Sexual hybridization between Capsella bursa‐pastoris (L.) Medik (♀) and Camelina sativa (L.) Crantz (♂) (Brassicaceae)

The development of transgenic oilseed Camelina sativa (2n = 40) and the potential for hybridization with its weedy relative Capsella bursa‐pastoris (2n = 36) necessitates a careful evaluation of the reproductive compatibility between the species. Here, we conducted over 1800 crosses (emasculation and manual pollination) to examine the ability of 10 Canadian C. bursa‐pastoris (♀) accessions to hybridize with five accessions of C. sativa (♂). Seven hybrids were confirmed among 586 putative hybrids screened with species‐specific markers, indicating a hybridization rate of 1.5 hybrids per 10 000 ovules pollinated. All seven hybrids had intermediate DNA content compared to their parents, were morphologically distinct, had low (1.9%) pollen fertility and failed to produce selfed or backcrossed seed. Given the abundance of C. bursa‐pastoris along field margins, hybrids will likely be generated in the wild, but they will be unable to establish lineages unless fertility is restored. The large number of crosses and the diversity captured by the use of multiple accessions resulted in strong statistical power and a high degree of confidence in the estimated hybridization rate.     

氮磷钾与茶叶品质关系的研究综述

茶叶是中国重要的经济作物,茶多酚、儿茶素、氨基酸、咖啡碱和水浸出物为国际上公认的茶叶品质成份。氮、磷、钾是茶树正常生长所必需的营养元素,它们与茶叶品质成分的形成与含量有着密切关系。适量的施氮对茶叶品质有较好的促进作用,施氮不足或过量则会对茶叶品质产生极大的不良影响;此外,茶树有喜铵耐铵的特性,施用NH4+—N肥有利于改善茶叶品质。磷能促进类黄酮物质的形成以及增加茶多酚、氨基酸和咖啡碱的含量。钾能显著提高茶叶中的游离氨基酸、茶多酚等内含物的含量,对水浸出物、儿茶素等含量也有影响;不同钾肥品种对茶叶品质影响不同,就提高茶叶氨基酸的效果而言,以硫酸钾最好。氮、磷、钾三种元素配合施用对提高茶叶品质起到良好的效果,单施其中一种不仅无助于茶叶品质的提高,反而会使茶叶品质降低。     

Interspecific hybridization between urdbean (Vigna mungo (L.) Hepper) and adzukibean (Vigna angularis (Willd.) Ohwi and Ohashi)

Summary To introduce resistance to fungal and viral diseases into urdbean (Vigna mungo), it was crossed with adzukibean (Vigna angularis) to achieve an interspecific hybrid between the two species by using different non-conventional breeding methods. Partial success was obtained with the use of UV irradiated pollen, intraspecific hybrids as parents and spray of immuno-suppressants on the female parent under glass house conditions and to the extent of callusing in aseptic culture.     

异色瓢虫对菜缢管蚜、禾谷缢管蚜和白杨毛蚜捕食的作用

异色瓢虫是一种重要的捕食性天敌,可捕食多种蚜虫,在生物防治中具有很大应用前景。研究了异色瓢虫对3种蚜虫(即菜缢管蚜、禾谷缢管蚜和白杨毛蚜)的捕食功能反应。结果表明：异色瓢虫对3种蚜虫的日捕食量中,其中四龄幼虫最大,成虫和三龄幼虫次之,1、2龄幼虫最小。捕食者对猎物的功能反应均属于Holling-Ⅱ型方程。     

Synthesis of somatic hybrids (RCBB) by fusing heat-tolerant Raphanus sativus (RR) and Brassica oleracea (CC) with Brassica nigra (BB)

Brassica carinata (BBCC), a potential oilseed crop for dry land agriculture, is sensitive to high temperatures during germination and early stages of growth, which thereby restricts the possibility of using the residual soil moisture available after the rainy season for its cultivation. To overcome this problem, a three‐genome hybrid, RCBB, was synthesized using Raphanus sativus (RR) and Brassica oleracea (CC) as donor sources for the desired heat tolerance. Protoplasts of RC hybrids obtained through sexual crosses between R. sativus (female) and B. oleracea (male) were fused with protoplasts of Brassica nigra (BB) to produce RCBB somatic hybrids. The hybrid colonies regenerated with an average frequency of 7.6%. Twelve out of 36 hybrids grown to maturity were characterized for their nuclear and organelle genomes. While all the hybrids showed the presence of B. nigra chloroplasts, 10 of the hybrids showed B. nigra‐specific mitochondria and two had Raphanus‐spedfic mitochondria. The somatic hybrids could be backcrossed to B. carinata.     

