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1.
White-grained wheat cultivars have long been recognized to be less resistant to preharvest sprouting (PHS) than the red-grained ones. Previously two QTLs for grain dormancy, QPhs.ocs-3A.1 (QPhs-3AS) and QPhs.ocs-4A.1 (QPhs-4AL) were identified in a highly dormant Japanese red wheat, Zenkoujikomugi (Zen). Aiming at improvement of PHS tolerance in white-grained wheat, the introgression effect of these two QTLs in a white-grained population consisting of 40 recombinant inbred lines (RILs) developed from a cross between Zen and white-grained Spica was examined here. Random 20 RILs with red grains were also developed from the same cross and used as a control population. The RILs were grown in the field and in the glasshouse to evaluate the grain dormancy by germination test. Several SSR markers closely linked to the QPhs-3AS and QPhs-4AL were used to estimate the alleles at the QTLs. Dormancy variation in the RILs was significantly associated with the differences for grain color and the alleles at QPhs-3AS over several years. Although allelic variation was detected in a SSR marker closely linked to QPhs-4AL there was no difference in germination data between the Zen-allele and the Spica-allele groups. As expected, the red-grained RILs with the Zen allele at QPhs-3AS were the most dormant. Some white-grained RILs with the Zen allele at QPhs-3AS showed higher dormancy compared to the red-grained RILs with the alternative allele. These results demonstrated that introgression of the QPhs-3AS gene could contribute to the increased grain dormancy in white-grained wheat. 相似文献
2.
Pre-harvest sprouting (PHS) of wheat greatly reduces the quality and economic value of grain, and PHS resistance is one of the most important traits in wheat breeding. Red-grained wheat varieties are generally more resistant to PHS than white-grained ones; however, some are still susceptible. The red pigment of red-grained wheat is synthesized through the flavonoid biosynthetic pathway, in which the dihydroflavonol-4-reductase gene (DFR) is one of the genes involved in anthocyanin synthesis. In this study, a set of 120 red-grained Chinese wheat cultivars and lines with distinct PHS resistance were used to characterize TaDFR genotype variations and their association with PHS resistance. Whereas no variation or functional variation of TaDFR genes was detected on chromosomes 3A and 3D, a novel TaDFR allele, designated TaDFR-Bb, was explored on chromosome 3B. Compared with TaDFR-Ba, an 8 bp insertion (CTCTAGGA) was identified in the promoter region of TaDFR-B in most of the PHS resistant red-grained wheat varieties and advanced lines. Based on this, a CAPS marker was designed and validated with a set of Chinese red-grained wheat cultivars and lines with distinct PHS resistance. In most cases, TaDFR-Bb was associated with higher PHS resistance. An association study indicated that wheat varieties with the 8 bp insertion (average seed germination index 23.6 %) were significantly more resistant (P < 0.01) to PHS than those without the insertion (average seed germination index 69.5 %). Further study on gene expression demonstrated that the insertion led to increased TaDFR-B expression in cultivars with PHS resistance. Transient expression of TaDFR-B in coleoptiles of wheat cv. Chinese Spring revealed that increasing TaDFR gene expression did not induce the synthesis of anthocyanins. 相似文献
3.
Summary Distribution of two complementary genes Hwc-1 and Hwc-2 causing F1 weakness was examined using 159 native rice cultivars and 30 strains of wild relatives collected from various sites of tropical Asia including the Himalayan foothills. Hwc-1 is carried by a Peruvian cultivar, Jamaica, a tester cultivar of this experiment. It was not found in the tested cultivars and strains. Hwc-2 was widely distributed in the Japonica types tested. No wild strains had either Hwc-1 or Hwc-2. Hwc-2 was infrequent in the Japonica types collected from Southern Asian countries. Hwc-2 was estimated to be indigenous to the Japonica types, may be linked with certain gene(s) related to adaptation. 相似文献
4.
