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1.
Buffel grass (Cenchrus ciliaris L.) is an important apomictic grass used as forage for ruminant livestock. Biotechnological methods provide opportunities for producing new germplasm. Mature embryos of fourteen buffel grass apomictic cultivars (2n = 4x = 36) were used to induce embryogenic callus formation using a basal medium supplemented with 3% sucrose and with the testing of five concentrations of 2,4‐dichlorophenoxyacetic acid (2,4‐D) and four concentrations of 6‐benzylaminopurine (BAP). The effects of cultivar and culture medium on callus induction and plant regeneration were evaluated. Significant differences were observed among the fourteen cultivars and the five concentrations of 2,4‐D (P < 0·01). Values for embryogenic callus production varied from 0 to 86·7. Most cultivars showed the highest level of embryogenic callus production on the medium with the concentration of 3 mg L?1 2,4‐D. The addition of different BAP concentrations in combination with 2,4‐D in the medium inhibited embryogenic callus growth and did not permit plant regeneration. The data clearly demonstrated that the genotype and concentrations of 2,4‐D had significant effects both on the frequency of embryonic callus formation from mature embryos and on the subsequent efficiency of plant regeneration of apomictic cultivars of buffel grass. Cultivars Biloela and Nunbank showed the greatest efficiency in in vitro culture response.  相似文献   

2.
Damage produced by salt stress (300 mm NaCl) under hydroponic greenhouse conditions in seedlings of eight Buffel grass (Cenchrus ciliaris L. Syn. Pennisetum ciliare Link) genotypes was estimated through different component characters of total fresh weight damage (DTFW). Coefficient of genetic determination (CGD) was estimated for each character as well as their direct and indirect contribution to damage to total fresh weight, considered as biomass production loss. Americana and Biloela were the most salt‐tolerant cultivars, whereas sexual line and Texas 4464 were the genotypes most susceptible to salt stress. Damage to fresh weight of aerial part (DFWA) was the only component with a direct effect on DTFW and with a high CGD. Therefore, DFWA could be used in breeding programmes as an indirect selection criterion for tolerance and better productivity.  相似文献   

3.
Livestock production is the main source of livelihood in the arid and semi‐arid lands in Africa. However, desertification characterized by vegetation degradation and soil erosion is a major threat to the sustainability of land‐based production systems. Native rangeland forage species Cenchrus ciliaris L. (Buffel grass/African foxtail grass), Eragrostis superba Peyr. (Maasai love grass) and Enteropogon macrostachyus (Hochst. Ex A. Rich.) Monro ex Benth. (Bush rye grass) have been used to combat desertification. The objectives of the study were to identify the best‐suited native grass species to combat desertification in a semi‐arid environment in Kenya and to identify the preferred grass species among the agropastoralists in the area. Percentage basal cover, plant densities and frequencies of the three grasses in pure stands and mixtures were estimated. Grass species preferences were through household survey and focus group discussion. Results showed a significant difference (P < 0·05) in plant densities and cover estimates: E. macrostachyus was ranked first; C. ciliaris and E. superba were ranked second and third respectively. The agropastoral farmers, however, preferred E. superba followed by C. ciliaris and E. macrostachyus, a reverse trend. These results suggest that the choice of grass species to combat desertification is influenced more by its contribution as a source of forage for livestock than its contribution for rehabilitation purposes.  相似文献   

