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1.
Multivariate methods, including principal component, cluster and discriminant analyses, were used to assess the patterns of morphological variation and to group 415 sorghum accessions for 15 quantitative characters. The first five principal components explained 79% of the total variation with plant height and days to 50% flowering being the most important characters in the first principal component. Cluster analysis grouped the accessions into ten clusters. A greater proportion of accessions of similar adaptation zones and accessions from regions of origin with similar agro-climatic conditions were grouped together. Moreover, discrimination of accessions was more pronounced when discriminant analysis was based on zone of adaptation rather than regions of origin. Based on the observed patterns of variation, it is concluded that the morphological variation in the material studied is structured by environmental factors. The implications of the results for plant breeding and germplasm conservation programmes arediscussed. 相似文献
2.
The Ethiopian region is characterised by a wide range of agro-climatic conditions, which accounted for the enormous resources
of agro-biodiversity that exist in the country. The most important of these resources is the immense genetic diversity of
the various crop plants in the country. Of these, one of the most on farm genetically diverse crops is sorghum. Since the
advent of formal breeding in particular after green revolution, genetic diversity of most crops has been threatened worldwide.
In order to assess on farm genetic erosion (GE), various research methodologies were employed. These were focused group interviews
with 360 farmers, on farm monitoring and participation with 120 farmers, key informant interviews with 60 farmers and development
agents, and semi-structured interviews with 250 farmers. Besides, diversity fairs were done with over 1200 farmers. Notwithstanding
the complexity of assessing GE, it was assessed by various methods; namely, by temporal method (comparing 1960 and 2000 collections),
area method, and semi-structured interview method at individual, community or wereda level and causes of varietal loss from other various perspectives. Farmers perceived GE as the reduced importance of the
variety as indicated by lower proportion in the varietal portfolio. The five most important factors for varietal loss at individual
farmers’ level were reduced benefit from the varieties, drought, Khat expansion, reduced land size and introduction of other food crops respectively. GE was not affected by wealth groups and
ecological regions. Farmers do not make simple replacement as a strategic mechanism for genetic resources management. GE at
regional level was quantified by temporal and spatial method. There was a complementation not rivalry between farmer varieties
(FVs) and improved varieties (IVs). The whole process of GE is explained by three models, namely: Bioecogeographic enhanced
genetic erosion model, Farmer induced genetic erosion model and Farmer-cum-bioecogeographic genetic erosion model. As aforementioned,
sorghum genetic erosion behaviour is completely different from other food crops such as tetraploid wheat. The prediction in
the late seventies that complete erosion of FVs by IVs by the end of the eighties, the principle of GE that competition between
IVs and FVs, favours the former and results in the replacement of the latter is not valid in the context of sorghum in Ethiopia.
Hence, maintenance of the on farm genetic diversity of sorghum is a reality but GE is rhetoric. 相似文献
4.
Genetic and phenotypic diversity among randomly selected 36 downy-mildew-resistant sorghum accessions were assessed, the former using 10 simple sequence repeat (SSR) marker loci and the latter using 20 phenotypic traits. The number of alleles ( a
j
) at individual loci varied from five to 14 with an average of 8.8 alleles per locus. Nei's gene diversity ( H
j
) varied from 0.59 to 0.92 with an average of 0.81 per locus. High gene diversity and allelic richness were observed in races durra caudatum ( H
j
= 0.76, a
j
= 4.3) and guinea caudatum ( H
j
= 0.76, a
j
= 3.8) and in east Africa ( H
j
= 0.78, a
j
= 7.2). The regions were genetically more differentiated than the races as indicated by Wright's F
st. The pattern of SSR-based clustering of accessions was more in accordance with their geographic proximity than with their racial likeness. This clustering pattern matched little with that obtained from phenotypic traits. The inter-accession genetic distance varied from 0.30 to 1.00 with an average of 0.78. Inter-accession phenotypic distance varied from 0.01 to 0.55 with an average of 0.33. Eleven accession-pairs had phenotypic distance of more than 0.50 and genetic distance of more than 0.70. These could be used as potential parents in a sorghum downy mildew resistance-breeding program. 相似文献
5.
