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1.
Vitamin A deficiency in humans is a widespread health problem. Quality protein maize (QPM) is a popular food rich in lysine and tryptophan, but poor in provitamin A (proA). Here, we report the improvement of an elite QPM inbred, HKI1128Q for proA using marker‐assisted introgression of crtRB1‐favourable allele. HKI1128 was one of the parental lines of three popular hybrids in India and was converted to QPM in our earlier programme. Severe segregation distortion for crtRB1 was observed in BC1F1, BC2F1 and BC2F2. Background selection by 100 SSRs revealed mean recovery of 91.07% recurrent parent genome varying from 88.78% to 93.88%. Across years, introgressed progenies possessed higher mean β‐carotene (BC: 9.22 µg/g), β‐cryptoxanthin (BCX: 3.05 µg/g) and provitamin A (proA: 10.75 µg/g) compared to HKI1128Q (BC: 2.26 µg/g, BCX: 2.26 µg/g and proA: 3.38 µg/g). High concentration of essential amino acids, viz. lysine (mean: 0.303%) and tryptophan (0.080%) in endosperm, was also retained. Multi‐year evaluation showed that introgressed progenies possessed similar grain yield (1,759–1,879 kg/ha) with HKI1128Q (1,778 kg/ha). Introgressed progenies with higher lysine, tryptophan and proA hold immense potential as donors and parents in developing biofortified hybrids.  相似文献   

2.
Simple sequence repeat polymorphism in Quality Protein Maize (QPM) lines   总被引：2，自引：0，他引：2  
A set of 23 Quality Protein Maize (QPM) lines, including 13 lines developed in India and 10 lines at CIMMYT (International Maize and Wheat Improvement Center), Mexico, was analyzed using microsatellite or simple sequence repeat (SSR) markers. Polymorphic profiles for 36 SSR loci have aided in differentiating the QPM inbred lines. The study resulted in identification of SSR markers, such as bnlg439, phi037, bnlg125, dupssr34 andbnlg105, with high polymorphism information content in the selected QPM genotypes. Detection of 30 unique/rare SSR alleles could contribute to effective differentiation of 14 of the 23 QPM inbreds. An opaque2-specific microsatellite marker, phi057, also facilitated differentiation of opaque2-carrying QPM inbreds from the non-opaque genotypes. Analysis using SSR markers indicated high levels of heterozygosity in majority of the Indian QPM lines and in one CIMMYT QPM inbred, CML188. Cluster analysis using SSR data, followed by canonical discriminant analysis, clearly distinguished the Indian QPM inbreds from those developed at CIMMYT. The cluster patterns were largely in congruence with the available pedigree information of the QPM inbreds studied. The study demonstrates the effectiveness of SSR markers in QPM genotype discrimination and analysis of genetic relationships, and could potentially contribute towards effective utilization of the elite QPM germplasm in Indian maize breeding programmes. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

3.
Vivek Maize Hybrid 9‐ a popular single‐cross hybrid developed by crossing CM 212 and CM 145 was released for commercial cultivation in India. The parental lines, being deficient in lysine and tryptophan, were selected for introgression of opaque‐2 allele using CML 180 and CML 170 as donor lines through marker‐assisted backcross breeding. The opaque‐2 homozygous recessive genotypes with >90% recovery of the recurrent parent genome were selected in BC2F2, and the seeds with <25% opaqueness in BC2F3 were forwarded for seed multiplication. Vivek Quality Protein Maize (QPM) 9, the improved QPM hybrid, showed 41% increase in tryptophan and 30% increase in lysine over the original hybrid. The grain yield of the improved hybrid was on par with the original hybrid. The newly improved QPM maize hybrid released in 2008 will help in reducing the protein malnutrition because its biological value is superior over the normal maize hybrids. This short duration QPM maize hybrid has been adopted in several hill states of North Western and North Eastern Himalayan regions.  相似文献   

