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1.
Hemp (Cannabis sativa) has a highly variable sexual phenotype. In dioecious hemp, the sex is controlled by heteromorphic sex chromosomes according to an X-to-autosomes equilibrium. However, in monoecious hemp, the sex determinism remains widely unknown and has never been related to a quantitative approach of sex expression. The present paper aims to contribute to the comprehension of the sex determinism in monoecious hemp by assessing the genotypic variability of its sex expression and establishing its sex chromosomes. Five monoecious and one dioecious cultivars were grown in controlled conditions under several photoperiods. The monoecy degree of 194 monoecious plants was recorded at each node by a figure ranging from 0 (male flowers only) to 6 (female flowers only). The genome size of 55 plants was determined by flow cytometry. The DNA of 115 monoecious plants was screened with the male-associated marker MADC2. The monoecy degree varied significantly among monoecious cultivars from 3.36 ± 2.28 in ‘Uso 31’ to 5.70 ± 0.81 in the most feminised ‘Epsilon 68’. The variation of monoecy degree among cultivars remained consistent across trials despite a significant “cultivar × trial” interaction and partly agreed with their earliness. The genome size of monoecious plants (1.791 ± 0.017 pg) was not different from that of females (1.789 ± 0.019 pg) but significantly lower than that of males (1.835 ± 0.019 pg). MADC2 was absent from all monoecious plants. These results strongly support that cultivars of monoecious hemp have the XX constitution and that their sex expression has a genetic basis.  相似文献   

2.
DNA from female and male hemp (Cannabis sativa L.) plants belonging to nine different varieties were screened with180 RAPD primers in a search for sex-associated DNA markers. About 1500bands were produced in total, nine primers were found yielding one or two DNA bands amplified in all nine male DNA bulks and absent in all female DNA bulks. These putatively male-associated markers were then scored in three different F1progenies, deriving from a cross between a common male parent and three different female plants. The sex of the progeny was accurately scored on the basis of the floral phenotype, and the presence of the nine male-associated markers was verified by RAPD analysis. In all three progenies examined, all the male plants showed the DNA markers previously identified by bulk segregant analysis (BSA) on the hemp varieties, while all the female plants lacked them. The fact that the association between these markers and the staminate phenotype is found when examining male plants of distantly related varieties, and that such linkage is never broken when different progenies are examined, strongly supports the hypothesis that the markers found are physically located on the Y chromosome, in a region excluded from recombination during meiosis. Another marker was shown to be present in the male parent, in all the male plants of each progeny, and in 50% of the female progenies, while it was absent in the female parent; the possible occurrence of markers deriving from multiple amplification sites of the genome is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

3.
Novel male-specific molecular markers (MADC5, MADC6) in hemp   总被引:8,自引:0,他引:8  
Decamer RAPD primers were tested on dioecious and monoecious hemp cultivars to identify sex-specific molecular markers. Two primers (OPD05 and UBC354) generated specific bands in male plants. These two DNA fragments were isolated, cloned and sequenced. Both markers proved to be unique, since no sequence with significant homology to OPD05961 and UBC354151 markers were found in databases. These markers were named MADC3 (OPD05961) and MADC4 (UBC354151) (Male-Associated DNA from Cannabis sativa). The markers were converted into sequence-characterized amplified region (SCAR) markers. The SCAR markers correlated with the sex of the segregating F2 population and proved the tight linkage to the male phenotype. Results of F2 plant population analysis suggest these markers are to be linked to the Y chromosome. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