异色瓢虫对菜缢管蚜、禾谷缢管蚜和白杨毛蚜的捕食作用

异色瓢虫是一种重要的捕食性天敌,可捕食多种蚜虫,在生物防治中具有很大应用前景。研究了异色瓢虫对3种蚜虫(即菜缢管蚜、禾谷缢管蚜和白杨毛蚜)的捕食功能反应。结果表明:异色瓢虫对3种蚜虫的日捕食量中,其中四龄幼虫最大,成虫和三龄幼虫次之,1、2龄幼虫最小。捕食者对猎物的功能反应均属于Holling-Ⅱ型方程。     

锌、锰对棉花吸收氮、磷养分的影响及机理研究

较高或较低浓度的土壤锌、锰影响棉花对氮、磷养分的吸收、而合适的土壤锌、锰浓度能促进棉花根系和地上部对氮、磷的吸收和积累。提高植株及茎、叶、蕾、铃中氮、磷的含量,对棉花的生产发育,产量及产量构成因素都表现出明显的促进作用,通过水培试验研究发明,锌、锰在一定浓度条件下所表现的促进作用,主要是提高了棉花植株的根系活力,增加棉株叶片的叶绿素含量,调节棉株体内的酶活性,从而增加了棉花对营养物质的吸收、运输和代谢、提高了氮、磷的利用率、增加棉花的产量。     

Photoperiod response in mungbeans (Vigna radiata (L.) Wilczek)

Summary Five strains of mungbeans were grown at 8-, 12-, 13-, 14-, 15-, and 16-hour photoperiods in plant environmental chambers. The strains did not differ in days to flower at the 8- and 12-hour photoperiods, but flowering was delayed and plant height increased differentially when the photoperiod was increased beyond 12 hours. Two strains exhibited only slight sensitivity over the range of photoperiods studied. Two strains failed to flower within a 180-day period at the 16-hour photoperiod. The results corroborate observations in the First International Mungbean Nursery in which 28 strains grown at low latitudes (short photoperiods) had a narrow range in days to flowering, with the range becoming wider at the higher latitudes (longer photoperiods). The results provide evidence that response to photoperiod is important in the adaptation of mungbean strains in different latitudes.Contribution No. 6890 from the Missouri Agricultural Experiment Station.     

Pollen storage in cocoyam (Xanthosoma sagittifolium (L.) Schott)

Summary The effect of different storage conditions on cocoyam pollen viability was investigated. Two levels of temperature (0° and 5°C) and four levels of relative humidity (0, 10, 20 and 30 percent) represented the storage environments.Viable cocoyam pollen could be obtained after 28 days in storage. The best storage condition was 5°C and 30% relative humidity.     

Utilization of flow cytometry for festulolium breeding (Lolium multiflorum (2x) × Festuca arundinacea (6x))

Festulolium is a hybrid between Festuca and Lolium species that has valuable agronomic traits from both grass species. The purpose of our breeding program is to produce hexaploid festulolium that introduces tolerance to summer depression into Italian ryegrass (Lolium multiflorum) by crossing it with tall fescue (Festuca arundinacea). However, we found the DNA ploidy of hexaploids was not stable and was reduced in successive generations. We aimed to find out how to obtain stable high-ploidy festulolium. F1 hybrids of L. multiflorum and F. arundinacea were produced. The F3 generation was produced from putative hexaploid F2 individuals by open pollination. The F4 to F6 generations were obtained by polycrossing. The DNA ploidy levels of F2 to F6 individuals were estimated by flow cytometry. Cytological characteristics of the F5 and F6 individuals were investigated by FISH and GISH. The DNA ploidy level of hexaploid festulolium was reduced and stabilized at almost the same level as a tetraploid. Seed fertility was inversely correlated with an increase in ploidy level. GISH revealed no preferential Lolium transmission. FISH with a telomere probe revealed that counting the exact number of chromosomes in festulolium was difficult. DNA ploidy level was strongly correlated with the number of chromosomes.     