4.
Indigenous perennial grasses are widely distributed in the Arabian Peninsula. Their survival under limited rainfall and grazing suggests a potential role as grassland species and for rehabilitation of degraded rangelands. Forage productivity, seed production and water‐use efficiency (WUE) was determined over 2 years for four indigenous grasses: buffel grass (Cenchrus ciliaris L.), dakhna (Coelachyrum piercei Benth.), da’ay (Lasiurus scindicus Henr.) and tuman (Panicum turgidum Forssk.) together with one exotic species, rhodes grass (Chloris gayana Kunth) in the central region of the United Arab Emirates. Three irrigation treatments were used: R1 (1858–6758 m3 ha?1 year?1), R2 (929–3379 m3 ha?1 year?1) and R3 (464–1689 m3 ha?1 year?1). Buffel grass had the highest dry‐matter (DM) yield under all irrigation treatments. The average DM yield of buffel grass was 14·6 and 15·1 t ha?1 in the 2 years which was significantly higher than that for the other grasses with dakhna having the lowest DM yields. The WUE of 0·7 and 0·8 kg DM m?3 in the 2 years for buffel grass was significantly greater than for the other grasses. Buffel grass showed the highest increase in WUE in both years when the irrigation was reduced from treatment R1 to R3. The results suggest that the desert grasses of the Arabian Peninsula, such as buffel grass, could be useful grass species in reducing the use of scarce irrigation water provided that seed production can be increased.  相似文献   

5.
Buffel grass (Cenchrus ciliaris L.) is an important forage grass in arid and semiarid regions. As part of a genetic improvement programme, four genotypes [Biloela (Bl), Americana (Am), Texas (Tx) and Sexual (Sx)] were categorized by tolerance to heat stress in a greenhouse experiment. At 30 d after sowing, half of the plants (control plants) were transferred to growth chambers (28°C day per night), and the other half (pre‐treated plants, Prt) were exposed to heat stress treatment (0, 24, 48 and 72 h; 45°C day per night). Malondialdehyde (MDA) content, an indicator of oxidative damage, was determined from foliar samples. During heat stress, Sx showed the earliest increase in MDA (at 24 h) followed by Tx (48 h) and Am and Bl (72 h). Results were compared with heat‐stress tolerance evaluated as morphological traits at the end of recuperation (60 d after sowing). Fresh weight and aerial plant height were lowest in the Prt‐Sx genotype and highest in Am and Bl genotypes; Tx showed intermediate tolerance. Results suggest that tolerance to heat stress in C. ciliaris genotypes could be related to the capacity for regulating the oxidative damage increase. Foliar MDA content might therefore be used in a genetic improvement programme of C. ciliaris as a potential biochemical indicator for a rapid, simple and low‐cost identification of heat‐stress tolerant genotypes.  相似文献   

6.
The field performance of the native Pappophorum vaginatum, the naturalized Eragrostis curvula and various cultivars of the introduced Achnatherum hymenoides and Leymus cinereus was evaluated as potential forage resources in rangelands of arid Argentina during the warm seasons of 2007/2008 and 2008/2009. Plants of these grass species, obtained from seeds, were transplanted to the field in 2006, when they were 1 year old. During the study years, there were two defoliation managements: plants of all study genotypes either remained undefoliated (controls) or were defoliated twice a year during spring at 5 cm stubble height. Despite tiller number being lower (P < 0·05) on defoliated than on undefoliated plants, and total leaf length per unit basal area being similar (P > 0·05) between defoliation managements by mid‐spring, there were no differences (P > 0·05) in dry weight production between defoliated and undefoliated plants in all genotypes at the end of the second growing season. Plants of one or more of the introduced genotypes showed a similar (P > 0·05) or greater (P < 0·05), but not lower, tiller number per plant and per square centimetre, daughter tiller production, total leaf length and dry weight production per unit basal area than the native species at the end of the first and/or second growing seasons. These morphological variables were similar (P > 0·05) or greater (P < 0·05) in the native than in the naturalized genotype. Plant survival, however, was lower (P < 0·05, overall mean = 20%) in the introduced than in the native (>70%) or naturalized (>39%) genotypes at the end of the first or second growing seasons.  相似文献   