The purpose of this study was to analyze the effects of silicon (Si) nutrition on sorghum growth under drought. The present study investigated the distribution of Si in plant parts under stress conditions and its effects on physiological and growth traits. The study was conducted during 2 years (2007–2009) at PMAS Arid Agriculture University, Rawalpindi, Pakistan. Polyethylene glycol (PEG) 6000 (–4.0, –6.0, –8.0, and –10.0 Mpa) solution was used to screen drought-tolerant (Johar1) and drought-susceptible (SPV462) sorghum ( Sorghum bicolor L.) cultivars, which were replicated three times with Si sources of potassium silicate (K 2SiO 3) (Si 300: 300 ml L ?1) and control (Si 0) treatments. The results showed that drought-tolerant cultivars accumulated maximum Si under Si treatment versus Si absence, which resulted increased leaf water potential, leaf area index, Soil Plant Analysis Development (SPAD) chlorophyll, net assimilation, and relative growth rate over SPV462. Similarly, Si accumulation in leaves conserved transpiration and leaf water potential, verifying Si nutrition as a defense for plants under drought. 相似文献
6.
Rare earth elements (REE) of mine tailings have caused various ecological and environmental problems. Revegetation is one of the most cost-effective ways to overcome these problems, but it is difficult for plants to survive in polluted tailings. Arbuscular mycorrhizal fungi (AMF) can provide biotic and abiotic stress tolerance to its host plant and has widely adopted for the revegetation of degraded ecosystems. However, little is known about whether AMF plays role in facilitating the revegetation of REE of mine tailings. The objective was to investigate the uptake of nutrients and REE when plants are inoculated with AMF. A greenhouse pot experiment was conducted on the effects of Glomus mosseae and Glomus versiforme for the growth, nutritional status, and uptake of REE and heavy metals by maize ( Zea mays L.) or sorghum ( Sorghum bicolor L. Moench) grown in REE of mine tailings. The results indicated that symbiotic associations were successfully established between AMF and the two plant species. G. versiforme was more effective than G. mosseae at promoting plant growth by significantly increasing the uptake of nitrogen (N), phosphorus (P), and potassium (K) and decreasing carbon:nitrogen:phosphorus (C:N:P) stoichiometry. The shoot and root dry weights of the two plant species were increased by 211–387% with G. versiforme inoculation. Maize and sorghum exhibited significant differences in the REE concentrations in response to the colonization by AMF. The shoot and root lanthanum (La), cerium (Ce), praseodymium (Pr), and neodymium (Nd) concentrations of the maize inoculated with G. versiforme were decreased by approximately 70%, whereas those in the roots of sorghum were increased by approximately 70%. G. mosseae only significantly decreased the La, Ce, Pr, and Nd concentrations in the maize shoots. Inoculation with AMF also significantly decreased the concentration of certain heavy metals in the shoots and roots of maize and sorghum. These findings indicate that AMF can alleviate the effects of REE and heavy metal toxicity on plants and enhance the ability of plants to adapt to the composite adversity of REE in mine tailings. 相似文献
7.
The extent and patterns of distribution of genetic variation among 80 sorghum ( Sorghum bicolor (L.) Moench) germplasm accessions from Ethiopia and Eritrea were investigated using RAPD with 20 oligonucleotide primers. The primers generated a total of 147 polymorphic bands across the 80 accessions with a mean of 7.35 bands per primer. Estimation of the extent of variation by the Shannon-Weaver diversity index revealed an intermediate level of overall variation ( H = 53), although the levels varied among regions of origin of the accessions. Partitioning of the total variation revealed considerable variation (77%) within the region of origin of the accessions and the remainder (23%) among regions of origin. Similarly, a large portion (94%) of the total variation was found within the adaptation zones compared to among the adaptation zones (6%). The results suggest a weak differentiation of the sorghum material both on regional and agro-ecological bases, which could be ascribed to the high rate of outcrossing in cultivated sorghum and its free natural hybridization with its wild and weedy relatives, as well as to seed movement by humans. The average genetic dissimilarity was found to be 36% among the 80 accessions and 13% among the 15 regions of origin. Cluster analysis failed to group accessions of the same region or the same adaptation zone, which further confirmed the weak differentiation of the material studied. The clustering pattern of the regions of origin was broadly concordant with previous clustering patterns obtained using morphological characters, in which regions with broad agro-climatic conditions were grouped together. 相似文献
8.
