Introgression of genes into cultivated Brassica napus through resynthesis of B. napus via ovule culture and the accompanying change in fatty acid composition

Fifteen lines of Brassica napus were resynthesized via ovule culture through 24 interspecific crosses between four Brassica oleracea and three Brassica campestris accessions. The degree of success in the interspecific crosses was significantly influenced by maternal genotypes. The interspecific hybrid production rate (HPR) varied with combinations from 0 to 76.9%, with a mean HPR of 24.7% for the crosses with B. campestris as the female parent and 6.9% for the crosses with B. oleracea as female parent. Twenty‐four crosses between seven natural and six resynthesized B. napus gave, on average, 10.3 seeds per pod, and ranged from 1.2 to 22.0 seeds per pod, depending on genotypes of both parents. Resynthesized lines of B. napus showed high erucic acid content and variable content of linolenic acid, ranging from 3.4% to 9.9%. The fatty acid composition in hybrid seeds between natural and resynthesized B. napus was dominated by the embryo genotypes; an additive mode was shown for erucic acid and positive over‐dominance for linolenic acid content.     

Cytoplasmic relatedness of apple landraces and cultivars: a molecular analysis

Summary Mitochondrial DNA (mtDNA) diversity has been determined in apple landraces and cultivars, based upon restriction fragment length polymorphisms (RFLPs) for several mitochondrial genes. Our analysis includes three cultivars, Golden Delicious, McIntosh and Delicious, which represent the various patterns of mtDNA polymorphisms previously described (Ishikawa et al., 1992). A total of five RFLPs were detected, allowing classification of the apple genotypes into four cytoplasmic groups: GroupI, Golden Delicious-type; GroupII, McIntosh-type; GroupIII, Delicious-type; and Group IV, Dolgo Crab-type. European landraces and cultivars were assigned to Groups I, II, and III, while chinese crab apples were placed in either Group III or IV.     

Effect of genome composition and cytoplasm on petal colour in resynthesized amphidiploids and sesquidiploids derived from crosses between Brassica rapa and Brassica oleracea

The effect of genome composition and cytoplasm on petal colour was studied in Brassica. Three accessions of yellow‐petalled B. rapa (2n= 20, AA) were crossed with a white‐petalled B. oleracea var. alboglabra (2n= 18, CC) and with three cream‐yellow‐petalled B. oleracea var. gongylodes (2n= 18, CC) to produce resynthesized B. napus (2n= 38, AACC or CCAA) and sesquidiploids (2n= 29, AAC or CAA). Petal colour was measured with a Hunter automatic colour difference meter. The results revealed that petal colour in Brassica is controlled by nuclear genes and by cytoplasmic factors. Additive and epistatic gene effects were involved in the action of nuclear genes. When crosses were made between yellow‐petalled B. rapa and white‐petalled B. oleracea var. alboglabra, significant additive, epistatic and cytoplasmic effects were found. White petal colour was partially epistatic over yellow petal colour. When crosses were made between yellow‐petalled B. rapa and cream‐yellow‐petalled B. oleracea var. gongylodes, only epistatic effects were detected. Yellow petal colour was epistatic over cream‐yellow.     

Simplified culture method of detached ears and its application to vernalization in wheat

Summary The effects of the addition of sulfurous acid into culture solution and of cold treatment of the solution were examined to simplify the culture of detached wheat ears. In the simplified method, detached ears could be cultured at room temperature on the liquid medium containing 100 g/l sucrose and 0.075% sulfurous acid without any sterilization. The immature seeds in detached ears cultured by this method were treated with low temperature or with chemicals known to have vernalizing effect. The chemical treatment did not affect the chilling requirement of immature embryos, although photoperiodic response and narrow-sense earliness were reduced by kinetin and trypsin. The low temperature treatment drastically affected the chilling requirement, and fully vernalized mature seeds having normal germinability were obtained by treating the detached ears in culture with low temperature from 10 days after anthesis.     

Nucleus substitution of Brassica japonica Sieb. with Raphanus sativus L. and its resultant chlorophyll deficiency

Summary Nucleus substitution of Brassica japonica (2n=20) with Raphanus sativus (2n=18) was carried out by means of repeated backcrossing of Brassicoraphavus (2n=37) to R. sativus as a pollen donor. In the course of nucleus substitution, chlorophyll deficiency appeared. Plants with more than 28 chromosomes, like their parents, had green leaves and those with 24 to 26 chromosomes had yellowish green ones. Almost all plants with 18 to 23 chromosomes showed yellow or whitish yellow. The R. sativus with B. japonica cytoplasm (2n=18) was obtained after four successive backerosses. The completely substituted R. sativus showed the same fertility as the true R. sativus used as a recurrent parent. It is assumed that the chlorophyll deficiency is caused by disharmony between the B. japonica cytoplasm and the R. sativus nucleus. The chlorophyll deficiency is discussed in comparison with male sterility or other characters which sometimes occur in alloplasmic Raphanus and Brassica species.     

