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PubMedDate not supplied

Cryopreservation of Malus germplasm using a winter vegetative bud method: results from 1915 accessions.

Cryopreservation using a winter vegetative bud method is being applied to the Malus collection maintained in the field at the USDA-ARS Plant Genetic Resources Unit, Geneva, New York. Winter hardy materials are sent to the USDA-ARS National Center for Genetic Resources Preservation, Fort Collins, CO, for processing. To date 1915 accessions, representing 30 species and 16 interspecific hybrids, have been tested. The NCGRP minimum standard for cryopreservation is 40% viable buds, as determined by grafting. For M. x domestica 95% of the accessions tested have been cryopreserved. For species other than M. x domestica, 83% have met the criterion. Eight lines were collected, cryopreserved and recovered through grafting each year. Data from this set showed an affect of year and cultivar on success. There was no strong relationship between viability after cryopreservation and phylogeny. For North American species success after cryopreservation was related to geographical origin.

Acclimatization↗
PubMed2005

[Identification of drought tolerant germplasm and inheritance and QTL mapping of related root traits in soybean (Glycine max (L.) Merr.)].

Fifty nine accessions of soybean (Glycine max (L.) Merr.) selected from 301 ones in Huang-Huai-Hai and Middle-Lower Changjiang Valleys were tested in two years for their tolerance to drought by using the mean membership index value averaged over those of plant height,leave number,dry root weight and dry stem and leaf weight. Four most tolerant accessions (Rank 1) and two most sensitive ones (Rank 5) were identified. There existed very significant correlations between drought tolerance and relative values of dry root weight,total root length, and root volume (per plant dry weight basis), respectively,which could be used as root indicators of drought tolerance. The RIL population derived from Kefeng 1 x Nannong 1138-2 was used to analyze the inheritance of the three related root traits by using the segregation analysis of quantitative traits under the major gene plus polygene mixed inheritance model. The results showed that between the two parents (Rank 1 x Rank 4), the relative values of dry root weight,total root length and root volume were respectively controlled by two major genes (linked together for the latter two traits, recombination value being 4.30% and 1.93%, respectively) plus polygenes with their major gene heritability values of 62.26%-91.81% and polygene heritability values 2.99%-24.75%, indicating that the major genes,especially the one with larger effect,accounted for a major part of the genetic variation between the two parents. It was identified that five, three, and five QTLs located on N6-C2, N8-D1b + W, N11-E, and N18-K linkage groups for relative dry root weight, total root length and root volume, respectively. Each of the traits appeared to have one locus (Dw1, R/1, and Rv1) with relatively large effect in comparison with their other loci, and those major ones were located near the same site of the same linkage group N6-C2. The results of segregation analysis and QTL mapping appeared pretty consistent with each other, which could be used as a demonstration of each other.

Adaptation, Physiological↗
PubMed2006

[RAPD analysis on germplasm resources of different farm races of Morinda officinalis].

OBJECTIVE: To explore the genetic diversity of different farm races of Morinda officinalis on molecular level. METHODS: The molecular biological technique-random amplified polymorphic DNA (RAPD) were used. RESULTS: Of the 40-mer arbitary primers, 14 were found to amplify polymorphic products. 3-5 polymorphic bands were amplified by each polymorphic primer on the average. Using UPGMA method all the tested accesions can be clustered into two groups: 4 accessions of Daye were classified as one group, 1 accession of Xiaoye be another group. CONCLUSION: There actually existed much genetic diversity on molecular level among the different farm races of Morinda officinalis.

Cluster Analysis↗
PubMed2006

[Genetic diversity of gliadin in wild germplasm of Elymus nutans Griseb].

Acid polyacrylamide gel electrophoresis (A-PAGE) was used to detect the gliadin genetic polymorphism among thirty-three wild accessions of Elymus nutans Griseb collected from four provinces and regions in China (Xinjiang, Qinghai, Sichuan and Tibet). The follows results were obtained. (1) A total of 38 bands were detected in all accessions, 92.1% were polymorphic bands. The average number of Shannon index to four electrophoretic zones was 0.55. The Nei's genetic similarity coefficient of the tested accessions ranged from 0.36 to 0.94, and the average Nei's coefficient was 0.63. These results suggested that there was rich genetic polymorphism among the tested wild resources of Elymus nutans Griseb. (2) 33 wild accessions can be clustered into seven groups at GS = 0.67 level on dendrogram. The principal coordinates (PCA) reflected almost the same relationships among the studied materials as shown in cluster analysis. Moreover, the groups from the same origin frequently clustered into one group. The findings implied that a correlation among gliadin patterns, geographical and ecological environment. (3) Genetic differentiation between and within five eco-geographical groups of Elymus nutans was estimated by Shannon's diversity index, which shown that 42.94% genetic variance existed within group, and 50.76% genetic variance was among groups. This result might be correlative to mainly self-pollinated breeding system of E. nutans. (4) UPGMA cluster analysis based on Nei's unbiased measures of genetic identity was assayed for five geographical groups of Elymus nutans, indicating that there was a significantly positive correlation between genetic differentiation and geographical habits among the five groups.