Development and application of allele-specific PCR assays for imazethapyr resistance in rice (Oryza sativa) 总被引：1，自引：0，他引：1
Outcrossing or cross hybridization is a potential concern in herbicide-resistant crop management strategies such as in the
Clearfield™ rice system. Recent studies have shown that the mutated acetolactate synthase (ALS) gene that confers resistance to imazethapyr (Newpath) herbicide can be transferred from Clearfield rice cultivars via cross
pollination under field conditions to weedy red rice. Resistance of commercial Clearfield rice cultivars to imazethapyr is
due to the presence of two point mutations in the ALS gene that result in amino acid substitutions from serine to asparagine (S to D) and glycine to glutamic acid (G to E). We
report here development of a DNA-based method that involves application of allele-specific PCR assays to distinguish herbicide-susceptible
and resistant ALS alleles in either homozygous or heterozygous genotypes produced from natural outcrosses between Clearfield varieties CL121,
CL141, CL161 and weedy red rice. PCR assays that can distinguish between the homozygous and heterozygous imazethapyr-resistant
S653D and G654E SNP alleles of the rice ALS gene were developed and evaluated. A total of 483 individual red rice plants were successfully screened for the presence
of S653D SNP and another 145 F2 individuals from natural red rice × CL121 hybridizations were screened for the presence of the G654E SNP. The PCR-based assays produced during this study are simple, rapid, inexpensive, reproducible and require only standard
PCR and electrophoretic instruments that can be applied toward outcrossing evaluation and effective weed management strategies
for the Clearfield crop system. 相似文献
5.
A hybrid weakness phenomenon is controlled by a set of complementary genes, Hwc1 (hybrid weakness c) and Hwc2, in rice. The Hwc2 gene is prevalent among temperate Japonica but not among tropical Japonica or Indica. In this study, the chromosomal location of the Hwc2 locus was determined from the segregation in the F1 hybrids made between 127 recombinant inbred lines and the cultivar ‘Jamaica’. Hwc2 was located between the two restriction fragment length polymorphism loci, XNpb264 and XNpb197 on chromosome 4. Further analysis indicated that Hwc2 was closely linked to Ph (phenol staining). The genetic and phylogenetic significance of the Hwc2 locus and the surrounding chromosomal region is discussed. 相似文献
6.
Elevated ultraviolet‐B (UV‐B; between 290 and 320 nm) radiation, because of depletion of the stratospheric ozone layer, is one of the major environmental factors influencing plant metabolic processes and yield. The southern US rice cultivars contribute greatly towards US rice production, but the effects of elevated UV‐B radiation on these cultivars are not well known. The objective of this study was to determine the effects of elevated UV‐B radiation on leaf photosynthetic rate (Pn), membrane stability, pollen viability, phenolic concentration and yield of eight commercially popular southern US rice cultivars (five inbred cultivars and three hybrids). Plants were grown in a temperature‐controlled greenhouse in Beaumont, TX, USA, and were exposed to UV‐B radiation of 0, 8 or 16 kJ m?2 day?1 for 90 days. For most of the cultivars, plants grown under 8 or 16 kJ UV‐B radiation showed significant decreases in Pn, membrane stability, pollen viability, and yield compared with the plants grown under an UV‐B‐free environment, whereas there was a significant increase in leaf phenolic concentration under 16 kJ UV‐B radiation. The hybrid ‘Clearfield XL729’ performed best among the selected southern US rice cultivars under 16 kJ UV‐B radiation. 相似文献
7.
8.
