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1.
T. M. Choo 《Euphytica》1984,33(1):177-185
Summary Three double-cut red clover (Trifolium pratense L.) varieties: Prosper I, Florex, and Tristan each with two different seedlots were space-planted in a field. The total number of plants established for each seedlot was about 900. In the seedling year, plants were classified into five growth types according to rosette development and flower production. In the fall of the third year 14% of the rosette-forming, non-flowering Type 1 plants were alive; 8–11% of the intermediate types survived; and only 2% of the nonrosette-forming, profusely flowering Type 5 plants remained growing. The non-flowering class (Types 1 and 2) persisted better than the flowering class (Types 3, 4, and 5). This difference in persistence was similar for all three varieties regardless of seed source. The two flowering classes, in the production years, had the same proportion of the most vigorous plants. The most vigorous plants of the non-flowering class had the same frequency distribution of seed yield as those of the non-flowering class. In conclusion, the flowering response can be used as a selection criterion for persistent plants; and plants not flowering in the seedling year can attain a forage and seed yield as high as flowering plants in the production years. Screening for non-flowering plants can be carried out at the seedling stage in the greenhouse before seedlings are transplanted to the field.Contribution No. 520, from the Charlottetown Research Station, Agriculture Canada, Prince Edward Island, Canada. 相似文献
2.
J. De Jong 《Euphytica》1981,30(2):493-500
Summary
Chrysanthemum morifolium seedlings and cuttings from those seedlings were grown to flowering at 17°C, short days (8 h) and two levels of irradiance (10 and 30 W m–2). The cuttings flowered more readily than the seedlings at both irradiances, Especially at 10 W m-2 many seedlings remained vegetative. The delay in flowering of the seedlings was accompanied by a higher number of leaves produced before flowering.The number of leaves produced by the seedling in excess of the number of leaves produced by the cutting from that seedling varied considerably between genotypes. The correlations between seedlings and the corresponding cuttings for days to flowering and number of leaves were low but generally significant.It is concluded that cuttings are preferred over seedlings in breeding programmes that aim at developing chrysanthemums for low light winter production. 相似文献
3.
Summary The aim of this study was to correlate flowering response of tetraploid red clover (Trifolium pratense L.) in the year of seeding with winter survival and other characteristics (vigour, bloom date). In two different years about 2000 plants of two different cultivars (Hungaropoly and Tapiopoly) were established and in the fall were classified into five growth types based on rosette formation and flower production. Non-flowering types were shorter and had few petioles at 6–8 weeks of age, but showed better survival than flowering types. Hungaropoly non-flowering types were more vigorous and bloomed earlier in the second year but Tapiopoly non-flowering types were less vigorous and bloomed later. Although non-flowering in the seeding year was associated with better survival in the second year, there was adequate variation within both types for selection for improved persistence. 相似文献
4.
Three commercial varieties of flue-cured tobacco viz., Chatham, Delcrest and Hicks were subjected to neutron irradiation using six different doses ranging from 1×1012 to 5×1013 N/cm2/sec. The N1 generation was grown in the field during 1959–60. Only plants from the lowest two doses viz., 1×1012 and 2.5×1012 N/cm2/sec. survived in the field up to the adult stage. From this material, normal plants with high pollen fertility were selected for testing their performance in replicated trials.The progenies of the selected plants were raised in the field during 1960–61. The data collected showed that although there were no significant differences in the means in some characters there was a significant shift in the variance among treated plants as compared to the control. Advantage was taken of this greater variance among the treated progenies and selections were made for certain specific characters viz. narrow leaf and long internodes in Chatham, broader leaf, late flowering and greater leaf number in Delcrest and Hicks.A new leaf mutant in the variety Delcrest was isolated which was found to be agronomically superior to the untreated control. This mutant is characterised by hooding of the leaf tip and is designated leaf tip hooded.Replicated trials were conducted for the narrow leaf and long internoded types in Chatham, the leaf tip hooded in Delcrest and the late flowering selections in Hicks, during 1962–63. The narrow leaf selection in Chatham bred true. The long internode type was found to be segregating. The leaf tip hooded mutant in Delcrest was found to breed true and has also maintained its superior performance.The achievements and scope of the mutation breeding programme in flue-cured tobacco have been broadly discussed. 相似文献
5.