China↗
PubMed2006

[Soybean allergens and hypoallergenic germplasm enhancement].

Food allergy is a public sanitary problem which has received attention worldwide. It is becoming an increasingly interesting problem to decrease the concentration of allergens for improvement of the food security. Soybean allergens in seeds are composing of storage proteins, structure proteins, and disease-related proteins. Among them, Gly m Bd 28K, Gly m Bd 30K and Gly m Bd 60K are the major allergens located in 7S conglycinin fragments. By recognizing allergens' physicochemical property, hypersensitivity and gene structure, certain progresses had been made to reduce the concentration of allergens in soybean through food processing, traditional breeding and genetic engineering. The paper reviewed the sorts and characters of soybean allergens, the physicochemical property of the three immunodominant allergens and their gene structures. Progress in developing hypoallergenic cultivars was also discussed.

Allergens↗
PubMedDate not supplied

Cryopreservation of plant germplasm using the encapsulation-dehydration technique: review and case study on sugarcane.

Encapsulation-dehydration is a cryopreservation technique based on the technology developed for producing synthetic seeds, i.e. the encapsulation of explants in calcium alginate beads. Encapsulated explants are then precultured in liquid medium with a high sucrose concentration and partially desiccated before freezing. Encapsulating the explants allows the subsequent application of very drastic treatments including preculture with high sucrose concentrations and desiccation to low moisture contents which would be highly damaging or lethal to non-encapsulated samples. An encapsulation-dehydration protocol comprises the following steps: pretreatment, encapsulation, preculture, desiccation, freezing and storage, thawing and regrowth. Encapsulation-dehydration has been applied to around 40 different plant species. The optimization of the successive steps of the encapsulation-dehydration protocol is illustrated for sugarcane apices.

Cryopreservation↗
PubMed2006

[RAPD analysis on the germplasm resources of Gastrodia elata in Guizhou].

Genetic polymorphisms of genomic DNA of 15 samples from wild and culturaled Gastrodia elata Blume in Guizhou were analyzed by RAPD method. 12 effective primers are screened from 40 primers amplified a total number of 93 loci, among which 66 are polymorphic and the percentage of polymorphic loci (PPB) is 70.97%. UPGMA dendrogram analyzed by NTSYSpc, ver. 2.2 shows that Gastrodia elata have apparent genetic variance. Geological distribution and growing environment were significant factors for the polymorphism.

China↗
PubMed1996

Detection of sugarcane bacilliform virus in sugarcane germplasm.

Sugarcane bacilliform virus (SCBV), a badnavirus was found in sugarcane genotypes of Saccharum officinarum L., S. barberi Jesw., S. sinense Roxb., S. robustum Brand and Jesw., and Saccharum hybrids. In most of the suspected genotypes the virus was found associated with clear foliar symptoms. However, certain symptom-free clones carried the virus too. The virus was detected by immuno-electron microscopy (IEM) and enzyme-linked immunosorbent assay (ELISA) in suspected clones. The virions measured about 108-118 x 20-21 nm in size. The virus was serologically closely related to another badnavirus, banana streak virus (BSV). Virus titer was low in most of the genotypes. However, a close correlation between symptoms expression and virus titer existed in some genotypes.

Animals↗
PubMed1992

The biochemical composition and nutritional potential of the tribal pulse, Mucuna monosperma DC. ex Wight.