Ives Clayton Gomes dos Reis Goulart Marcelo Teixeira Pacheco Anderson Luis Nunes Aldo MerottoJr 《Euphytica》2012,187(3):437-447
Several red rice biotypes have evolved resistance to imidazolinone herbicides. The origin of resistance has been attributed to gene flow from the herbicide-resistant rice cultivars, but independent evolution of spontaneous mutation can also contribute to the herbicide resistance. The objective of this study was to quantify the occurrence of gene flow and independent selection as the mechanisms of origin of imidazolinone-resistance in red rice to correctly define the management practices for red rice control. Three single nucleotide polymorphism markers were used to identify acetolactate synthase (ALS) gene mutations, and four simple sequence repeat markers were used to identify hybrids of imidazolinone-resistant rice cultivars and red rice. In addition, genetic diversity and population structure analyses were performed. Artificial hybrids were used as controls. Gene flow was the main origin of imidazolinone herbicide resistance, but independent selection occurred in 1.1 % of the evaluated red rice plants. Two red rice plants that independently evolved herbicide resistance had the ALS gene mutation, Gly654Glu. Population structure analysis also indicated intense gene flow from rice cultivars to red rice, but some populations maintained a high genetic identity based on a small amount of gene introgression from the rice cultivars. These results indicate the importance of adopting controls of red rice escapees to avoid gene flow from the imidazolinone-resistant rice, and the necessity of biotechnological approaches to mitigating gene flow in the development of new herbicide-resistant rice cultivars. 相似文献
9.
The genetic relationship among three cytoplasmic male sterility (CMS) systems, consisting of WA, Dissi, and Gambiaca, was
studied. The results showed that the maintainers of one CMS system can also maintain sterility in other cytoplasmic backgrounds.
The F1 plants derived from crosses involving A and R lines of the respective cytoplasm and their cross-combination with other CMS
systems showed similar pollen and spikelet fertility values, indicating that similar biological processes govern fertility
restoration in these three CMS systems. The results from an inheritance study showed that the pollen fertility restoration
in all three CMS systems was governed by two independent and dominant genes with classical duplicate gene action. Three F2 populations, generated from the crosses between the parents of good-performing rice hybrids, that possess WA, Dissi, and
Gambiaca CMS cytoplasm, were used to map the Rf genes. For the WA-CMS system, Rf3 was located at a distance of 2.8 cM from RM490 on chromosome 1 and Rf4 was located at 1.6 cM from RM1108 on chromosome 10. For the Dissi-CMS system, Rf3 was located on chromosome 1 at 1.9 cM from RM7466 and Rf4 on chromosome 10 was located at 2.3 cM from RM6100. The effect of Rf3 on pollen fertility appeared to be stronger than the effect of Rf4. In the Gambiaca-CMS system, only one major locus was mapped on chromosome 1 at 2.1 cM from RM576. These studies have led
to the development of marker-assisted selection (MAS) for selecting putative restorer lines, new approaches to alloplasmic
line breeding, and the transfer of Rf genes into adapted cultivars through a backcrossing program in an active hybrid rice breeding program. 相似文献
10.
Seventeen rice cultivate resistant to brown planthoppers were genetically analyzed using the Bangladesh insect population. Seven cultivars were found to have a single dominant gene for resistance. These genes segregated independently of the recessive resistance gene bph-5. Tae dominant resistance gene of ‘Swarnalata’ was designated Bph-6. In ten cultivars, resistance is conferred by single recessive genes. In eight cultivars, the resistance genes are allelic to bph-5. However, the recessive genes o: two cultivars are non-allelic to bph-5. The recessive gene of T12 is designated bph-7. 相似文献
11.
12.
Summary Four indica cultivars viz. Kalinga-I, Ptb. 10, IR 27280-13-3-3-3 and Co. 41 were found to possess male sterile cytoplasm with fertility restoring genes while the cultivar Krishna was found to maintain the male sterility in all the cases. All the plants in the F1 of Kalinga-I × Krishna were observed to be completely male sterile and continued to show complete pollen sterility in subsequent backcross generations when backcrossed with recurring pollen parent, Krishna. Thus, it was posible to develop a new cytoplasmic-genetic male sterile line in indica rice (Krishna A) with Kalinga-I male sterile cytoplasm and this male sterile cytoplasm was found to be genetically different from others. Further, the newly developed male sterile line (Krishna A) was observed to be tolerant for low temperature at seedling stage. 相似文献
13.