Summary Early flowering carnation cultivars, responding to artificial long days, can assist the grower to plant the onset of flowering and achieve a better distribution of flower production over the year.A comparative trial is described of 20 carnation genotypes (cultivars and backcrosses of interspecific hybrids), representing a wide variation in flowering time and response to long days. The trial was planted in September in a phytotron under a winter light intensity of 15 W/m2 for eight hours per day. In one half of the trial, daylength was increased to 24 hours for 25 days in December-January. At the end of February the plants were transferred to a glasshouse where they were observed until all primary shoots had flowered. The main purpose of the experiment was to analyse the genetic factors responsible for the large differences in flowering behaviour between genotypes. Average flowering dates varied from 132 days from pinching in a Dianthus chinensis hybrid to 181 days in the mediterranean cultivar Raggio di Sole. LD response was most pronounced in the earliest flowering Diantini selections and least in the traditional commercial cultivars. In the former the LD effect was evident in all shoots of a plant, but mostly so in the lower (older) shoots; in the traditional cultivars only the higher placed shoots responded to LD. As a result, the proportion of the shoots actually responding to LD varied from 28% in the traditional cultivars to 54% in the Diantini x D. Allwoodii cv Doris group of genotypes. 相似文献
6.
Summary This study assessed 46 potato cultivars, breeding lines and Solanum spp. for heat-tolerance using short-term growth rates and carbon assimilation measurements of young in-vitro-derived plants. Plants of the 46 clones and species were transferred from greenhouse conditions to controlled conditions set at 33/25°C day/night with 12 h photosynthetic photon flux density (PPFD) at 430–450 mol m-2s-1 and an 8 h daylength extension (6 mol m-2s-1), to inhibit tuberization. Twenty eight accessions were also grown in a 20/10°C controlled environment. Plants were harvested after 10 and 20 days and dry weights of the plant components were measured for plant growth analysis. Gas exchange (leaf net photosynthesis and maintenance dark respiration) and leaf chlorophyll fluorescence parameters (O, P, and T) were measured at 30°C. Amongst the 30 accessions grown at both hot and cool temperatures, only two accessions (Yungay and AVRDC 1287.19) produced more dry weight in the hot chamber than the cool chamber. Hot/cool ratioss for net assimilation rate (NAR) and relative growth rate (RGR) exceoded unity in five and six accessions, respectively. For the 46 accessions grown under hot conditions, none had significantly greater values than those of the control clones for RGR and NAR. Differences between clones in maintenance respiration and net photosynthesis were more closely related to RGR, NAR, and total dry weight (TDWT) in clones which invested more dry weight in leaves and less in stems. Attributes of the chlorophyll fluorescence curve did not explain more of the clonal variation in RGR, NAR, and TDWT than did gas exchange parameters. No single gas exchange or fluorescence character explained more than 50% of the variability among clones for NAR, RGR, or TDWT, but combination of favourable attributes could improve potato heat tolerance in the future. 相似文献
7.
The propagation of cassava through true seeds (sexual seeds) rather than by clones is a promising option due to its manifold advantages such as enhancing the multiplication rate, keeping the dreaded cassava mosaic disease (CMD) under check, longer seed viability, ease of storage and transport. The high genetic heterogeneity and consequent variation among seedlings is the major stumbling block in sexual propagation. In the present study, a CMD resistant exotic accession MNga-1 and a promising cultivar Ambakadan with profuse fruit setting, seed output and male sterility were identified to be promising parents for the TCS programme. The rate of sexual propagation could be more than 20-fold over the traditional clonal propagation. Seed treatment with 1% KNO3 or 300 ppm GA promoted uniform seed germination and seedling vigour and reduced the transplanting period from 45 days after planting (DAS) to 30 DAS. Removal of taproots of seedlings while transplanting enhanced tuber development. Tuber yield of first clones (C1) was significantly superior to that of the seedlings. The dry matter content and starch output of seedlings and first clones were comparable to that of the commercial varieties. Similarly, the HCN and cooking quality of seedlings and first clones were at acceptable levels. In the open pollinated (OP) progenies of the Ambakadan the CMD infection increased drastically due to secondary spread of the pathogen. The hybrid progenies of Ambakadan and the CMD resistant line MNga-1 revealed higher percentage of CMD free seedlings and first clonal progenies in the evaluation trials conducted at CTCRI Thiruvananthapuram and ARS, Peddapuram during 2001–2002 and 2002–2003. Nearly homogeneous hybrid population resistant to CMD could be obtained by systematic roguing at seedling and first clonal stage. 相似文献
8.