7.
普通小麦F1代籽粒高分子量谷蛋白亚基的遗传表现   总被引：1，自引：0，他引：1       下载免费PDF全文
为给小麦品质改良提供依据，采用SDS-PAGE方法,以来自国内外的6个小麦品种（系）为材料，分析了15个杂交组合F1代高分子量谷蛋白亚基（HMW-GS）的遗传表现。结果表明：①HMW-GS在F1代的遗传具有剂量效应，即部分正反交组合F1代籽粒中同一亚基带的颜色深浅不同，来自母本的亚基带比来自父本的亚基带颜色深,说明来自母本的亚基比来自父本的亚基含量高;②2个国内与国内品种间的杂交组合及2个国外与国外品种间的杂交组合，其F1代HMW-GS均表现为完全共显性，11个国内和国外品种间的杂交组合，有4个组合的F1代出现了HMW-GS的不完全表达，缺失率占11个组合总数的36％。  相似文献   

8.
  为了解水稻耐低锌能力基因型差异的生理机制及F1杂种的耐低锌能力以提高水稻锌效率,解决水稻锌缺乏问题,选用耐低锌基因型水稻IR8192、IR36,锌敏感基因型水稻Ce 64、IR26及杂交后代IR36×IR8192、IR36×IR26和Ce 64×IR26为材料,进行低锌(pZn2+ 11.0)和正常锌(pZn2+ 9.7)营养液培养。结果表明：1)亲本和F1幼苗的株高,叶鞘高,地上部和地下部干质量及锌含量,叶片的叶绿素含量、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性、丙二醛(MDA)含量在pZn2+ 11.0与pZn2+ 9.7条件下的相对值可作为耐低锌基因型水稻的筛选指标;2)在低锌条件下所有亲本及F1各项指标变化趋势相同,但IR8192、IR36、IR36×IR8192、IR36×IR26的叶绿素含量、SOD酶活性降幅较小,POD、CAT、APX活性升幅较大,MDA含量升幅较小,表明上述基因型水稻的耐低锌能力更强。 低锌胁迫下POD、CAT、APX活性增强,可以更有效地清除活性氧,SOD活性则最先下降;3)除根长、APX活性外,在低锌条件下,IR36×IR8192、IR36×IR26各项指标变化幅度均表现出超亲优势,而Ce 64×IR26则表现出偏中亲优势,推测水稻的耐低锌特性主要受基因的显性效应控制,并存在基因的叠加效应,可以通过耐低锌亲本间的杂交获得具有更强耐低锌能力的水稻基因型。  相似文献   

9.
The effect of defoliation interval on growth patterns of contrasting perennial ryegrass (Lolium perenne)–white clover (Trifolium repens) mixtures was studied. The dynamics of increase in leaf area, light interception and dry-matter (DM) production were measured within successive regrowth periods. No N fertilizer was applied. During 1995 six mixtures were cut eight (F1) or six times (F2) at a stubble height of 5 cm. The stubble composition was stable throughout the growing season: after harvest about 50 g DM m?2 (with a white clover proportion of 0·52) was present with a leaf area index (LAI) of 0·5 (0·38 white clover). The percentage of intercepted radiation after cutting was 20–30% and increased during 3 weeks to about 95%. The relative growth rate of leaf area and DM was higher for white clover than for perennial ryegrass, with the proportion of clover in the LAI and DM increasing during each regrowth period. Mixtures with large-leaved white clover cv. Alice had a lower initial clover content after harvest, but a more rapid increase in clover LAI and DM than mixtures with the smaller leaved cvs Gwenda or Retor. Alice had the highest total and clover LAI and DM at harvest. Cutting frequency affected the change in white clover–perennial ryegrass ratio during regrowth. This was significantly higher in mixtures with Alice than in mixtures with Gwenda, but only under less frequent cutting (F2). In spring there was a mean white clover proportion of about 0·55 in the LAI and 0·45 in the total harvested DM. In summer the white clover proportion in the LAI and DM increased to 0·70–0·75. There was a decline during autumn, especially in F2 and in the mixtures with the small-leaved white clover cv. Gwenda and the medium-leaved cv. Retor. In contrast, grass DM and LAI declined from spring to summer. The decline in clover LAI in autumn was similar in Alice and Gwenda at frequent cutting (F1), but stronger in Gwenda in F2. Retor had the lowest clover specific leaf area (SLA). The SLA values of Alice and Gwenda were similar, SLA being similar between cutting treatments. No differences were found for leaf weight ratio (LWR) among the three white clover cultivars or between the grass cultivars, and LWR was not affected by cutting treatment. Defoliation interval had limited effects on the growth pattern and leaf characteristics of perennial ryegrass–white clover mixtures.  相似文献   