4.
Maize is the major staple food in southern Africa with human consumption averaging 91 kg capita?1 year?1, and normal maize is nutritionally deficient in two essential amino acids: tryptophan and lysine. Despite the development of quality protein maize (QPM) with high tryptophan and lysine, stunting and kwashiorkor remain high in sub-Saharan Africa due to lack of high yielding and adapted QPM varieties. This study aimed at evaluating a new generation of QPM varieties for yield and related agronomic traits. Before the QPM varieties were validated on-farm, they were simultaneously selected on-station under five different management conditions. In the 2014/2015 season, 10 elite QPM varieties were selected from on-station trials based on high grain yield and stability, and were compared with the best commercial check varieties on-farm. During the 2015/2016 season, some poorly performing QPM varieties were dropped while new ones were added, resulting in 12 elite QPM varieties being evaluated on-farm. Analysis of variance for the 2014/2015 season showed non-significant hybrid × management condition interaction. Mean grain yields across management conditions ranged from 1.5 to 4 t ha?1 and were higher under mild stress (2.3–5.5 t ha?1) compared to random stress conditions (1.1–2.9 t ha?1). Broad sense heritability estimates were low to moderate (11–69%), and thus could still permit effective selection of better genotypes. Yield advantage ranged from 12 to 25% across the 2 years, suggesting effective genetic gains in QPM breeding. QPM hybrids CZH132044Q, CZH142238Q and CZH142236Q were stable and high yielding. Promotion of such QPM hybrids may help reduce protein energy malnutrition.  相似文献   

5.
The number of drought and low-N tolerant hybrids with elevated levels of provitamin A (PVA) in sub-Saharan Africa could increase when PVA genes are optimized and validated for developed drought and low-N tolerant inbred lines. This study aimed to (a) determine the levels of drought and low-N tolerance, and PVA concentrations in early maturing PVA-quality protein maize (QPM) inbred lines, and (b) identify lines harbouring the crtRB1 and LcyE genes as sources of favourable alleles of PVA. Seventy early maturing PVA-QPM inbreds were evaluated under drought, low-N and optimal environments in Nigeria for two years. The inbreds were assayed for PVA levels and the presence of PVA genes using allele-specific PCR markers. Moderate range of PVA contents was observed for the inbreds. Nonetheless, TZEIORQ 55 combined high PVA concentration with drought and low-N tolerance. The crtRB1-3′TE primer and the KASP SNP (snpZM0015) consistently identified nine inbreds including TZEIORQ 55 harbouring the favourable alleles of the crtRB1 gene. These inbreds could serve as donor parents of the favourable crtRB1-3′TE allele for PVA breeding in maize.  相似文献   

6.
From mutant pools of two Taiwanese elite japonica cultivars, Tainung 67 and Taikeng 8, we identified 13 mutant lines possessing opaque endosperm with relatively low amylose contents (AC) ranging from 1.5% to 7.1%. Because of different AC, paste viscosities of these 13 mutant lines differed, as revealed by palatability and physicochemical properties. The mutated gene conferring opaque endosperm was isolated from the F2 population of one mutant line, WY1× indica cv. ‘Taichung Sen 17’, by positional cloning, revealing a G3018→A3018 substitution at exon 9 of Waxy leading to a non‐synonymous mutation from alanine to valine. Two additional alleles were identified from the other 12 mutant lines, for which single‐nucleotide substitutions G2708 → A2708 and G3029 → A3029 occurred in exons 8 and 9, leading to non‐synonymous mutations from arginine to histidine and glutamic acid to lysine, respectively. The three novel wx alleles had different effects on grain quality, specifically on eating and cooking quality, and could be applied in rice breeding programmes to develop new low AC varieties by marker‐assisted selection.  相似文献   

7.
Mungbean (V. radiata) is an important Asiatic legume supplying inexpensive protein to a vast majority of vegetarian masses. To increase markers repertoire in mungbean, a study was conducted to analyse 384 microsatellite markers derived from common bean, scarlet runner bean and adzuki bean for their transferability and polymorphism. The results showed that 87 (24.71%) primer pairs could amplify DNA loci of 20 mungbean genotypes including one accession of V. trilobata, while 52 showed reliable banding and polymorphism. These showed different degrees of variability at each locus producing 250 alleles with the number of alleles varying from 2 to 9. The major allele frequency varied from 0.17 to 0.95, while the polymorphic information content of SSRs ranged between 0.09 and 0.86 with an average of 0.60 ± 0.16. UPGMA revealed three major clusters accommodating ~95% of the accessions while one accession of V. trilobata (‘NSB‐007’) did not group with any other genotype describing the discriminating power of informative microsatellites. This study identified a set of useful microsatellite markers to accelerate the genetic studies and breeding programme of mungbean.  相似文献   