ABSTRACTWheat genotypes with pre- and post-anthesis drought tolerance offer enhanced yield gains under water-limited environments. This study determined pre- and post-anthesis drought responses of selected bread wheat genotypes in order to identify and select candidate genotypes for breeding. Fifteen genetically differentiated wheat genotypes were evaluated under non-stressed (NS), pre-anthesis drought stress (PrADS) and post-anthesis drought stress (PoADS) in glasshouse (GH) and field (FLD) environments. Data were collected on agronomic and physiological traits including number of days to heading (DTH), days to maturity (DTM), plant height (PH), number of spikelet per spike (NSPS), number of kernels per spike (NKPS), thousand kernel weight (TKW), grain yield (GY) and canopy temperature (CT). Analysis of variance revealed significant effects of genotypes, environments and their interactions for studied traits. Weak and positive correlations were recorded between GY with PH ( r?=?0.47 and 0.32), NSPS ( r?=?0.37 and 0.52) and TKW ( r?=?0.30 and r?=?0.20) under PrADS and PoADS conditions, respectively. Genotypes SMY-006, SMY-008, SMY-016, SMY-042 and SMY-044 were identified with pre- and post-anthesis drought tolerance and high yield potential and suitable yield-component traits. These are useful genetic stocks for breeding or cultivation in water-limited environments to improve yield gains. 相似文献
9.
ABSTRACTThe accident at Fukushima 1 Nuclear Power Plant in 2011 caused contamination by radioactive cesium ( 134Cs and 137Cs) in surrounding areas. After this accident, concerns about Cs contamination, including food safety, have limited industrial activities and reconstruction in Fukushima. Sorghum ( Sorghum bicolor (L.) Moench) is an annual C 4 crop that can be used as biofuel feedstock due to its high biomass. Use of Cs-contaminated fields to produce biofuel feedstock would be more acceptable than use for food or feed crops due to the lower risk of human internal exposure to radioactive Cs. In addition, high-biomass sorghum might be suitable for removal of Cs from fields (phytoremediation). For both applications, it is important to use accessions showing the appropriate level of accumulation of radioactive Cs (low for biofuel feedstock, high for phytoremediation). Here, we examined the accumulation of radioactive Cs in the aerial parts of 56 sorghum accessions grown in Fukushima. Accessions were cultivated in a low-level-contaminated field in 2011 and in a highly contaminated field in a planned evacuation zone in 2012. After cultivation, activity concentrations from 134Cs and 137Cs were measured in the aerial plant parts. In 2011, the activity concentrations of 134Cs and 137Cs were 58.2–350 and 58.6–450 Bq kg ?1 dry weight, respectively. In 2012, the concentrations of 134Cs and 137Cs were 54.2–1320 and 57.1–1960 Bq kg ?1 dry weight, respectively. Relative to the median values of the accessions grown each year, 3 showed lower activity concentrations and 2 showed higher activity concentrations of radioactive Cs under both cultivation conditions. In contrast to a previous report, there was no significant correlation between biomass and Cs activity concentration. Because both biomass and Cs concentration are important in classifying accessions for use in phytoremediation, we also calculated the Cs accumulation index (single-plant biomass × Cs activity concentration) for each accession. The accession AKLMOI WHITE showed the highest values in both years, suggesting that this accession has the high per-plant accumulation capacity for radioactive Cs. Our data collected from actual contaminated fields is irreplaceable for choosing sorghum accessions for cultivation in Cs-polluted sites such as Fukushima. 相似文献
10.