10.
本研究对大豆病毒病抗性不同的大豆杂交亲本及F_1代,接种SMV_1号株系后的过氧化物酶和酯酶同工酶的变化进行了分析。结果表明,抗病与感病亲本及其F_1代接种后的同工酶谱带存在着明显的差异。感病亲本及F_1代酶的活性增强,酶带数较多,而且部分酶带变宽,颜色变深。抗病亲本则不发生变化。各组合F_1代的酶谱与双亲有关,抗病×抗病的F_1代酶谱与双亲完全相同,抗病×感病的F_1代酶谱偏向抗性亲本,感病×感病的F_1代产生一个双亲所不具备的小分子新杂种酶带。未接种的感病亲本酶谱与抗病亲本相同。植株内部同工酶的变化与成株抗性相一致。因此,我们认为过氧化物酶同工酶,可作为鉴定大豆抗感病毒病的生化指标之一。  相似文献   

11.
Amplified fragment length polymorphism (AFLP) markers were used to distinguish commercial cultivars and to assess the level of polymorphism in potato. AFLP analysis templates were made using Eco RI and Mse I as described in the Gibco BRL AFLP kit protocol. Seven primer combinations with three selective nucleotides on both primers were screened individually with 12 potato cultivars. Multiple polymorphisms could be detected in a single reaction to the extent that all 12 commercial potatoes tested could be distinguished using any one primer combination. Up to 84 polymorphic bands were detected with a single primer combination among 12 accessions. The seven primer combinations generated a total of 466 bands, of which 409 (88%) were clearly polymorphic among the cultivars. The presence or absence of each AFLP markers was scored and then phylogenetic and genetic distance analyses were used to generate dendrograms showing genetic relationships among the cultivars evaluated. The analyses based on amplified DNA fragments did not always reflect the known genetic relationships among the cultivars. These results demonstrate that AFLP DNA markers can be of great value in identification and measurement of variation, but should be treated with caution for purposes of estimating true measures of genetic similarity in potato.  相似文献   

12.
由于缺乏传统遗传标记，花生遗传连锁的报道极为罕见，迄今未发表经典的遗传图谱。发展稳定可靠的AFLP标记，将为基因分型应用于新品种保护、良种保纯、杂种鉴定和种质资源研究提供强有力的技术支撑。研究在建立适合花生AFLP分析的DNA提取流程的基础上，建立了花生AFLP分析的技术方案。AFLP分析结果表明，6个花生杂交亲本间存在一定差异。四对引物共计扩增出307条长度不同的条带。其中多态性条带为160条，占总条带数的52．1％。本研究筛选获得了多态性程度高的杂交亲本，为进一步构建分子连锁图谱创造了条件。  相似文献   

13.
The diallel cross constitutes an informative genetic design for choosing genitors and crosses in breeding programmes since it provides estimates of general (GCA) and specific (SCA) combining abilities. Because the breeding programme for Urochloa humidicola ([Rendle] Morrone & Zuloaga; syn. Brachiaria humidicola [Rendle] Schweick) at Embrapa Beef Cattle is recent, these estimates are still unknown. Thus, the aim of this study was to obtain the estimates of GCA and SCA from the partial diallel cross design between sexual and apomictic parents. The crosses involved nine sexual and ten apomictic parents. Seventy‐one full‐sib progenies were obtained and evaluated in an incomplete block design, using all parents and the cv. BRS Tupi as a check. The agronomic and forage quality traits were evaluated using seven harvests. Statistical analysis was performed using the mixed model approach. Significant variations were associated with GCA among sexual parents for biomass yield and forage quality traits. However, this cannot be observed for apomictic parents for GCA. The SCA effect was not significant for the assessed traits. These results showed the predominance of additive effects. Sexual parents SEX3 and SEX4 presented the highest potential for contributing favourable alleles in hybrid combinations. The absence of GCA among apomictic parents and SCA suggests the need to increase genetic variability for the generation of breeding populations of U. humidicola.  相似文献   