8.
Preharvest aflatoxin (AF) contamination by Aspergillus flavus Link:Fr is one of the main limitations for maize (Zea mays, L.) production in the southern USA, causing enormous economic losses and posing a risk to animal and human health. The objectives of this study were (1) to estimate aflatoxin accumulation and expression of associated traits in quality protein maize (QPM) inbreds and their testcrosses, (2) to compute their repeatabilities and correlations, and (3) to study the relationship between inbred lines and their testcrosses for aflatoxin accumulation. Forty-eight inbreds and their testcrosses plus checks were grown in one and three locations in south and central Texas, respectively. Aflatoxin concentration was evaluated in the plants following inoculation with A. flavus. Average aflatoxin concentration overall for inbreds was 286.3 ng g−1, and for testcrosses 596.5 ng g−1 at Corpus Christi, TX, 325.1 ng g−1 at Weslaco, TX, and 105.1 ng g−1 at College Station, TX. Flinty orange inbreds developed from CIMMYT Population 69 were the least susceptible to aflatoxin accumulation in both inbreds and testcrosses at all locations. Repeatability for aflatoxin was 0.67 in inbreds at Weslaco, TX and 0.54 in testcrosses across locations. Aflatoxin in testcrosses was positively correlated both phenotycally and genotypically with endosperm texture and kernel integrity, and negatively correlated with grain yield and silking date. Less aflatoxin accumulation was associated with flinty endosperm texture, better kernel integrity, and later maturities. Association between the expression of traits in inbreds and aflatoxin in testcrosses was relatively high for endosperm texture (R 2 = 0.62), silking date (R 2 = 0.44), kernel integrity (R 2 = 0.39), and aflatoxin (R 2 = 0.60 for log ng g−1). It seems plausible to select for associated traits having high heritabilities and strong correlation with aflatoxin, in addition to low aflatoxin accumulation in inbreds and hybrids to reduce the risk of aflatoxin contamination.  相似文献   

9.
L. R. Pinto    K. M. Oliveira    T. Marconi    A. A. F. Garcia    E. C. Ulian    A. P. de Souza   《Plant Breeding》2006,125(4):378-384
Microsatellites or simple sequence repeats (SSRs) are one of the most suitable markers for genome analysis as they have great potential to aid breeders to develop new improved sugarcane varieties. The development of SSR derived from expressed sequence tags (EST) opens new opportunities for genetic investigations at a functional level. In the present work, the polymorphism obtained with a subset of 51 EST–SSRs derived from sucest was compared with those generated by 50 genomic SSRs (gSSR) in terms of number of alleles, polymorphism information content, discrimination power and their ability to establish genetic relationships among 18 sugarcane clones including three Saccharum species (S. officinarum, S. barberi, S. sinense). The majority of EST–SSRs loci had four to six alleles in contrast to the seven to nine observed for the gSSRs loci. Approximately, 35% of the gSSRs had PIC values around 0.90 in contrast to 15% of the EST–SSRs. However, the mean discrimination power of the two types of SSR did not differ significantly as much as the average genetic similarity (GS) based on Dice coefficient. The correlation between GS of the two types of SSRs was high (r = 0.71/P = 0.99) and significant. Although differences were observed between dendrograms obtained with each SSR type, both were in good agreement with pedigree information. The S. officinarum clone IJ76‐314 was grouped apart from the other clones evaluated. The results here demonstrate that EST–SSRs can be successfully used for genetic relationship analysis, extending the knowledge of genetic diversity of sugarcane to a functional level.  相似文献   