Embryogenic calli derived from anther cultures of the two-rowed winter barley cultivar Igri were plated on solid L3 medium containing the proline analogue hydroxyproline (Hyp), 10–20 mmol l–1. Exposure to Hyp caused severe degeneration of most of the calli. Hyp resistant calli, distinguishable by their lighter colour and higher growth rate, and control calli not exposed to Hyp were plated on L3 regeneration medium. From 22,500 anthers exposed to Hyp 46 Hyp resistant regenerates were obtained, which were transferred to soil. After cultivation for 5–10 weeks at normal growth conditions they were cold hardened at 2 C under short day conditions together with control regenerates. Frost tolerance assays with segments of fully grown leaves of unhardened and cold hardened plants revealed that Hyp resistant regenerants were significantly more frost tolerant than the control regenerants. Improved frost tolerance was found also in the progenies R1 to R9, and genotypic segregation in the R1 generation in a 1:2:1 ratio was indicated. Increased proline content was observed in the R2 generation and in subsequent generations and was significantly (P 0.001) correlated with increased frost tolerance in the Hyp lines. Comparative studies of R9 progenies from homozygous R2 plants with the wild type Igri under field conditions in winter at three locations in Europe as well as crossing experiments confirmed the heritable improvement of frost tolerance and winter survival, respectively, in the Hyp lines. The results support the hypothesis that proline accumulation in cold acclimated winter barley plants is causally related to the acquisition of frost tolerance. Moreover, the described biotechnological procedure may be applicable in breeding programs for improved winter hardiness and possibly also for other stress tolerances. 相似文献
9.
Summary The partial resistance to leaf rust (Puccinia hordei) of 40 West-European spring barley cultivars was measured in plots isolated from one another to reduce inter plot interference. The leaf area affected by leaf rust was also measured in small plots of 0.5 m2 adjacent to each other, and on individual plants. The latent period was measured in the seedling stage and the adult plant stage, the infection frequency in the seedling stage only. The cultivars varied widely for partial resistance, many cultivars carrying a considerable level. Both the small adjacent plots and the single plants showed a marked inter plot interference strongly reducing the difference between cultivars. H wever, the ranking order of the cultivars was hardly, if at all, affected. Both latent period and the infection frequency showed large differences between cultivars, the latent period in the adult plant stage being highly correlated (r=0.82) with partial resistance, infection frequency in the seedling stage only rather weakly (r=–0.33).Selection for partial resistance appeared very effective in all stages tested; the seedling, the single adult plant, and the small plot stage. Selection in the small plot stage was the most effective followed by selection in the seedling stage. Selection for partial resistance therefore appears very well possible at all stages of the selection program. 相似文献
10.
Summary Twenty-one genotypes of cowpea (Vigna unguiculata), comprising landraces and varieties, were grown in 22 photothermal environments in Nigeria and Niger, West Africa, and a stability analysis of days from sowing to flowering (f) was carried out. Cowpeas are rarely insensitive to photoperiod; they are typically quantitative shortday plants wherein f is delayed when photoperiod (P) is longer than the critical photoperiod (P
c
). Therefore, in order to quantify genotypic variation in temperature sensitivity, genotype f was regressed against the mean trial f in circumstances where P
c
(i.e. approximately 13 hd-1) and mean temperature (T) was between 19° and 28° C. Correspondingly, in order to assess genotypic variation in photoperiod sensitivity, trials where T was near optimal (25°–28° C) but where P ranged from 10–14.5 hd-1 were used. These stability analyses detected no significant differences (P>0.05) between genotypes 9n temperature sensitivity but revealed significant differences (P<0.001) in photoperiod sensitivity. Regression coefficients from the stability analysis were strongly correlated (r=0.94, 19df) with a photoperiod sensitivity constant, c, determined from a photothermal flowering model. A stability analysis of f from field trials can therefore identify and quantify genotypic variation in response to temperature and photoperiod in cowpea.Abbreviations
f
days from sowing to flowering
- P
mean photoperiod
- P
c
critical photoperiod
- P
ce
ceiling photoperiod
- T
mean temperature
- T
b
base temperature
- T
o
optimum temperature
- SDP
short-day plant 相似文献
11.