Two germplasms of the tribal pulse, Mucuna monosperma Dc. ex Wight, viz., Thirunelly Reserve Forest, Wynaad District (Kerala) and Siruvani Reserve Forest, Coimbatore District (Tamilnadu), were analysed for proximate composition, total (true) seed proteins, seed protein fractionation, amino acid composition, fatty acids, minerals and anti-nutritional factors. Crude proteins, crude lipids, ash and nitrogen free extractives constituted 23.10%, 4.36%, 3.80%, 61.74%, respectively, in Tamilnadu germplasm; whereas, in Kerala germplasm they constituted 20.13%, 8.99%, 3.60% and 61.69%, respectively. The calorific values of 100 g dry matter of seed material are 408.19 KCal (Kerala) and 378.60 KCal (Tamilnadu) germplasms. Essential amino acids like methionine, cystine, threonine and valine were found to be limiting in the seed proteins of both the germplasms. The fatty acids like lauric acid and palmitic acid are found to be common in both the germplasm seed samples, while linoleic and oleic acids in Kerala germplasm and stearic acid in Tamilnadu germplasm are present. The Tamilnadu germplasm seems to be a rich source of sodium, magnesium, zinc, manganese, copper and iron; whereas the Kerala germplasm seems to be a rich source of phosphorus. Antinutritional substances like total free phenols, tannins, L-DOPA, trypsin inhibitor activity and phytohaemagglutinating activity also were investigated.

Amino Acids↗
PubMed2004

Recovery of exotic alleles in semiexotic maize inbreds derived from crosses between Latin American accessions and a temperate line.

Genetic diversity of elite maize germplasm in the United States is narrow relative to the species worldwide. Tropical maize represents the most diverse source of germplasm. To incorporate germplasm from tropical maize landraces into the temperate gene pool, 23 Latin American maize accessions were crossed to temperate inbred line Mo44. During inbred line development, selection was practiced in temperate environments, potentially resulting in the loss of substantial proportions of tropical alleles. Genotyping 161 semiexotic inbreds at 51 simple sequence repeat (SSR) loci permitted the classification of their alleles as either Mo44 or tropical and allowed estimation of the proportion of detectable tropical alleles retained in these lines. On average, the percentage of detectable tropical alleles ranged among lines from 15% to 56%, with a mean of 31%. These are conservative, lower-bound estimates of the proportion of tropical germplasm within lines, because it is not known how frequently Mo44 and the tropical maize accession parental populations shared SSR alleles. These results suggest that substantial proportions of exotic germplasm were recovered in the semiexotic lines, despite their selection in temperate environments. The percent of tropical germplasm in semiexotic lines was not correlated to grain yield or moisture of lines testcrossed to a Corn Belt Dent tester, indicating that the incorporation of a substantial percentage of tropical germplasm in an inbred line does not necessarily negatively impact its combining ability. Thus, tropical maize accessions represent a good source of exotic germplasm to broaden the genetic base of temperate maize without hindering agronomic performance.

Agriculture↗
PubMed2005

Non-transmission of bacterial and viral microbes to embryos and semen stored in the vapour phase of liquid nitrogen in dry shippers.

Cryopreservation and storage of germplasm is an important factor in the prevention of disease transmission by embryo transfer and artificial insemination. Here we report the results of an investigation on transmission of selected bacterial and viral pathogens by the vapour phase of liquid nitrogen (VPLN) to embryos and semen in dewars designed for short-term storage and transportation of biological specimens. In this study transmission of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, BVDV, and BHV-1 was examined from: (1) contaminated dry shippers to germplasm; (2) between contaminated and non-contaminated cryopreserved germplasm; and (3) between stock culture of pathogenic agents and germplasm. Contaminated and non-contaminated samples of embryos and semen were stored in proximity in the vapour phase LN in open containers for 7 days prior to testing for the presence of microbes. The results showed that there was no cross-contamination from either the contaminated dewars to germplasm or between contaminated and non-contaminated samples of embryos and semen during 7 days storage under LN vapours. The outcome of our investigation indicates that VPLN is a safe means for short-term storage of embryos and semen in dry shipper dewars commonly used for transportation of bovine germplasm.

Animals↗
PubMed1997

Conservation of rice genetic resources: the role of the International Rice Genebank at IRRI.

Rice genetic resources, comprising landrace varieties, modern and obsolete varieties, genetic stocks, breeding lines, and the wild rices, are the basis of world food security. The International Rice Genebank at the International Rice Research Institute in the Philippines conserves the largest and most diverse collection of rice germplasm. The facilities of the genebank ensure the long-term preservation of this important diversity. In field research, factors that affect long-term viability of rice seeds have been identified, leading to the introduction of modified practices for germplasm multiplication and regeneration. The value of conserved germplasm can be assessed in terms of useful traits for rice breeding and the economic impact that germplasm utilization has on rice production and productivity. The application of molecular markers is changing perspectives on germplasm management. International policies affecting access to and use of rice germplasm are discussed.

Conservation of Natural Resources↗
PubMed2003

Use of SSRs for establishing heterotic groups in subtropical maize.