4.
Flowering phenology and sexual dimorphism are two major features that affect stem and seed production in hemp (Cannabis sativa L.), a short-day naturally dioecious plant. The sowing time is of primary importance because it affects flowering time and thereby influences stem yield. In spite of their unstable sexual phenotype, monoecious cultivars facilitate the harvest of both stems and seeds by reducing crop heterogeneity. The main objective of this paper was to determine the stem and seed yields for five monoecious hemp cultivars in relation to their flowering phenology and sex expression. Sowing was carried out on five distinct dates during 2007 and 2008 at two sites in Belgium. The duration from sowing to flowering in days, both stem and seed yields and the seed harvest index decreased when sowing was postponed from mid-April to the end of June. The stem and seed yields from the mid-April sowing (approximately 12.5 and 1.9 t ha−1, respectively) were within the ranges that were reported for fibre and both fibre and seeds production, respectively, in monoecious hemp. No interaction was observed between the sowing date and cultivar for both yields. Sex expression varied among cultivars, indicating that it might be selected, and was partly linked to earliness. Stem yields were lowest in the earliest cultivar (Uso 31) and highest in the latest one (Epsilon 68) while seed yields were lowest in the most masculinized and earliest cultivar (Uso 31) and highest in the most feminized and early (Fedora 17) or mid-early (Felina 32) ones. Both stem and seed yields correlated best with the duration from sowing to full female flowering or from sowing to the end of male flowering.According to our results, harvesting the seeds in addition to the stems in monoecious hemp requires early sowing and the selection of feminized early or mid-early cultivars, earliness depending on the climatic conditions in the cultivation area. Therefore, it might be agriculturally valuable to take sex expression into account in addition to earliness during the selection of cultivars that are adapted to a dual purpose.  相似文献   

5.
Summary Fibre formation in hemp (Cannabis sativa L.) is a dynamic process. In order to follow this process, the chemical composition of the hemp stem was studied during plant development using the acid and neutral detergent fibre and lignin methods. Additionally, near infra-red spectroscopy was carried out. To predict the chemical composition of the stem samples partial least square (PLS) analysis was carried out. The developed PLS models can predict the level of %ADF and %NDF in the hemp bast and core samples. For %ADL, the models are only suited for either core or bast tissues and can not be used for both tissues simultaneously.  相似文献   

6.
There is a recent surge in the marker‐assisted selection of desired sex type among economically important dioecious crops. Simmondsia chinensis (Jojoba), a dioecious crop is of immense agricultural importance where only the female plants are preferred for commerce. DNA fingerprinting technology, ISSR analysis along with bulk segregant analysis (BSA), has been carried out on a diverse set of 17‐ to18‐year‐old mature male and female plants of Jojoba to validate a male sex‐specific ISSR marker, UBC‐8071200 on larger population that comprises 330 female and 255 male plants of Jojoba. This male sex‐specific DNA fragment of ~1200 bp was cloned and sequenced. The sequence was found to be 1120 bp in length and based on the sequence information, a pair of sequence tagged sites primers was developed that amplified a single ~800 bp band, consistently only in all the male populations while no amplification was seen in their female counterparts. The marker was named as Jojoba Male Sex Marker which was further validated on 330 female plants from 22 genotypes and 255 male plants from 17 genotypes.  相似文献   

7.
Sex expression is of primary importance for the genetic improvement and production of monoecious hemp: masculinized phenotypes are associated with higher fungal sensitivity, and feminized phenotypes with higher seed yields. However, sex expression varies quantitatively among plants and nodes and with time. Here, we developed eight variables that characterize the sex expression in monoecious hemp to dissect its genetic determinism. The monoecy degree (MD), ranging from 1 (mostly male flowers) to 5 (mostly female flowers), was recorded for each node of 167 plants, at 6 times at 1‐week intervals. Two types of longitudinal variables were constructed: ‘synthesis’ (mean MD and percentages of nodes of each MD) and ‘structure’. The latter consisted of the parameters of a logistic curve describing MD as a function of the node position. An r‐square of 0.97 was obtained between the estimated and observed MD values, and the logistic parameters were weakly correlated with each other and with the synthesis variables. Therefore, we conclude that the present modelling approach is relevant for characterizing the sex expression in monoecious hemp.  相似文献   