Intergeneric hybrid plants between Colchicaceous ornamental plants, Sandersonia aurantiaca and Gloriosa rothschildiana, have successfully been produced via ovule culture. After 5 days of reciprocal cross-pollination, a few pollen tubes were observed in the ovary. Although seeds were obtained in both reciprocal cross-combinations, they did not germinate under ex vitro conditions. Ovules with placental tissues isolated 14 days after cross-pollination of S. aurantiaca × G. rothschildiana were cultured on a medium containing 0.01 mg l–1 each of -naphthaleneacetic acid (NAA) and 6-benzyladenine (BA), on which 41.5% of ovules swollen and produced callus-like structures within 10 weeks. When such swollen ovules were transferred to a medium containing 0.1 mg l–1 each of NAA and BA, 7.5% of the initially cultured ovules produced rhizome-like structures within 6 weeks. Among the rhizome-like structures, those derived from two independent ovules (3.7% of the initially cultured ovules) produced multiple shoots following transfer to a medium containing 0.25 mg l–1 NAA and 2.5 mg l–1 BA. Multiple shoot-derived plantlets were established on a plant growth regulator-free medium, and they were successfully transplanted to pots. Early verification of their hybridity was accomplished by flow cytometry (FCM) analysis, chromosome observation and rDNA analysis. 相似文献
12.
I. P. King K. A. Cant C. N. Law A. J. Worland S. E. Orford S. M. Reader T. E. Miller 《Euphytica》1996,89(1):103-106
Summary Wheat varieties tend to be chromosomally unstable producing on average 2–3% of plants with abnormal chromosome numbers. A number of semi dwarf wheat varieties, carrying the gibberellic acid insensitive dwarfing genes Rht1 or Rht2, have been seen to produce distinct tall off types due to reduction in dosage of the chromosome carrying the dwarfing gene. The UK variety Brigand, carrying Rht2 on chromosome 4D, produced very distinct tall off types when this chromosome was reduced in dosage. The frequency of tall off types was sufficiently high to cause the variety to fail United Kingdom statutory uniformity tests. An attempt to prevent the loss of chromosome 4D was made by constructing translocation chromosomes involving the short arm of chromosome 4D, which carries Rht2, and the long arm of chromosome 4S
l
from Aegilops sharonensis, which carries a gene(s) conferring preferential transmission. The work in this paper describes the field evaluation of two lines carrying 4DS.4DL-4S
l
L translocations, and demonstrates their success in preventing spontaneously occurring monosomy of chromosome 4D in semi-dwarf wheats. 相似文献
13.
Summary One 3-to 5-year clonal and two recent seedling-derived populations of white yam cultivars were grown and studied for the association of sex, flowering intensity, number of fruits and seed yield with vegetative characters and tuber yield. Yield was lowest in non-flowering plants and increased in the following order: male, monoecious and female plants; with females yielding almost twice as much as the non-flowering plants. The plants produced from small tuber setts, with higher leaf virus infection, low plant leafiness either had low flowering intensity, fewer fruits and seeds or even failed to flower. The sequence and timing of vegetative and reproductive processes in relation to the difference in yield between male and female plants is discussed. There is a strong indication that the intensity of flowering and fruiting is lower in plants from previous vegetative propagation compared to recent seedling-serived clones. 相似文献
14.
Summary These investigations were conducted to determine the effectiveness of first- and second-season selection programs for increasing forage and seed yield in kura clover (Trifolium ambiguum Bieb.).Rhizo kura clover, the base population, was grown as spaced plants in two programs for six generations of selection for flowering in the seedling and second seasons. Remnant seed for each generation of selection was used to establish spaced plant and broadcast evaluation trials.The first-season selection program was effective in increasing flowering not only in the first season, but for two subsequent seasons. The second-season selection for flowering had little or no effect. However, vigor, forage and seed yields were not increased by either program, and the first-season program progressively reduced vigor and forage yields as generations of selection increased. The cause of this is unknown but may be associated with inbreeding depression or detrimental physiological effects of first-season flowering. Reselection to eliminate possible inbreeding effects is being conducted to further examine the possibility of increasing seedling and aftermath vigor in kura clover. 相似文献
15.