Genetic Resources and Crop Evolution - Sorghum [Sorghum bicolor (L.) Moench] is a subsistence crop and the main food for populations in arid or semiarid regions and it is appreciated for the... 相似文献
11.
Genetic Resources and Crop Evolution - Forage sorghum (Sorghum bicolor (L.) Moench) is a C4 cereal crop with excellent quality, which is widely cultivated in many countries and regions. Acid... 相似文献
12.
ABSTRACT Drought is a major factor threatening crop production worldwide. Developing wheat varieties that are adapted to drought prone environments is a sustainable strategy to improve wheat production and productivity. The aim of this study was to evaluate and select bread wheat genotypes for yield and yield components, and for stability under drought stress and non-stress conditions. One hundred and twenty genotypes were evaluated at five test sites in the 2018/19 cropping season using a 10 x 12 alpha lattice design with two replicates. The level of drought stress was imposed using different sowing dates (early planting representing non-stressed, while late planting as drought stressed conditions) following the onset of the main rain at each site. Grain yield and yield components were recorded, and drought indices were calculated for each genotype. Among the drought tolerance indices, GMP, MP, HM, STI and YI were found to be the most suitable for predicting drought tolerance because they had significant and positive correlations with yield under drought stress and non-stress conditions. Rank sum analysis identified the most drought tolerant genotypes as ‘YS-34', ‘YS-85' and ‘YS-82’. The selected wheat genotypes are useful genetic resources for future drought tolerance breeding programmes in Ethiopia or similar agro-ecologies. 相似文献
13.
Genetic variation within and among several Sorghum populations from different agroecological zones in Malawi were investigated using random amplified polymorphic markers (RAPDs). DNA samples from individual plants were analyzed using 35 oligonucleotides of random sequence. Twenty five of these primers allowed amplifications of random polymorphic (RAPD) loci. Overall, 52% of the scored loci were polymorphic. Every accession was genetically distinct. The analysis of molecular variance revealed that the within-region (among accessions) variations accounted for 96.43% of the total molecular variance. Observed variations in allelic frequency was not related to agroecological differences. The degree of band sharing was used to evaluate genetic distance between accessions and to construct a phylogenetic tree. Further analysis revealed that the sorghum accessions analyzed were genetically close despite considerable phenotypic diversity within and among them. It is suggested that all the sorghum landraces currently available in Malawi should be conserved both ex situ and in situ to maintain the current level of genetic diversity. 相似文献
14.
Abstract Understanding the responses of sweet sorghum to flooding and the characters associated with flooding tolerance may be a useful strategy for pre-rice production and help meet demand for biofuel feedstock. Three sweet sorghum genotypes (Bailey, Keller and Wray) and five flooding treatments including non-flooding control, continuous flooding extended from 30, 45, 60 and 75 days after emergence to harvest were conducted under greenhouse conditions. Flooding decreased leaf dry weight (22–60%), leaf area (10–70%), number of node per stalk (1–5%), shoot dry weight (5–20%) and stalk yield (2–22%) with highest reduction in 30 days after emergence flooding treatment. Flooding later than 30 days after emergence did not significantly affect shoot growth, yield and yield components. Brix value, sucrose content and total sugar content were not significantly affected. All studied cultivars had similar shoot growth response. Flooding induced development of roots in water; root length, root dry weight, nodal root and lateral root number and interconnection of aerenchyma spaces from roots in flooded soil to stalk base above water level but suppressed root growth in flooded soil. The acclimation traits were highest in Keller, flooding from 30 days after emergence but there was a lack of root development in 75 days after emergence flooding treatments. These findings indicate the effect of waterlogging on sweet sorghum growth and yield strongly depends on the growth stage at which it occurs. There were genetic variations in root morphological and anatomical responses to flooding of sweet sorghum. The development of nodal and lateral roots and aerenchyma formation from flooded plant parts to stalk bases above water level may distribute to flooding tolerance in sweet sorghum. Based on the results, a flood-free period of at least 30 days after emergence is required to sustain yield of pre-rice sweet sorghum and early planting is highly recommended. 相似文献
15.