8.
This paper aims to clarify the genetic mechanism that is responsible for the accumulation of cannabigerol (CBG) in certain phenotypes of Cannabis sativa L. CBG is the direct precursor of the cannabinoids CBD, THC and CBC. Plants strongly predominant in CBG have been found in different fibre hemp accessions. Inbred offspring derived from one such individual were crossed with true breeding THC predominant- and CBD predominant plants, respectively. The segregations in the cross progenies indicate that CBG accumulation is due to the homozygous presence of a minimally functional allele, tentatively called B0, at the single locus B that normally controls the conversion of CBG into THC (allele BT) and/or CBD (allele BD). The fact that CBG accumulating plants have so far been found in European fibre hemp populations that are generally composed of BD/BD plants, and the observation that the here investigated B0 allele possesses a residual ability to convert small amounts of CBG into CBD, make it plausible that this B0 is a mutation of normally functional BD. Therefore, B0 is considered as a member of the BD allelic series encoding a CBD synthase isoform with greatly weakened substrate affinity and/or catalytic capacity.  相似文献   

9.
Application of AFLP for the detection of sex-specific markers in hemp   总被引:5,自引:0,他引:5  
H. Flachowsky    E. Schumann    W. E. Weber  A. Peil   《Plant Breeding》2001,120(4):305-309
Two dioecious hemp accessions (Can18 and Can17) were tested by bulked segregant analysis for polymorphisms between male and female bulks with amplified fragment length polymorphisms. Thirty‐nine primer combinations were tested and 20 of these yielded one to three male‐specific bands. In contrast, no female‐specific band was detected. Eight of these primer combinations were used for testing 80 progeny plants from a cross between two plants from Can18 and 30 plants from Can17. A total of 16 and 17 male‐specific fragments were obtained for Can 18 and Can 17, respectively. Eleven fragments exhibited the same fragment size in both accessions. All male plants, but not one female plant, showed the respective polymorphic band with each of the eight primer combinations. Problems regarding sex determination under field conditions were successfully overcome by testing plants that had been grown in small pots in a greenhouse. The abundant number of potential markers for the male sex, their complete cosegregation with male plants and the absence of markers for the female sex support the presence of a male sex chromosome in hemp.  相似文献   

10.
Plant development and stem yield of mono- and dioecious fibre hemp cultivars ( Cannabis sativa L.), introduced to Finland from regions of lower latitude, were studied in field experiments under long-day growth conditions in 1995–96. Plant density, plant mortality rate, stem elongation and stem yield were determined. Plant densities at seedling stage were less than the targeted viable seeds sown m−2. Seedling densities differed significantly among cultivars, but had no significant effect on plant mortality rate in 1996. Plant mortality during the 1996 growing season averaged 34 plants m−2. Stem elongation was measured at one-week intervals throughout the growing time. The elongation among cultivars was different and depended on the date of measurement. Rapid elongation began five to six weeks after sowing and elongation was most pronounced in July. Dioecious cultivars were significantly taller than monoecious ones in 1995 but not in 1996 when hemp stands were dense, nitrogen was deficient and an infection of Botrytis vinerea was present. Dioecious cultivars produced higher stem yields than monoecious ones. However, in 1996 the difference in yield was not statistically significant among most of the cultivars, Cultivar Uso 11 was early maturing and produced highest stem yield among monoecious cultivars; it also competed well with the higher yielding dioecious cultivars.  相似文献   