Summary Interspecific hybrids were generated from crosses between 4 Zinnia angustifolia clones (maternal parents) and an inbred line of Z. elegans Orange King (paternal parent) to investigate the influence of Z. angustifolia genotype on morphology and flowering of hybrids. Leaf length, leaf width, flower diameter, number of ray petals, and days to flowering of interspecific hybrids were significantly influenced by Z. angustifolia clonal genotype. Genetic analysis of hybrid morphology and development was performed using 2 parental Z. angustifolia clones and 18 F1 (9 seedlings from each of 2 populations generated from reciprocal crosses between parental clones) as maternal parents in crosses with Z. elegans Orange King. Genotype of Z. angustifolia significantly affected plant height, fresh weight, number of nodes, and days to flowering of interspecific hybrids. Control of these traits was through the Z. angustifolia nuclear genome. Improvement in interspecific hybrid morphology or development, i.e., shorter stature, earlier flowering, or larger flowers, may be possible by selection of superior-performing Z. angustifolia clones as parents. 相似文献
16.
G. Delogu C. Lorenzoni A. Marocco P. Martiniello M. Odoardi A. M. Stanca 《Euphytica》1988,37(2):105-110
Summary The effect of a recurrent selection procedure was evaluated in a winter barley (Hordeum vulgare L.) population. Cycle zero (C0) was initiated by crossing six high yielding winter barley cultivars with the short straw cv Onice. The F1's were crossed according to a diallel scheme without reciprocals. A total of 750 S0 plants were derived and evaluated; 329 S0 plants were selected and their progenies (S1 lines) tested. Fifteen S1 lines were chosen and used as parents of cycle 1 (C1), by producing 105 F1 hybrids which simulated a random mating offspring. One hundred and three randomly chosen S1 lines belonging to C0, and 103 S1 lines belonging to C1, were evaluated at two locations.For grain yield a significant difference between cycles was observed. From C0 to C1 the grain yield increased with 307 g/m2. This increase was due to a higher number of seeds per m2. For plant height, heading date and 100-kernel weight no differences between cycles were observed.The positive results obtained in this study indicate the potential usefulness of recurrent selection for developing parents or lines superior for grain yield, with little change in other important agronomic traits. 相似文献
17.
G. Spangenberg Z. Y. Wang G. Legris P. Montavon T. Takamizo R. Pérez-Vicente M. P. Vallés J. Nagel I. Potrykus 《Euphytica》1955,85(1-3):235-245
Summary Intergeneric symmetric and asymmetric somatic hybrids have been obtained by fusion of metabolically inactivated protoplasts from embryogenic suspension cultures of tall fescue (Festuca arundinacea Schreb.) and unirradiated or 10–500 Gy-irradiated protoplasts from non-morphogenic cell suspensions of Italian ryegrass (Lolium multiflorum Lam.). Genotypically and phenotypically different somatic hybrid Festulolium mature flowering plants were regenerated.Species-specific sequences from F. arundinacea and L. multiflorum being dispersed and evenly-represented in the corresponding genomes were isolated and used for the molecular characterization of the nuclear make-up of the intergeneric, somatic Festulolium plants recovered. The irradiation of Italian ryegrass protoplasts with 250 Gy X-rays prior to fusogenic treatment favoured the unidirectional elimination of most or part of the donor chromosomes. Irradiation of L. multiflorum protoplasts with 500 Gy produced highly asymmetric (over 80% donor genome elimination) nuclear hybrids and clones showing a complete loss of donor chromosomes.The RFLP analysis of the organellar composition in symmetric and asymmetric tall fescue (+) Italian ryegrass regenerants confirmed their somatic hybrid character and revealed a bias towards recipient-type organelles when extensive donor nuclear genome elimination had occurred.Approaches aimed at improving persistence of ryegrasses based on asymmetric somatic hybridization with largely sexually-incompatible grass species (F. rubra and Alopecurus pratensis), and at transferring the cytoplasmic male sterility trait by intra- and inter-specific hybridization in L. multiflorum and L. perenne, have been undertaken.Abbreviations cpDNA
chloroplast DNA
- CMS
cytoplasmic male sterility
- 2,4-D
2,4-dichlorophenoxy-acetic acid
- IOA
iodoacetamide
- mtDNA
mitochondrial DNA
- RFLP
restriction fragment length polymorphism 相似文献
18.