Intercropping Studies in Lemongrass (Cymbopogon flexuosus) (Steud. Wats.)

Lemongrass ( Cymbopogon flexuosus (Steud.) Wats) is a perennial, multicut aromatic grass, which yields an essential oil used in perfumery and pharmaceutical industries and Vitamin A, has a long initial lag phase. To utilize the crop growth resources more efficiently during this phase, studies were made to explore the possibility of intercropping food legumes with lemongrass. An experiment conducted during 1992–93 revealed that the food legumes like blackgram ( Vigna mungo (L) Hepper), cowpea ( Vigna unguiculata (L) Walp) or soybean ( Glycine max (L) Merr.) could be intercropped in the initial stages of lemongrass to get extra yields over and above that of lemongrass, without affecting the yield of lemongrass.     

Effect of Diclofop and Linuron on Rye Grass (Lolium multiflorum), Control in Triticale (X Triticosecale), Wheat (Triticum aestivum), and Rye (Secale cereale)

Annual rye grass ( Lolium multiflorum Lam.) is a serious and wide spread problem in cereal crops. A field experiment with a promising herbicide diclofop [(±)-2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid] at 0.56, 0.84 and 1.12 kg ai/ha, in comparison to commonly used linuron [ N' -(3,4-dichlorophenyl)- N -methoxy- N -methylurea] at 0.84, 1.12 and 1.41 kg ai/ha was conducted to control rye grass ( Lolium multiflorum Lam.) in triticale (X Triticosecale Wittmack), wheat ( Triticum aestivum L.) and rye ( Secale cereale L.). The herbicides were applied as soil-incorporated, preemergence and post-emergence. Results showed that diclofop is less phytotoxic than Linuron and the postemergence application of these herbicides was more phytotoxic on all cereal crops. Diclofop applied at 1.12 kg/ha, gave almost 100 percent rye grass control and produced 45 and 115 kg/ha higher grain yields in pre- and postemergence methods, respectively, as compared to the soil-incorporated method.     

Origin and evolution of teosinte (Zea mexicana (Schrad.) Kuntze)

Summary The tripartite hypothesis postulates that cultivated maize was derived from a wild podcorn which was once indigenous to the lowlands of South America; that this wild Z. mays is now extinct; that Z. mexicana (teosinte) originated from natural hybridization of Z. mays and a species of Tripsacum after cultivated maize was introduced into Central America; and that most modern races of maize resulted from introgression of primitive maize with teosinte, Tripsacum, or both. This hypothesis has been criticized primarily on the basis that it involves too many theories for the available facts.The basic question that needs to be answered is whether maize was domesticated from a wild Z. mays or from Z. mexicana. The oldest known archaeological remains suggest that a wild Z. mays existed before Z. mexicana came on the scene. This question can only be settled by further archaeological research.Accepting the assumption that a species of Zea which is distinctly different from Z. mexicana gave rise to maize, however, does not necessarily lead to accepting a hybrid origin for teosinte. Judging from present day breeding behaviour, Z. mays and Z. mexicina are conspecific and only distantly related to Tripsacum. This cytogenetic similarity could be explained on the basis of extensive introgression between teosinte and maize. Introgression of germplasm from teosinte into maize is obvious wherever these taxa are sympatric. This pattern of a crop absorbing genes of its wild progenitor across a weedy race, is commonly encountered in all other cereals. Should this not be true in maize, it certainly will be a rare exception.The assumption that teosinte originated as a hybrid between domesticated Z. mays and a species of Tripsacum remains an intriguing possibility. However, after weighing the pros and cons of the available morphological and genetical evidence, the level of confidence with which this hypothesis can be excepted appears rather low.     

Hybrids of Bread Wheat (Triticum aestivum) with Thinopyrum scirpeum (4x) and Thinopyrum junceum (6x)

Hybrids were obtained by crossing Thinopyrum scirpeum (4x) and T. junceum (6x) onto Triticum aestivum cv, ‘Chinese Spring’. An average meiotic pairing of 24.44^I+ 5.07^II+ 0.14^IIIin the ‘Chinese Spring’×T. scirpeum hybrid (ABDE₁E²) is attributed to two similar genomes from T. scirpeum (E₁E₂E₃E₄). An average meiotic chromosome pairing in the other hybrid (ABDJ₁J₂E₃) was 31.70^I+ 3.80^II+ 0.90^III and is attributed to autosyndetic pairing between the three genomes of T. junceum.     