11.
Cold tolerance at the early growth stage in wild and cultivated rice   总被引:1,自引:0,他引:1  
The present study was conducted to understand the pattern of variation and the genetic bases for cold tolerance at the early growth stage in Asian rice. The genetic variation was investigated at the germination, plumule and seedling stages among 57 strains including cultivated rice (Oryza sativa ssp. indica and ssp. japonica) and its wild progenitor (Oryza rufipogon). The significant differentiation of cold tolerance was observed among the taxonomically divided groups. At the germination stage, both indica and japonica subspecies tended to be more tolerant than O. rufipogon, whereas at the plumule and seedling stages, ssp. japonica tended to be more tolerant than ssp. indica and O. rufipogon. Furthermore, in cold tolerance at the plumule stage, the clinal variation across the latitude of origins was observed within O. rufipogon and ssp. japonica, suggesting that the current pattern of variation seems to have been shaped by both their phylogenetic histories and on-going adaptation to the local environments. QTL analysis between O. sativa ssp. japonica (tolerant) and O. rufipogon (susceptible) revealed five putative QTLs for cold tolerance at the plumule and seedling stages but not at the germination stage. Substitution mapping was also carried out to precisely locate the two major QTLs for cold tolerance at the plumule stage, which could be used for improvement of tolerance to cold stress in ssp. indica.  相似文献   

12.
一般认为黄檗为严格的雌雄异株植物,但本研究首次发现自然界存在两性植株。为了研究两性植株的有性繁殖能力,以两性植株为试材,雌株和雄株为对照,对两性植株性器官形态和繁殖能力进行了研究。通过2年对5000余朵花的研究发现:(1)两性植株的花粉和柱头与雄株和雌株在形态和发育上没有差异,花粉的萌发率在23%以上,与雄株花粉基本一致;(2)两性植株花粉授粉至雌株后得果率为86.69%,两性植株雌花在接受雄株花粉后的得果率为91.30%,自然受粉条件下的得果率为95.69%,自交授粉的得果率为88.01%。两性植株雄性和雌性都能正常繁殖,也可以成功自交繁殖。本研究为黄檗性别分化研究提供了新方向,为其生物保护提供了新途径。  相似文献   

13.
Summary Interspecific crosses were carried out between the three Lactuca species L. virosa, L. serriola and L. sativa to transfer resistance to the leaf aphid Nasonovia ribis nigri from L. virosa to the cultivated lettuce. L. sativa, L. serriola was used as an intermediate parent between the other two species. Many irregularities were observed in the interspecific hybrids, ranging from premature dying of F1 plants resulting from a kind of bastard necrosis till complete male and female sterility and deviating microsporogenesis. Using in vitro culture and after several backcrosses male and female fertile plants were obtained with a L. sativa habit and with resistance to the leaf aphid.  相似文献   

14.
G. Mandolino  A. Carboni 《Euphytica》2004,140(1-2):107-120
Summary The development and applications of molecular markers to hemp breeding are recent, dating back only to the mid-1990s. The main achievements in this field are reviewed. The analysis of Cannabis germplasm by RAPD, AFLP and microsatellites is discussed, with its consequence for the still debated species concept in Cannabis. DNA-based markers have also been exploited in the field of forensic science, in an attempt to discriminate licit from illicit crop. The main applications of the molecular markers to the breeding, however, have been achieved with the development of markers closely linked to the male sex and to some of the most relevant chemotypes. Active research is carried out by several groups in the field of identification and characterization of the genes involved in fiber quality and quantity, and in the determination of monoecy, another very important target of hemp breeding. Besides, markers associated to new, potentially useful chemotypes are being developed, for the marker-assisted breeding of pharmaceutical Cannabis.  相似文献   

15.
Sex type determination in papaya (Carica papaya L.) is very important for crop improvement processes because it accelerates the identification of the fruitful plants. The use of molecular technology provides a quick and reliable identification of sex types in plantlets growing in seedbeds. Random amplified polymorphic DNA (RAPD) markers were used to determine the sex types of Colombian cultivars of dioecious papaya genotypes. This species has three sex types (male, female and hermaphrodite) determined by a multiallelic locus. There are no morphological differences at the chromosome level; therefore the identification of sex types by chromosomal dimorphism is not possible. A RAPD marker of 900 bp was found in male plants, but not in females or hermaphrodites. From this RAPD marker a sequence characterized amplified region (SCAR) was developed and it was possible to amplify fragments from the genomes of male and hermaphrodite plants, but not the female ones. The results indicate that this new SCAR marker will be valuable to determine the sex type of papaya plants.  相似文献   