G. Bremer 《Euphytica》1961,10(2):229-243
In this article a survey is given of interspecific crossing in Saccharum leading to sugar cane forms with chromosome numbers on a level of 2n=about 160.Breeding for immunity in sugar cane, in Java practised since 1893, led in the twenties to sugar cane forms, in which resistance to diseases was attended by a very high sugar yield. These canes, belonging to the so-called third and fourth Saccharum spontaneum nobilisation with chromosome numbers of 2n=about 100 to 120, formed the starting point in 1925 of a step-by-step crossing procedure leading to sugar cane clones third nobilisation new style with chromosome numbers that in comparison with 2n=80 of Saccharum officinarum could be regarded as tetraploids.In 1938, when such sugar cane forms with 2n=about 160 were created in a comparative large number of cases, the author projected a six-year plan for the years 1939–1944 with the purpose of obtaining such plants in very large numbers from numerous cross combinations. This was necessary since the best clones resulting from it had to be compared with the best clones of the third nobilisation old style, themselves being products of a large number of crossing experiments covering many years. This six-year plan was never fulfilled in consequence of the second world war.The fact remains, however, that during the years 1925–1939 in Saccharum polyploidy breeding was executed without the aid of colchicine, resulting in well developed plants with 2n=about 160 chromosomes. Several plants of the first nobilisation1) n.s. with such chromosome numbers even could be called giants.As result of this investigation it ought to be mentioned also that plants with 180 to 220 chromosomes without exception were poor plants. In these cases the optimum chromosome number must have been surpassed. 相似文献
19.
Within family genetic and environmental variabilities in oil palm dura (D) ×pisifera (P) hybrid progenies were estimated from a D × P progeny test trial, a clonal trial and a clonal cum D × P progeny test trial
and with the objective of examining the efficiency of selecting source palms (ortets) within family for clonal propagation.
The clones were derived from seedling embryos or seedlings that were progeny reproductions of families proven in the first
trial. The progenies in the second trial represented the source families of two sets of clones planted in the same trial.
Estimates were obtained from: between and within family variance components; between and within clone variance components;
and difference between pooled within family variance and pooled within clone variance. Estimates were generally similar with
the different methods used. Within family genetic variabilities were generally low in progenies derived from more inbred parents
especially in bunch and oil yields. In progenies from more outbred or variable parents, within family genetic variabilities
were relatively higher particularly for oil to bunch and palm height; nevertheless environmental variabilities predominated.
The low efficiency of within family palm or ortet selection for clone production and the need for repeated clonal tests over
time and space to identify outstanding clones are stressed and the implications to commercial clonal propagation of oil palm
discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Summary Anther culture of 10 tetraploid wheat (Triticum turgidum) genotypes and two backcross lines representing a wide range of genetic variation was studied in a randomized block design with three replications. Each replication consisted of 2 pots with 3 plants. The day length was 16h and temperature 25° C/15°C for day/night in a controlled greenhouse where the anther donor plants were grown. Two different treatments were used for anther culture. The first one was potato 2 medium (Chuang et al., 1978) modified by adding 0.5 mg/l glutamine and solidified by gelrite (4g/l) (Henry & De Buyser, 1981). Cultures were incubated in light (15 E m–2 S–1) at 26°C at 16h day length. The second medium was described by Fadel & Wenzel (1990), differing from the first by the nature of the sugar (maltose) and consistency of the medium (semiliquid by ficoll). Anther cultures were incubated in the dark at 28°C. The study of about 1300 anthers per genotype and treatment showed that both genotype and treatment affected embryo formation of tetraploid wheat. The backcross lines exhibited significant differences for androgenic abilities when compared to their common parent. Most of the genotypes were medium dependent for androgenesis and revealed significant interactions with the two treatments. Five green plantlets were regenerated and fertile doubled haploid plants were obtained from three out of the 12 studied genotypes. 相似文献