Analysis of glutamate oxaloacetate transaminase (GOT) isozyme variants in diploid tuberous Solanum; inheritance and linkage relationships to ds1 (desynapsis), y (tuber flesh colour), cr (crumpled) and yc (yellow cotyledon)

Summary Employing polyacrylamide gradient-gel electrophoresis, the genetic control of leaf glutamate oxaloacetate transaminase (GOT) isozyme variants and their linkage to ds1 (desynapsis), y (tuber flesh colour), cr (crumpled) and yc (yellow cotyledon) were studied in diploid tuberous Solanum species hybrids.Leaf GOT isozymes proved to be dimeric and under the control of two independently segregating loci (Got-1 and Got-2) with two (1 ^s , 1 ^f ) and three (2 ^s , 2 ^f , 2 ⁿ )alleles respectively. The 2 ⁿ allele was concluded to encode a 2 ^fallozyme subunit capable of forming heterodimeric but no homodimeric active molecules. As expected with Got-1 and Got-2 isozymes being localized in different cellular compartments, no intergenic heterodimer formation was observed.In contrast to earlier studies, a gradual rather than discrete transition between the tuber flesh colour classes white and yellow was observed in segregating progenies. Adopting a standardized classification method, however, monogenic recessive inheritance of white tuber flesh was confirmed. Got-1, ds1 and cr were found to represent a single linkage group. Among the presently studied marker loci no further linkages were detected. As to linkage analysis, the difficulties imposed by gametophytic incompatibility in nearly all diploid potato species and by the frequent occurrence of recessive (sub)lethal genes are discussed.     

N-(1-萘乙酰基)-N'-(4-氨替吡啉基)硫脲(NAT)对小麦生理活性影响的初步研究

以新合成的NAT配制成不同浓度(0.1、1.0、10.50mg·L~(-1))的水溶液,对小麦进行漫种、水培幼苗和大田灌浆期叶面喷洒处理,以与NAT相同浓度的NAA作对比,研究了喷后一定时期小麦叶片生理活性和收割时籽粒千粒重。结果表明,NAT使小麦在不同生长发育时期叶片中的叶绿素含量均增加;幼苗叶片呼吸速率下降;幼苗期低浓度处理NR活性增高,高浓度显著抑制,灌浆期则随处理浓度的升高而显著增加;籽粒千粒重明显高于对照。不论对叶片生理活性还是对籽粒千粒重的影响,NAT的总体效果均明显优于NAA,其中以1 mg·L~(-1)左右浓度的NAT处理效果最佳。     

The domestication and improvement of cowpeas (Vigna unguiculata (L.) Walp.)

Summary Physiological and morphological characteristics of the two wild and three domesticated subspecies of cowpeas are compared. The wild accessions are alike in having small, hard seeds borne in dehiscent pods, but differ in other characteristics. We suggest that the wild subsp. dekindtiana, from the seasonally-arid tropics, is more likely to have been the progenitor of modern cowpeas than the other wild subspecies (subsp. mensensis), but that subsp. dekindtiana was first cultivated in the humid tropics where its pods are slow to dehisce. Domestication has been associated with changes in the structure of pod valves and seed coats which reduce pod dehiscence and seed hardness. Pods and seeds have increased in size, mainly by increases in the rate of dry weight accumulation, and their increase has been only partly paralleled by increase in the area of subtending leaves. There has been no increase in the maximum photosynthetic rate of leaves, but the duration of their photosynthetic activity has increased. Domesticates are less sensitive than are wild plants to some environmental controls, such as in the response of germination to temperature, but in their flowering responses to daylength both wild and cultivated forms retain sensitivity under conditions where this is of adaptive value.     