16.
Summary Various genes for disease resistance identified in wild Lactuca are difficult, even impossible to exploit in lettuce breeding, due to sexual incompatibility between L. sativa and wild Lactuca sp. We adapted two cellular biology techniques to overcome these interspecific barriers: in vitro embryo rescue and protoplast fusion. In vitro rescue of immature embryos was used successfully for sexual hybridization between L. sativa and L. virosa. Vigorous hybrid plants were produced between L. sativa and seven accessions of L. virosa. Protoplast fusion permitted the regeneration of somatic hybrids between L. sativa and either L. tatarica or L. perennis. Hybrids between L. sativa and L. tatarica were backcrossed to L. sativa.  相似文献   

17.
Genetic diversity of Cannabis sativa germplasm based on RAPD markers   总被引:5,自引:0,他引:5  
V. Faeti    G. Mandolino  P. Ranalli 《Plant Breeding》1996,115(5):367-370
Random amplified polymorphic DN A (RAPD) markers were generated from 13 cultivars and accessions of Cannabis sativa L. Approximately 200 fragments generated by 10 primers of arbitrary sequence were used to assess the level of DNA variation. Statistical analysis was performed using the Dice coefficient of similarity and principal coordinate analysis. The grouping of the accessions according to the cluster analysis was in good agreement with their origin and lines with common ancestors were grouped together. Principal coordinates 1 and 2 revealed a clear separation of Italian and Hungarian germplasm and a third group, including a mixture of genotypes coming from different places; the third coordinate separated the Korean group which is probably the most divergent germplasm. Variability within the two cultivars ‘Carmagnola’ and ‘Fibranova1’ was also shown, suggesting good possibilities for long–term selection work. RAPD markers provide a powerful tool for the investigation of genetic variation in cultivars/accessions of hemp.  相似文献   

18.
Summary With the aim to examine its potential as a renewable resource to decontaminate polluted soils, electron microscopy combined with X-ray microanalysis was used to investigate the localization of copper in Cannabis sativa grown in hydroponic copper-rich culture. Cu was found to accumulate preferentially in the upper leaf epidermal cells; it was also detected in spiculae and in abaxial trichomes too. Primary bast fibres seem to be not involved in copper accumulation.  相似文献   

19.
Summary Hop (Humulus lupulus L.) is dioecious species with female plants of commercial value. During breeding process it is desirable to identify the sex of hop plants at the stage of seedling. Twenty two inter simple sequence repeat (ISSR) primers were screened on female and male hop genotypes of Russian and European origin. Two ISSR primers revealed fragments specific for male plants of hop. Based on the sequences two pairs of primers were designed. These male specific sequence tagged site (STS) markers were tested on male hop accessions of Russian origin and female hop accessions of Russian, European and American origin. A high homology of male specific hop DNA sequences to expressed sequences from EMBL plants EST database was found, most of which code cell wall glycoproteins. The applicability of ISSR-PCR analysis for development of sex molecular markers in hop is discussed.  相似文献   

20.
Summary Application of 200 to 800 mg/l silver nitrate (AgNO3) to the female kakrol or teasle gourd (Momordica dioica Roxb.) plant was effective for inducing hermaphrodite flowers. Pollen grain viability of the hermaphrodite flowers was as high as that of normal male flowers. Crossing among female genotypes of different fruit morphotypes, taking pollen from the induced hermaphrodite flowers, produced fruits and seeds. Sex of hybrids between female and normal male segregated into male and female in equal proportion, while the hybrids from female homo-sexual crosses produced only female plants. This indicated that sex of kakrol is controlled by a single factor; male being heterozygous and the female is homozygous recessive. The possibility to evaluate both parents for fruit characteristics should facilitate breeding.  相似文献   

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