ABSTRACTThe selection response of wheat ( Triticum aestivum L.) under water-limited condition can be enhanced through breeding novel genotypes possessing drought-adaptive and yield-related agronomic and physiological traits. The objective of this study was to evaluate terminal drought tolerance among bread wheat genotypes and select superior parents for breeding. Agronomic and physiological responses of 28 wheat lines were assessed under well-watered (WW) and terminal drought (TD) treatments using a 7?×?4 alpha-lattice design under rainout shelter (RS) and glasshouse (GH) environments. Significant ( p?≤?0.05) genotype?×?environment interaction effects were observed for number of days to heading (DTH), number of days to maturity (DTM), number of productive tillers per plant (TN), grain yield (GY), thousand kernel weight (TKW), stomatal conductance (SC), leaf canopy temperature (LCT) and chlorophyll content index (CCI) suggesting varied genotypic response under WW and TD treatments. Correlation analysis revealed significant associations TN and GY ( r?=?0.67; p?≤?0.001), TKW and GY ( r?=?0.72; p?≤?0.001), CCI and GY ( r?=?0.39; p?≤?0.05) under TD treatment. Drought tolerant wheat genotypes such as LM100, LM72, LM22 and LM95 are useful for direct cultivation and for developing breeding populations with enhanced yield performance. 相似文献
16.
Proteolysis during cereal germination is vital both to seedling growth and the success of commercial malting and brewing. In this study, proteinases in proteolytic extracts from seeds and germinated grains of 11 Botswana sorghum cultivars were analyzed and partially characterized by one‐dimensional electrophoresis on SDS‐PAGE gels containing incorporated gelatin. Proteinase polymorphism was detected in both germinated and ungerminated sorghum grains. Fifteen distinct proteinase bands, with Mr values of 27,000–100,000 were detected in sorghum malt extract, while ungerminated sorghum displayed a maximum of four bands ( Mr ≈ 78,000–100,000). Band numbers and identity varied markedly according to cultivar. More proteinase bands were detected at pH 4.6, than at pH 6.2 and 7.0, suggesting pH optima considerably below neutrality. Cysteine‐proteinases constituted a higher proportion (9 of 15) of the detected sorghum malt proteinases and were most detectable at pH 4.6. Multiple representatives were also detected for both serine‐ and metallo‐proteinases, although these were more active at pH 6.2 and 7.0. 1‐10 Phenanthroline inhibited malt metallo‐proteinase more strongly than EDTA, suggesting that these enzymes were most probably zinc‐dependent. Aspartyl‐proteinases were not detected, probably because of the substrate employed. Results indicate that the sorghum proteinase system is complex. 相似文献
17.
Changes in the diversity of landraces in centres of diversity of cultivated plants need to be assessed in order to monitor
and conserve agrobioversity—a key-element of sustainable agriculture. This notably applies in tropical areas where factors
such as increased populations, climate change and shifts in cropping systems are hypothesized to cause varietal erosion. To
assess varietal erosion of staple crops in a country subjected to various anthropogenic and natural environmental changes,
we carried out a study based on a comparison of the diversity of pearl millet and sorghum varieties collected in 79 villages
spanning the entire cereal-growing zone of Niger over a 26 year period (1976–2003). For these two crops, the number, name
and type of varieties according to important traits for farmers were considered at different spatial scales (country, region,
village) at the two collection dates. The results confirmed the high diversity of millet and sorghum varieties in Niger. No
erosion of varietal diversity was noted on a national scale during the period covered. Some changes were observed but were
limited to the geographical distribution of certain varieties. This highlights that farmers’ management can preserve the diversity
of millet and sorghum varieties in Niger despite recurrent and severe drought periods and major social changes. It also indicates
that rainfed cereal cropping systems in Niger should remain to be based on millet and sorghum, while reinforcing farmers’
seed systems. 相似文献
18.