米象和玉米象蜡层与护蜡层成分的气质联用鉴定

采用正己烷整体浸泡米象和玉米象成虫试虫的方法,在常温及超声波浴的条件下,对两种害虫体壁上表皮的蜡层和护蜡层成分进行提取,借助气质联用分析提取物成分.结果表明:米象蜡层和护蜡层提取物质含有7个组分,玉米象的提取物质中含有3个组分,主要是烃、含有羟基的酚类、带有羟基的酮类物质和酯类.两种害虫的提取物的总离子流色谱图具有明显差异,可以用于区别米象和玉米象.两种害虫蜡层和护蜡层共有成分分别是:1,2-苯二甲酸-1,2-(2-甲基-1)-丁醇二酯、正二十烷和1,2,4-苯三甲酸-(4-正十二醇酯)-1,2-甲二酯,它们可能具有象虫属的特征.米象蜡层和护蜡层的特征成分可能是1,1-二苯基-2-甲基-3-(2-环戊烯基)-1-丙烯、3,5-二(1,1-二甲基乙基)-4-羟基-2,4-环二烯酮、3,5-二(1,1-甲基乙基)-1,2-苯二酚和1,2,4-苯三甲酸-1,2-甲二酯,具有米象种类的特征鉴别意义.因此,利用气相色谱与质谱联用技术,分析研究玉米象及米象的体壁表皮蜡层和护蜡层成分,进行米象和玉米象近缘种的鉴别和昆虫分类具有良好的实际应用前景.     

Inheritance of seed size in cowpea (Vigna unguiculata (L.) Walp.)

Summary The inheritance of seed weight in cowpea was examined in a field planting of the parents, reciprocal F₁s, F₂s and backcrosses to both parents of a cross between TVu 1977-OD (small seeded) and ACC 70002 (large).Seed weight was inherited quantitatively and small seed was partially domiminant to large seed size. Gene action was predominantly additive but dominance and additive × additive epistatic effects were also significant.Broad and narrow sense heritabilities were 85.1±5.3% and 75.4±18.6% respectively. The minimum number of loci involved in the inheritance of seed size was eight, and each gene pair contributed up to 1.02 g increase to seed weight. The estimate of genetic advance from F₂ to F₃ generations with 5% selection intensity was 3.58 g.International Institute of Tropical Agriculture, Semi-Arid Food Grain Research and Development Project/National Cowpea Improvement Program, B.P. 1783, Ouagadougou, Upper Volta.Department of Primary Industries, Hermitage Research Station, Warwick 4370, Queensland, Australia.International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), ICRISAT Center, Patancheru, P.O. 502 324, A.P., India.     

Wide hybridization between wheat (Triticum L.) and lymegrass (Leymus Hochst.)

A total of 240 F₁ hybrids was made beween wheat (Triticum aestivum L. em. Thell. (2n = 6x = 42) and T. carthlicum Nevski (2n = 4x = 28)) and perennial lymegrass (North European Leymus arenarius (L.) Hochst. (2n = 8x = 56) and North American L. mollis (Trin.) Pilger (2n = 4x = 28)). The wide crosses yielded embryos in 20% of caryopses and 96% of the embryos developed into normal hybrid plants. The hybrids were vegetatively vigorous, with evidence of the Leymus rhizomatous habit. Those deriving from L. arenarius survived overwintering in Iceland, but the hybrids L. mollis did not, whereas in a milder environment, both showed perenniality. Cytogenetic analysis of root tip cells before the plants were treated with colchicine showed that 21 out of 28 hybrids investigated had chromosome mosaics, with a population of both amphihaploid and amphidiploid cells. This spontaneous doubling of somatic chromosomes occurred in all cross combinations, with the highest average frequency of diploid cells (28%) in T. carthlicum × L. arenarius crosses. A few selfed seeds have been obtained from a T. aestivum × L. arenarius hybrid. All the hybrids were treated twice with colchicine, but the treatment appeared to have little or no effect on the frequency of chromosome doubling in the hybrids deriving from T. aestivum. The frequency of diploid cells, however, increased significantly (e.g. to 80%) in the hybrids deriving from the T. carthlicum parent. Genomic in situ hybridization confirmed the hybridity of the plants and showed that the hybrids were amphiploids containing genomes of both wheat and lymegrass. In situ hybridization using ribosomal DNA probe differentiated chromosomes of L. mollis, L. arenarius from those of wheat. The hybrids are being backcrossed with lymegrass pollen, aiming to domesticate the wild, perennial species. This revised version was published online in July 2006 with corrections to the Cover Date.