Summary Rice cultivars (Oryza sativa L.) belonging to five ecotypes (aus, aman, boro, bulu and tjereh) and to two groups of Japanese rice (lowland and upland) are examined with respect to KClO3 resistance, phenol reaction and apiculus hair length. These characters have been used as available criteria to classify rice into two types indica and japonica, for the last thirty years.The findings of this study are that the aman, boro and tjereh ecotypes should be classified as typical indica; and that the Japanese lowland rice cultivars are mainly typical japonica. Some of the aus, bulu and Japanese upland rice cultivars differ from typical indica and typical japonica, so the respective terms aus type, bulu type and J.u.r. type, are proposed.
Aman, boro tjereh and Japanese lowland rice are cultivated in lowland. Some of the aus, bulu and Japanese upland rice cultivars have the characteristics of upland rice. In general, lowland rice cultivars can be clearly classified into indica or japonica, while upland cultivars cannot.Abbreviations
Aph
dominant gene for apiculus hair length > 0.7 mm
-
aph
recessive gene for apiculus hair length < 0.7 mm
-
J.u.r. type
Japanese upland rice type 相似文献
14.
The inheritance of resistance to rice gall midge (Ranchi biotype) was studied in 12 resistant cultivars by crossing with susceptible cultivars. By the study of F1, F2, F3, B1 and B2 generations, it was found that resistance was governed by a single dominant gene in ‘Surekha’, ‘Phalguna’, ‘Rajendra Dhan 202’, ‘IET 7918’‘IET 6187’, ‘BG 404-1’; by duplicate dominant genes in ‘W 1263’, ‘RPW 6-17’ and ‘WGL 48684’ and a monogenic recessive gene in ‘OB 677’ and ‘BKNBR 1008-21’. The allelism test of the resistant genes in the test cultivars with already known genes Gm1 and Gm2 was carried out. A single dominant gene that conveyed the resistance in ‘RPW 6–17’, ‘IET 7918’ and ‘IET 6187’ was allelic to Gm1 and segregated independently of Gm2. The resistance in ‘Phalguna’, ‘Rajendra Dhan 202’, ‘W 1263’ and ‘RPW 6–17’, ‘IR 36’ and ‘WGL 48684’ was governed by Gm2 gene which was independent of Gm1. Two additional genes were identified and designated as Gm3 and gm4. Three test cultivars ‘BG 404-1’, ‘W 1263’ and ‘WGL 48684’ were found to have Gm3 gene for resistance which was non-allelic and segregated independently of Gm1 and Gm2. Thus the cultivars ‘W 1263’ and ‘WGL 48684’ had two resistance genes Gw2 and Gm3 together. The cultivar ‘RPW 6–17’ also had two resistance genes Gm1 and Gm2 together. The recessive gene gm4 which conditioned the resistance in ‘OB 677’ and ‘BKNBR 1008-21’ was nonallelic to and segregated independently of Gm1, Gm2 and Gm3 genes. Linkage studies of the resistance gene with pigment characters were carried out in ‘Purple gora/IR 36’ cross. The resistance gene Gm2 was found to be linked with the genes governing the pigmentation in node, apiculus and stigma with crossover values of 15.78, 31.57 and 35.78 % respectively. By the trisomic analysis, it was found that the Gm2 gene was located on chromosome 3. 相似文献
15.
T.M. Linscott N.A. Bosque-Pérez D.J. Schotzko K.K. Kidwell R.S. Zemetra 《Euphytica》2001,121(1):31-35
The Russian wheat aphid, Diuraphis noxia (Mordvilko), is a major pest of cereal crops in many areas of the world, causing serious reduction in grain yield in wheat
(Triticum aestivum L.) and barley (Hordeum vulgare L.). Incorporating genetic resistance to D. noxia into wheat cultivars is paramount to effectively reduce damage inflicted by this pest. Genetic resistance to D. noxia has been identified in wheat, barley and rye germplasm, and several resistance genes are available for use for cultivar improvement.