10.
糯玉米opaque2基因近等基因系的创制   总被引：3，自引：0，他引：3  
opaque2基因能够提高糯玉米赖氨酸、色氨酸等必需氨基酸的含量。用2种优质蛋白玉米(QPM)CA339和鲁2548自交系作为opaque2基因供体,25个品质较好的糯玉米自交系作为受体,利用回交技术和SSR分子标记辅助选择育种,创制糯玉米opaque2近等基因系。分子标记结果表明,不同受体以及两种供体间都存在多态性。5套创制成功的opaque2近等基因系的赖氨酸含量比其轮回亲本分别提高了59.0%、52.7%、48.5%、46.3%和61.9%,分别由0.308%、0.313%、0.309%、0.341%、0.323%提高到0.489%、0.478%、0.458%、0.498%、0.522%。本研究表明,可以利用此方法通过向不同遗传背景的多种受体导入opaque2,选取赖氨酸含量提高较大、透明表型的近等基因系,提高糯玉米的营养价值和经济价值。  相似文献   

11.
Inheritance of zein components in maize has been studied by a highresolution system of acidic continuous polyacrylamide gel electrophoresis. This method revealed extraordinarily high polymorphism of zeins. Previously, three multigenic loci, Zep1, Zep2 and Zep3, encoding most zein polypeptides were identified. Four other loci control the synthesis of some minor components. Single F2 grains from 16 hybrid combinations involving 19 inbred lines were analysed. Correspondingly, 12 and 14 alleles of the Zep1 and the Zep2 loci were identified for 19 inbreds. Six alleles of the Zep3 locus were identified in five crosses. All 32 alleles of three multigenic loci were included in the catalogue of zein alleles. Genetic nomenclature for the alleles designation is proposed. Such nomenclature is in good agreement with ‘a standard for maize genetics nomenclature. The catalogue may serve for practical use and as basis for more detailed genetic studies of zeins. Practical application of the catalogue in maize breeding is discussed.  相似文献   

12.
Lagerstroemia (crape myrtle) are famous ornamental plants with large pyramidal racemes, long flower duration and diverse colours. Genetic maps provide an important genomic resource of basic and applied significance. A genetic linkage map was developed by genotyping 192 F1 progeny from a cross between L. caudata (female) and L. indica (‘Xiang Xue Yun’) (male) with a combination of amplification fragment length polymorphisms (AFLP) and simple sequence repeats (SSR) markers in a double pseudo‐testcross mapping strategy. A total of 330 polymorphic loci consisting of 284 AFLPs and 46 SSRs showing Mendelian segregation were generated from 383 AFLP primer combinations and 150 SSR primers. The data were analysed using JoinMap 4.0 (evaluation version) to construct the linkage map. The map consisted of 20 linkage groups of 173 loci (160 AFLPs and 13 SSRs) covering 1162.1 cM with a mean distance of 10.69 cM between adjacent markers. The 20 linkage groups contained 2–49 loci and ranged in length from 7.38 to 163.57 cM. This map will serve as a framework for mapping QTLs and provide reference information for future molecular breeding work.  相似文献   

13.
A collection of Portuguese maize accessions representing a valuable source of genes for introduction into modern cultivars is stored at the Portuguese Plant Germplasm Bank (Banco Português de Germoplasma Vegetal—BPGV). To assess genetic diversity among inbreds, microsatellite analysis was carried out for 54 inbred lines representing the diversity of Portuguese dent and flint maize germplasm. Fifty American and other European elite inbreds were also analysed for comparison. Fifteen microsatellite loci distributed throughout the maize genome were chosen based on their repeat unit and base composition. A total of 80 alleles were detected with an average allele number of 5.33 per locus. Polymorphism information content (PIC) values and observed genetic distances showed the existence of large variability among inbreds. Cluster analysis indicated that almost all of the inbreds could be distinguished from each other and Portuguese inbreds were present in all clusters formed. These associations were consistent with the known pedigree records of the inbreds, confirming a mixed origin of Portuguese materials. Comparative analysis of microsatellite diversity among groups was established according to important traits for both breeding and line identification. This revealed that, although most of the genetic diversity (>95%) was attributable to differences among inbreds of different groups, the existence of phenotypic differentiation in endosperm colour, kernel type and cob colour could be suggested for grouping. These findings support the joint use of molecular and morphological traits in management of the germplasm collection. In this study, SSR markers proved to be effective to characterise and identify maize inbred lines, and demonstrate associations among them. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

