lobe further 2-lobulate.     

CHROMOSOMES AND CROSSING BEHAVIOR OF HIBISCUS CANNABINUS,H. ACETOSELLA,AND H. RADIATUS

Menzel , Margaret Y. (Florida State U., Tallahassee), and F. D. Wilson . Chromosomes and crossing behavior of Hibiscus cannabinus, H. acetosella, and H. radiatus. Amer. Jour. Bot. 48(8): 651–657. Illus. 1961.—Chromosomes of diploid H. cannabinus L. (kenaf) form 18 bivalents at metaphase I. In autotetraploid H. cannabinus (2n = 72), more than 50% of the chromosomes pair as trivalents or quadrivalents. In the tetraploid species H. radiatus Cav. and H. acetosella Welw. ex Hiern (H. eetveldeanus De Wild. & Dur.) (2n = 72), only 4% of the chromosomes pair as multivalents and the rest pair as bivalents. Vigorous, highly fertile F₁ hybrids between H. acetosella and H. radiatus are easily obtained, show complete chromosome pairing, and give rise to a freely segregating, vigorous, fertile F₂: apparently the parental species have similar genome constitutions and are closely related. Chromosome pairing in the triploid hybrids of H. radiatus and H. acetosella with H. cannabinus, in hexaploids obtained by doubling the chromosome number of H. acetosella-cannabinus F₁, and in pentaploid and tetraploid backcrosses of the hexaploids to H. cannabinus shows that the tetraploid species each contain 1 genome (A) very similar to, but not identical with, that of H. cannabinus and 1 dissimilar genome (B). Morphology, fertility, and other characteristics of the various hybrids are discussed in connection with the problem of recombining the resistance to root-knot nematodes found in the tetraploid species with the desirable fiber properties of H. cannabinus.