Heterotic groups and patterns are of fundamental importance in hybrid breeding. The objectives of our research were to: (1) investigate the relationship of simple sequence repeats (SSR) based genetic distances between populations and panmictic midparent heterosis (PMPH) in a broad range of CIMMYT maize germplasm, (2) evaluate the usefulness of SSR markers for defining heterotic groups and patterns in subtropical germplasm, and (3) examine applications of SSR markers for broadening heterotic groups by systematic introgression of other germplasm. Published data of two diallels and one factorial evaluated for grain yield were re-analyzed to calculate the PMPH in population hybrids. Additionally, 20 pools and populations widely used in CIMMYT's breeding program were assayed with 83 SSR markers covering the entire maize genome. Correlations of squared modified Roger's distance (MRD(2)) and PMPH were mostly positive and significant, but adaption problems caused deviations in some cases. For intermediate- and early-maturity subtropical germplasm, two heterotic groups could be suggested consisting of a flint and dent composite. We concluded that the relationships between the populations obtained by SSR analyses are in excellent agreement with pedigree information. SSR markers are a valuable complementation to field trials for identifying heterotic groups and can be used to introgress exotic germplasm systematically.

Alleles↗
PubMed2002

Allozyme polymorphisms of maize populations from southwestern China.

Maize ( Zea mays L.) is one of the most-important food crops in southwestern China. The diversity of maize populations from southwestern China has been evaluated on the basis of agronomic and morphological data, but not on marker data. Our objectives were to evaluate the allozyme polymorphism of these populations, and group the populations on the basis of allozyme data. We analyzed 27 maize populations from southwestern China and two populations [BS13(S)C2 and Lancaster] from the USA for genetic variation at 18 allozyme loci. We found a total of 69 alleles at 18 allozyme loci with an average of 3.8 alleles per locus. Compared with inbreds, hybrids, and populations from the U.S. Corn Belt, the 27 Chinese populations had a significantly higher ( p<0.01) number of allozyme alleles per locus. Maize populations from southwestern China have accumulated abundant genetic diversity, and might be valuable germplasm for broadening the genetic base of U.S. Corn Belt breeding germplasm. The analyses of allele-frequency distributions and the expected heterozygosity also reflected the differences between the Chinese and the U.S. germplasm. The Chinese populations might be valuable germplasm for complementing U.S. Corn Belt breeding germplasm. The analysis of gene diversity showed that 77% of the allozyme variation resided within populations and 23% between populations. This result suggested that breeders should identify one or a few Chinese populations with the best agronomic performance, and exploit the genetic variation within these selected populations. Cluster analysis classified the 29 populations into four main groups. Groupings based on allozyme data could be useful for classifying the populations into different heterotic groups and, consequently, exploiting them in hybrid breeding.

Journal Article↗
PubMed2026

A robust biotechnology induces artificial genomic duplication via transient RNAi-mediated suppression of OSD1 in rice.

Ploidy manipulation is a crucial strategy for generating germplasm in crop breeding. However, artificial genomic duplication, often induced by colchicine treatment, is associated with toxicity and unpredictability. Although mutations in OSD1 have shown promise for inducing genomic duplication, the instability of ploidy across generations limits their practical application. In this study, we developed a Plant Polyploidization via Gene Interference (PPGI) system that utilizes transient RNAi-mediated suppression of OSD1 to efficiently induce artificial genomic duplication, demonstrating obvious potential for producing autotetraploids. We first validated this system by successfully generating PPGI-induced autotetraploid plants from the Taichung65 cultivar. These PPGI-induced plants exhibited notable differences from Taichung65 but resembled the existing Taichung65-4x line obtained through colchicine treatment. Haplotype analysis indicated that the OSD1 RNAi fragment is conserved across 2,908 rice cultivars. Consequently, we employed the same PPGI vector to develop autotetraploid lines from various germplasms, including another japonica cultivar, seven indica cultivars, and one Oryza rufipogon line. The probability of genomic duplication achieved by our PPGI method was higher than that obtained by colchicine treatment. Typically, autotetraploid lines exhibit severe sterility in the first generation following polyploidization. Leveraging fertile neo-tetraploid rice and the PPGI system, we designed and verified two strategies to directly induce fertile autotetraploid germplasms in the first generation, thereby substantially shortening the breeding cycle. Our method provides a universal, efficient, and non-toxic approach for inducing autotetraploid rice germplasms and contributes to enriching fertile autotetraploid rice germplasm resources.

OSD1↗