In the United States of America, only a few Russian wheat aphid (RWA) resistant winter wheat cultivars are currently available,
and these cultivars contain only one of the six known RWA resistance genes. The objective of this study was to determine the
inheritance of RWA resistance in wheat accession PI 47545, using a screening method based on differences in the leaf morphology
of resistant and susceptible types following insect challenge. PI 47545 was selected for study, since it displayed high levels
of resistance in a white-grained wheat background, the predominant wheat class produced in the Pacific Northwest of the USA.
Segregation analysis was conducted on an F2 population developed by cross-hybridizing the susceptible soft white winter wheat cultivar ‘Daws’ to the resistant accession
PI 47545. Russian wheat aphid screening data from this population indicated that the resistance in PI 47545 is controlled
by a single, dominant gene (χ2 = 1.72; p ≤ 0.189).
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
16.
Passoupathy Rajendrakumar Akshaya Kumar Biswal Kannabiran Sakthivel Maganti Sheshu Madhav Chirravuri Neeraja Sena M. Balachandran Kommoju Srinivasarao Podishetty Natarajkumar Yadla Hari Kalidindi Sujatha Raman M. Sundaram 《Euphytica》2009,169(2):263-271
SSR markers targeting (GATA)
n
motifs are known to be highly polymorphic and useful in many organisms. (GATA)
n
motif specific SSR markers covering the whole rice genome are not available. The present study was carried out with an objective
to identify class I rice microsatellites in the rice genome with (GATA)n motifs, in-silico, and validate their potential as molecular markers. A total of 243 such motifs were identified; 65 of these
were present in the genic region, 59 were in the upstream region and the remaining motifs were found in the intergenic regions.
Many of the (GATA)
n
motifs were found within and/or upstream of genes associated with biotic or abiotic stress tolerance. A total of 230 PCR-based
markers targeting all the class I (GATA)
n
microsatellites were developed and 35 of these markers spread across the rice genome were validated in a set of 24 representative
rice varieties belonging to five distinct cultivar groups. All the markers were polymorphic, with average polymorphism information
content (PIC) value of 0.61, and the rice cultivars could be uniquely distinguished into different cultivar groups based on
marker analysis. These informative markers targeting (GATA)
n
motifs representing a new set of markers in rice will be highly useful for genetic studies and marker-assisted selection.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Passoupathy Rajendrakumar, Akshaya Kumar Biswal and Kannabiran Sakthivel contributed equally. 相似文献
17.
Exploring genetic diversity of rice cultivars for the presence of brown planthopper (BPH) resistance genes and development of SNP marker for Bph18 
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下载免费PDF全文 Gandhimani Ramkumar G. D. Prahalada Sherry Lou Hechanova Sung‐Ryul Kim Kshirod K. Jena 《Plant Breeding》2016,135(3):301-308
Brown planthopper (BPH) is the most devastating insect pest in rice‐growing areas. Information on availability of BPH resistance alleles and their sources enhances BPH‐resistant breeding programmes. In this study, 260 highly diversified rice cultivars or breeding lines were screened for the presence of five major BPH resistance genes (Bph10, Bph13, Bph18, Bph20 and Bph21) using gene‐specific markers. The analysis revealed that 137 of the 260 cultivars possess at least one BPH resistance gene. Bph10 was predominant while Bph20 was the least distributed. Moreover, two and three different resistance gene combinations were found in the cultivars. Molecular markers play an important role in molecular breeding programmes. A tightly linked PCR‐based co‐dominant Bph18 marker was developed, which is cost effective and time effective and simpler than available Bph18 CAPS marker (7312.T4A). We strongly believe that the identified BPH‐resistant cultivars can be used as alternative resistance gene sources and also as resource for novel BPH resistance genes. The developed Bph18 marker will be highly useful in molecular breeding applications of BPH‐resistant breeding programmes. 相似文献
18.