14.
Microsatellite or simple sequence repeat (SSR) markers are important tools for genetic analyses, especially those targeting diversity. The primary objective of this study was to develop robust oat‐based microsatellite markers from newly enriched genomic libraries to expand on a relatively small existing oat SSR toolbox. Microsatellite motifs characterized by (CA/GT), (AAT/TTA), (ATG/TAC) and (CATC/GTAG) repeats were targeted for enrichment. Preliminary screening showed that 90% of clones from the (CA/GT) and 79% of the clones from the (ATG/TAC) libraries contained repeats, while < 11% of the clones from (AAT/TTA) and (CATC/GTAG) libraries contained repeats. Subsequent sequencing of 1536 clones from the (CA/GT) and (ATG/TAC) libraries resulted in 539 and 578 SSRs for which primers were designed, respectively. A total of 246 SSRs were polymorphic across 11 oat lines. One hundred and twenty‐five of the markers produced highly reproducible assays that interrogated 369 alleles at 193 loci. Of these, 79 robust assays interrogated 146 codominant alleles. These markers will be useful for a wide range of genetic analyses in oat including assessment of diversity and marker‐assisted breeding.  相似文献   

15.
籽粒硬度是小麦加工品质的重要影响因素.籽粒硬度生化标记Friabilin蛋白主要由Puroindoline A（PinA）和Puroindoline B（PinB）构成,它们的编码基因puroindoline a（Pina）和puroindoline b（Pinb）紧密连锁,位于Ha（hardness）位点,是控制籽粒硬度的主效基因.根据小麦Pina、Pinb的保守序列,设计合成了2对特异性引物,对粘果山羊草Aegilops kotschyi（UUSS）3个材料的基因组DNA和胚乳RNA进行Pina、Pinb基因克隆、序列测定和表达分析,发现了3个新型Pina等位基因和4个新型Pinb等位基因.新型puroindoline等位基因全长447bp,编码148个氨基酸残基,具有麦类作物puroindoline基因特有的信号肽序列和色氨酸结构域.与Pina-D1a相比较,新型Pina等位基因核苷酸同源性分别为98.7%、98.4%、97.5%,氨基酸同源性分别为96.6%、95.9%、93.9%.等位基因Pina-allele-2包含一个位于色氨酸结构域内的突变位点（Lys70Arg）.新型Pinb等位基因与Pinb-D1a相比较,其核苷酸同源性分别为93.3%、94.6%、94.6%、94.4%,氨基酸同源性分别为90.5%、93.2%、93.2%、92.6%.等位基因Pinb-allele-1含有一个紧邻色氨酸结构域的突变位点（Val66Phe）.Southern blot分析结果表明,3个材料中Pina和Pinb基因都含有2个拷贝.RT-PCR和Western blot都证实了Pina、Pinb基因在籽粒胚乳中的表达.研究结果显示山羊草中包含着与小麦差异较大的籽粒硬度控制基因,为小麦分子育种提供了丰富的的遗传资源.  相似文献   

16.
The entire USDA‐ARS maintained collection of 650 accessions of proso millet (Panicum miliaceum L.) was evaluated for the presence of accessions with waxy (amylose‐free) endosperm starch. Six accessions, five of which derived from mainland China, were identified. Segregation ratios for waxy endosperm were evaluated in F2 and F3 populations derived from crosses between two waxy accessions, PI 436625 (Lung Shu 16) and PI 436626 (Lung Shu 18), and several wild‐type accessions. The waxy trait was found to be under the control of duplicate recessive alleles at two loci, herein designated wx‐1 and wx‐2. Wild‐type alleles at these loci were designated Wx‐1 and Wx‐2. Iodine‐binding revealed a mean grain‐starch amylose concentration of 3.5% in waxy lines and 25.3% in wild‐type proso. Expression of the granule‐bound starch synthase (waxy protein) in waxy lines was reduced to approximately one‐tenth that of wild‐type accessions. The waxy accessions identified now are available for the introgression of this trait into breeding lines adapted to the Great Plains of North America.  相似文献   