Study on Mismatched Engagement of Hourglass Worm Gearing with The Worm Generated by A Cone and The Wheel Generdted by A Straight Profile Hob

A method to make the hourglass worm gearing with the property of mismatchedpoint contact has been proposed.The worm and the hob of the worm gearing is generated by a coneand a straight line located on the cone respectively. The basic principle of the worm gearing has beenanalysed. The formulas for calcultating the machining parameters has been obtained. And the toothcontact of the worm gearing has been investigated.The result shows that this worm gearing could getopint contact well.     

Mitochondrial DNA Restriction Fragment Length Polymorphisms in Malus Species

Three apple (Malus×domestica) cultivars and 11 Malus accessions have been investigated by the probe hybridization method on their mitochondrial DNA (mtDNA). The gene probes used were: coxI, coxII, atpA, atp6, and atp9. Our results revealed enough variation to characterize ten mtDNA haplotypes among the Malus genotypes examined. The taxonomic and phylogenetic implications of mtDNA polymorphism are also discussed.     

Characterization of six varieties of Cucumis melo L. based on morphological and physiological characters, including shelf-life of fruit

Seventy-two accessions covering six varieties of Cucumis melo were characterized by using 35 morphological characters with emphasis on shelf-life, and the relationships between shelf-life and related characters was investigated. Principal component analysis (PCA) revealed that development period of plant and fruit, size of seed and fruit, shelf-life, stem hair, flesh juiciness, netting, abscission of peduncle, rapid yellowing of epidermis at maturity, Brix value, and color of flesh and epidermis etc. were the principal characters to discriminate melon accessions examined in the present study. According to the scatter diagram, vars. acidulusand makuwa, both of which belong to the Oriental melon, are closely related because of their short growth duration, small seed, thin pericarp and poor shelf-life, while American cantaloupe (var.reticulatus) and European cantaloupe (var. cantalupensis) are rather closely related due to their climacteric fruit with orange flesh, slipped peduncle and rapid yellowing of epidermis at maturity, which is closely related with their shelf-life. PCA also indicated that var. saccharinus was closer to var. inodorus than to the other varieties, due to their requirement of long period for development, large size of seed and fruit, and half- or non-slipped peduncle. Shelf-life of melon fruit was significantly correlated with the following characters: quality of flesh, size of seed and fruit, abscission of peduncle, development periods of plant and fruit, rapid yellowing of epidermis at maturity, Brix value and color of flesh and epidermis. Accessions with good shelf-life were mostly found in vars. saccharinus and inodorus. This revised version was published online in July 2006 with corrections to the Cover Date.     

Species relationships in the subgenus Ceratotropis (genus Vigna) as revealed by RAPD analysis

Summary The genetic variation among 23 accessions of 5 species in the subgenus Ceratotropis, genus Vigna, were investigated by random amplified polymorphic DNA (RAPD) analysis. A total of 404 fragments amplified with 24 primers were scored and analyzed by cluster analysis. The accessions used were separated into two main groups with an average of 70% differences. Within the main groups, five subgroups were recognized, which are in complete agreement with taxonomic species. Wild forms were always grouped with their most closely related cultivated forms and they showed variation in each species. The largest intraspecific variation was found in V. radiata (mungbean), in which wild forms (V. radiata var. sublobata) were highly different from each other and from cultivated forms. V. angularis (adzuki bean) showed the least variation and thus, was probably differentiated in relatively recent times.     

Identification and characterization of foliar polyphenolic composition in sweetpotato (Ipomoea batatas L.) genotypes

Trials over two years were conducted using 1389 sweetpotato (Ipomoea batatas L.) genotypes collected from all over the world to characterize the polyphenolic composition in sweetpotato leaves. Wide variation was observed in relation to their total and individual leaf polyphenolic constituents. In all genotypes studied, the total polyphenol contents of sweetpotato leaf ranged from 1.42 to 17.1 g/100 g dry weight. The six different polyphenolic compounds were identified and quantified by NMR, FABMS, and RPHPLC analysis procedures. This is the first report of polyphenolic compositions in sweetpotato leaves. The relative levels of polyphenolic acids in sweetpotato leaves were as follows: 3,5-di-O-caffeoylquinic acid > 4,5-di-O-caffeoylquinic acid > chlorogenic acid (3-O-caffeoylquinic acid) > 3,4-di-O-caffeoylquinic acid > 3,4,5-tri-O-caffeoylquinic acid > caffeic acid. The highest 3,4,5-tri-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid occurred at 221 and 1183.30 mg/100 g dry weight, respectively.