The effects of aluminum on the uptake and translocation of N in two hybrid cultivars of sorghum with differential tolerance to aluminum were studied. Aluminum decreased the amount of N accumulated and the % of N in the aerial parts of the plants. In the roots the amount of N accumulated also decreased but the % of N increased, in both cultivars. Besides an effect on dry matter yield, Al probably reduces the uptake of N and its translocation to the aerial parts of the plant. Apparently, this impairment on N translocation resulted from Al effects on the root pressure. Aluminum not only reduced the amount of N translocated but also changed the sap composition. The % of NO3 ‐N decreased while the % of amino acid‐N increased suggesting an Al effect on N uptake and also on protein degradation. Asparagine and glutamine contributed about 80% of the free amino acid fraction; however, their proportions changed in presence of Al. Therefore, Al also interfered with the synthesis and/or interconversion of these amino acids. 相似文献
19.
An improved method for separating and characterizing maize (Zea mays L.) and sorghum (Sorghum bicolor L. Moench) storage proteins by free zone capillary electrophoresis (FZCE) was developed. Previous electrophoretic methods for analyzing these proteins required high concentrations of urea to maintain protein solubility during separation. To overcome disadvantages of urea, we developed a FZCE method that mimicked reversed-phase high-performance liquid chromatography (RP-HPLC) in that it used high levels of acetonitrile (ACN) at low pH. The optimized FZCE buffer system consisted of 80 mM phosphate-glycine buffer, nominal pH 2.5, containing 60% ACN and a cellulose derivative to dynamically coat capillary walls. Resolution was similar to or higher than that previously achieved by FZCE buffers utilizing 8 M urea as a buffer additive. ACN concentrations of at least 50% were necessary to achieve acceptable separations; this ACN concentration is approximately that necessary to extract these storage proteins. ACN was equally effective as traditional ethanol solvents and 8 M urea for solubilizing maize and sorghum proteins. The ACN-based FZCE buffer system gave high repeatability (<0.3% relative standard deviation, measured over 15 consecutive injections) for migration time. Subclasses of maize and sorghum storage proteins were identified, and genotypes of each cereal were successfully differentiated using ACN-containing buffers. This FZCE method may be applicable for the analysis of other hydrophobic proteins without the use of urea. 相似文献
20.
Maize ( Zea mays L.) and sorghum ( Sorghum bicolor L.) Moench (local variety called Masakwat) plants were grown in a sterilized low-P soil in the greenhouse for 12 weeks. Each plant species was either mycorrhizal with vesicular-arbuscular mycorrhizal (VAM) fungi, non-mycorrhizal but minimally fertilized with soluble P, or non-mycorrhizal but highly fertilized with soluble P. Drought stress was imposed after 4 weeks at weekly intervals. Under unstressed conditions, leaf area, shoot dry weights, xylem pressure, and soil water potentials were similar for VAM and the two non-mycorrhizal P-fertilized treatments but each of the VAM-infected species had a greater total root length. Total P uptake was similar for the maize treatments but higher for VAM than non-mycorrhizal P-fertilized sorghum treatments. Under drought-stressed conditions, the growth parameters and soil water potential were similar for all maize treatments but they were reduced by mycorrhizal inoculation in sorghum. Greater water extraction occurred in drought-stressed mycorrhizal sorghum. In both plant species, total P uptake and P uptake per unit root length (including unstressed species) were significantly enhanced in non-mycorrhizal P-fertilized treatments compared with the mycorrhizal treatment. Except for the root dry weight of sorghum plants, there were no differences in the growth parameters and P uptake between minimally and highly P-fertilized non-mycorrhizal treatments for either maize or sorghum. The increased total root length in drought-stressed mycorrhizal sorghum plants and the similar infected root lengths in unstressed and drought-stressed sorghum plants may have caused high C partitioning to drought-stressed mycorrhizal roots and therefore caused the reduced growth parameters in mycorrhizal plants compared to the non-mycorrhizal P-fertilized counterparts. The results indicate that P fertilization in addition to mycorrhizal inoculation may improve the drought tolerance of maize and sorghum plants. 相似文献
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