17.
Fusarium root rot is a common biotic restraint on pea yields, and genetic resistance is the most feasible method for improving pea production. This study was conducted to discover quantitative trait loci (QTL) controlling genetic partial resistance to Fusarium root rot caused by Fusarium solani (Mart.) Sacc. f.sp. pisi (F.R. Jones) W.C. Snyder & H.N. Hans (Fsp). A RIL population was screened in a Fusarium root rot field disease nursery for 3 years. Composite interval mapping was employed for QTL detection using the means of disease severity from three growing seasons. Five QTL were identified, including one QTL identified in all three years. The multiyear QTL Fsp‐Ps2.1 contributed to a significant portion of the phenotypic variance (22.1–72.2%), while a second QTL, Fsp‐Ps6.1, contributed 17.3% of the phenotypic variance. The other single growing season QTL are of additional interest as they colocate with previously reported pea–Fusarium root rot resistance QTL. QTL Fsp‐Ps2.1, Fsp‐Ps3.1, Fsp‐4.1 and Fsp‐Ps7.1 are flanked by codominant SSRs and may be useful in marker‐assisted breeding of pea for high levels of partial resistance to Fsp.  相似文献   

18.
X. C. Zhao  P. J. Sharp   《Plant Breeding》1998,117(5):488-490
Null alleles of the three loci coding for ‘waxy’ proteins in bread wheat have been identified. Plants carrying different null alleles were collected and segregation of the null alleles in both selfed and doubled haploid progeny of plants simultaneously heterozygous for the null alleles at each of the three loci were examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Mendelian segregation of these alleles in both types of progeny was shown, indicating that they can easily be utilized in breeding programmes. Iodine staining of the eight possible null phenotypes showed that only the triple null type had zero amylose in its endosperm starch.  相似文献   

19.
There is a need to develop the next generation of healthier crop products for an improved human and animal nutrition. Maize (Zea mays L.) cultivars with improved amino acid profiles are essential to diets focused on this crop. Breeders have added crop value with the development of quality protein maize (QPM). However, QPM cultivars have never been an option to farmer and ranchers in short-season environments. The objectives of this research were: (1) to adapt QPM genotypes to the northern U.S. through the North Dakota (ND) EarlyQPM Program, and (2) to develop new early generation SS and non-SS short-season QPM lines and populations for breeding purposes. Fifty-three inbred lines, including 47 QPM donor lines, five experimental North Dakota State University (NDSU) lines, and one ex-PVP line from industry, were selected to produce 94 early-QPM backcross populations. Considering earliness, protein content, and amino acid levels, 218 early generation lines were selected for producing testcrosses with industry testers. Experiments evaluating testcrosses were arranged in 10 × 10 and 12 × 12 partially balanced lattice designs across three ND locations in 2013 and 2014. A total of 48 lines were selected for further development, 17 representing the Stiff Stalk (SS) heterotic group and 31 representing the non-SS group. Selected lines showed, in hybrid combinations, not only above average grain yield, rate of dry down, and total protein content but also high levels of lysine, tryptophan, and methionine essential amino acids for feedstock nutrition. The results of this research show, for the first time, the successful adaptation of QPM genotypes to short-season environments. As a result, new ND EarlyQPM germplasms and lines have been developed for potential release.  相似文献   

20.
Summary Indica-type rice provides the staple food for two billion people in Third World countries. Several problems involved in the stable and sustained production of high quality food cannot be solved by traditional breeding. Methods have been established for gene transfer to Indica rice breeding lines to study possible contributions from genetic engineering. Experiments are in progress on the development of transgenic resistance towards Yellow Stem Borer, resistance towards Rice Tungro Virus, accumulation of provitamin A in the endosperm, increase of essential amino acids in the endosperm such as lysine, cysteine and methionine and resistance towards fungal pests such as Rice Blast and Sheath Blight. Transgenic clones from Indica rice breeding lines have been recovered from several of the approaches mentioned, some of which have been regenerated to plants.  相似文献   

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