14.
两系杂交稻籽粒充实度亲子相关研究   总被引：2，自引：0，他引：2  
选用８个籼型光温敏不育系作母本，１０个粳型广亲和品种和６个灿稻材料作父本，共配制灿粳亚种间杂交组合４０个，品种间杂交组合１９个，对杂种Ｆ１与双亲的籽粒充实度进行了相关分析，结果表明：两系亚种间杂种Ｆ１籽粒充实度与其父本、母本籽粒充实度及双亲平均籽粒充实度亦呈显著或极显著正相关，说明要提高两系杂交稻籽粒充实度，选用充度好的亲本配组很重要，对解决两系灿粳亚种间杂交稻籽粒充实不良的途径也进行了讨论。  相似文献   

15.
Jatropha curcas (Euphorbiaceae), a drought resistant non edible oil yielding plant, has acquired significant importance as an alternative renewable energy source. Low and inconsistent yields found in field plantations prompted for identification of high yielding clones and their large scale multiplication by vegetative propagation to obtain true to type plants. In the current investigation plantlets of J. curcas generated by axillary bud proliferation (micropropagation) using nodal segments obtained from selected high yielding genotypes were assessed for their genetic stability using Randomly Amplified Polymorphic DNA (RAPD) and Amplified Fragment Length Polymorphism (AFLP) analyses. For RAPD analysis, 21 out of 52 arbitrary decamer primers screened gave clear reproducible bands. In the micropropagated plantlets obtained from the 2nd sub-culture, 4 out of a total of 177 bands scored were polymorphic, but in the 8th and 16th sub-cultures (culture cycle) no polymorphisms were detected. AFLP analysis revealed 0.63%, 0% and 0% polymorphism in the 2nd, 8th and 16th generations, respectively. When different genotypes, viz. IC 56557 16, IC 56557 34 and IC 56557 13, were assessed by AFLP, 0%, 0.31% and 0.47% polymorphisms were found, respectively, indicating a difference in genetic stability among the different genotypes. To the best of our knowledge this is the first report on assessment of genetic stability of micropropagated plantlets in J. curcas and suggests that axillary shoot proliferation can safely be used as an efficient micropropagation method for mass propagation of J. curcas.  相似文献   

16.
利用AFLP分子标记对云南紫稻细胞质无花粉水稻三系及杂种F1进行了指纹图谱的构建与比较分析。从14对引物中筛选出8对具有明显多态性的引物。天香018（天香A×珞恢018)材料组（不育系、保持系、恢复系及杂种F1）共扩增出179条带,其中有52条多态性谱带,占总带数的29.05％,平均每对引物可以扩增出6.50条多态性谱带;天香806(天香A×珞恢806)材料组(不育系、保持系、恢复系及杂种F1）共扩增出177条带,其中有50条差异带,占总带数的28.25％,平均每对引物可以扩增出6.25条多态性谱带。特别明显的是在引物对E ATG/M CAC的扩增中,在AFLP指纹图谱中出现两条特征带（a带和b带）,为保持系所特有,能够明显区别于不育系、恢复系和F1。在另外一些引物对中也观察到不育系与保持系之间的差异带。  相似文献   