Bulb color in onions (Allium cepa) is an important trait, and homogenous red coloration is desirable in red onion cultivars. The gene encoding anthocyanin synthase (ANS) is required for anthocyanin biosynthesis in onions. We have previously described three different alleles of the ANS gene. Here we report identification of the fourth allele of ANS, ANS-h1, found in a dark red doubled haploid line. ANS-h1 is similar to a non-functional allele found in Brazilian yellow cultivars except that it has several point mutations and indels throughout the promoter and coding regions, none of which are predicted to inactivate enzymatic activity. F2 and backcross populations originating from the crosses between wild-type (ANS-L) allele-containing red and pink (ANS-p) allele-containing white or yellow parents show a discrete segregation ratio of 3 red to 1 light pink, indicating that the wild-type allele is completely dominant over the pink allele. In contrast, segregating populations derived from the crosses between ANS-h1 allele-containing red and the same white or yellow parents show a gradient of red intensity from light pink to dark red, suggesting that other genetic factors may affect expression of ANS-h1. A newly developed PCR-based marker and two previously developed markers for allelic selection of the ANS gene were used to examine allele composition in fifty-six breeding lines and commercial cultivars. Most lines are heterogeneous for the ANS gene with two or three alleles detected. The frequency of the pink allele is low in red breeding lines, but it is predominant in white and yellow lines. 相似文献
19.
The possibility of breeding white-grained wheats tolerant to pre-harvest sprouting under Japanese humid weather conditions
is discussed. New genetic dormancy sources, such as, AUS1408, 8019R1 and RyuuMai7, were evaluated for seed dormancy in different
weather conditions. Some white-grained dormant wheats showed a strong dormancy similar to that of red-grained dormant wheats
in a greenhouse trial, in the field their dormancy expression was much less than the red wheats. Three populations involving
crosses with these new sources for winter wheat breeding were examined under repeated selection for seed dormancy. Some dormant
white-grained lines, as judged under glasshouse conditions, were developed. Again the level of dormancy in these lines was
not sufficient compared to red dormant varieties in field trial. In order to develop truly superior dormant white-grained
materials, one population involving crosses with two dormant varieties, AUS1408 and 8019R1, was examined under repeated selection.
From these materials we succeeded in breeding lines that had not only a good dormancy but also showed adaptation to Japanese
weather conditions, including earliness, scab resistance and good seed appearance. However again the dormancy of these lines
in field trial was not sufficient compared to that of red wheats and there was not a clear difference for seed dormancy between
breeding lines and their parents. We conclude therefore that more work involving the use of new genetic sources or new breeding
techniques, will be necessary for breeding advanced lines that maintain a sufficient tolerance to PHS in humid Japanese weather
condition.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
Tomosaburo Yabuno 《Euphytica》1987,36(2):529-534
Summary It is shown that the restorer gene Rf
j
extracted from the Japanese rice variety Akebono is effective on pollen restoration in the cytoplasm substitution line having the nucleus of Oryza glaberrima and japonica or indica cytoplasm of O. sativa, and is of the sporophytic type.The Asian perennial type of the wild rice species O. rufipogon is considered to be the progenitor of O. sativa. Two substitution lines having the cytoplasm of a perennial strain of O. rufipogon from Sri Lanka and the nucleus of O. glaberrima with or without the gene Rf
j
in homozygous condition have been bred by means of successive backcrosses. These lines have now reached the BC5 generation. Plants of the lines resemble morphologically the recurrent parent, but do not show pollen restoration, indicating that the cytoplasm of the rufipogon strain induced male sterility and that the gene Rf
j
does not act as the restorer. 相似文献