17.
选用400个随机寡核苷酸和40个荧光标记的微卫星引物对,对我国主栽的协优杂交稻组合及其亲本进行多态性分析。RAPD分析显示,400个随机寡核苷酸引物中,有364个能够在供试基因型材料中扩增出肉眼可见的DNA条带,其中28个显示扩增的多态性,这中间9个引物产生的13条多态性条带具有清晰、易分辨的特点,可以在供试的水稻组合与亲本之间,以及杂交组合之间进行区别和鉴定。微卫星分析指出,40对荧光标记引物中,13对引物产生的31条标记带,能够在供试基因型材料中显示稳定的多态性,且杂种表现为双亲的互补型。与RAPD相比,微卫星分析具有多态性强、精确性高和重复性好的特点。  相似文献   

18.
Hybridization in the Urochloa humidicola breeding programme allowed to explore the genetic variability of the apomictic sources and, thus, to obtain new sexual and apomictic parents with compatible ploidy and/or superior progenies. However, given the high variability arising from crosses, there is a need to adopt efficient selection strategies among and within progenies. The aim of this study was to compare the selection methods among U. humidicola progenies with (t-BLUP) and without (BLUP) the weighting based on prediction error and subsequent selection within progenies by individual simulated (BLUPIS) or optimal individual BLUP. We evaluated seventy-one U. humidicola full-sib progenies from biparental crosses between nine sexual and ten apomictic parents. The experiment was set up in an incomplete block design with 64 blocks of 15 plots each, consisting of individual plants. Seven consecutive cuts were made and the traits total dry-matter, leaf dry-matter and regrowth scores were measured. Genetic variance was expressive for all traits. The selection procedure among progenies of U. humidicula based on t-BLUP proved to be more advantageous regarding the use of BLUP not weighted by the prediction error, resulting in higher selection gains, taking as reference the optimal procedure of the individual BLUP. Furthermore, the use of BLUPIS allowed an optimized selection of hybrids, allowing the breeder to explore with variable selection intensity the genetic variability within the selected full-sib progenies based on relative genetic merit.  相似文献   

19.
Bioethanol production from sweet sorghum entails expansion and intensive production of the crop, which may include off-season production in the warm tropical lowlands. However, suitable cultivars are currently not available for this environment, especially in southern Africa. Hybrid cultivars were long ago demonstrated to be more productive than pure line varieties. Therefore a study was conducted to determine heterosis of experimental hybrids, and combining ability of parental lines for stem sugar traits. Sixty-four hybrids were generated among 16 lines in accordance with North Carolina design II mating scheme. Eight parents were cytoplasmic male sterile lines which were designated as females and were crossed with eight male fertile lines. The hybrids were evaluated at two sites in Mozambique and South Africa under off-season production conditions. Row-column alpha designs with three replications were used and standard agronomic practices were followed at both sites. Data were analysed in GenStat computer package. There was significant (P = 0.05) variation among genotypes for stem °brix and associated traits. The top 20 stem °brix performers were constituted by 17 hybrids, exhibiting heterosis of up to 112%, and three parents. General and specific combining ability effects were significant for stem °brix and associated traits implying that both additive and non-additive gene action, respectively, were important for controlling the traits. The lines ZLR1 and ICSVP3046 displayed significant and positive GCA effects for stem °brix, while 13 crosses showed positive and significant SCA effects. These lines and the crosses ISCVP3046 × ICSA4, ICSV700 × ICSA731, ICSR165 × ICSA307, ZLR1 × ICSA474 and ICSR57 × ICSA479, which combined high mean performance with positive SCA effects, would be recommended for use in breeding new varieties for tropical lowland environments.  相似文献   

20.
利用DNA指纹鉴定玉米杂交种纯度及其真伪技术的研究   总被引：24，自引：2，他引：22  
从500个随机引物中筛选出30个在玉米上具有较好多态性的RAPD随机引物,并进一步筛选确定了适合我国主要玉米杂交种及其双亲的特异引物,建立了相应的DNA指纹图谱。杂交种的DNA指纹图谱表现为父、母本双亲带型的互补,均未出现互补带型之外的新带型。应用RAPD技术获得DNA指纹图谱的方法可以简便、快捷、经济、准确地鉴别玉米杂交种子纯度及真伪。目前已进行了上百份的检测实践,无一差错。  相似文献   

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