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1.
Genetic effects determining rice grain weight and grain density   总被引：1，自引：0，他引：1  
K. A. Gravois 《Euphytica》1992,64(3):161-165
Summary Increasing grain weight is one means of increasing rice (Oryza sativa L.) grain yields. Selection for increased density of filled grains may offer an approach to increasing rice grain weight. Before rice breeding programs can begin effectively selecting for higher grain density, the nature and amount of the genetic variation present must be evaluated. A Design II mating plant with two sets was constructed using 16 parents. The 16 parents were representative of cultivars and elite breeding material available to breeders of long-grain rice in the southern U.S. The parents and 32 F1 hybrids were evaluated in 1990 at two Arkansas locations: Stuttgart and Marianna. Additive variation was essentially zero for grain density as indicated by nonsignificant general combining ability (GCA) and specific combining ability (SCA) mean squares and a narrowsense heritability estimate –0.04 (±0.07). Increasing rice grain weight through increased grain density would not be feasible in U.S. southern long-grain rice unless new germplasm with higher filled grain densities is introduced. Genetic variation for grain weight was predominately additive and complemented with additive x additive epistatic variation, indicating that selection for increased grain weight could be practiced in segregating generations. The small proportion of epistatic variation to additive variation would not justify delaying selection until epistatic combinations are fixed in the homozygous line. Midparent grain weight means would serve as an adequate indicator of progeny performance for cross appraisal.Abbreviations GCA General Combining Ability - SCA Specific Combining Ability  相似文献   

2.
Summary The efficiency of the honeycomb selection procedure in selecting outstanding genotypes was observed at two interplant distances (d), i.e. d=100 cm, low density, representing noncompetitive conditions and d=15 cm, high density, representing presence of interplant competition. Progress due to selection among the plants grown with and without competition was established by comparison of the plot performance of offspring from selected plants with that of offspring from plants taken at random. The relation between selection intensity and response to selection was observed to detect a possible negative correlation between competing and yielding ability.So far, the results obtained do not yet allow to make a choice between selection of individual plants in presence or in absence of interplant competition. No significant correlation between single plant yield and plot yield was found at any of the two densities. However, response to selection for yield was higher when selecting at low density supporting Fasoulas' preference for selecting single plants in absence of competition. These results must be taken with caution since seed quality and a biassed sample of random plants exerted an important effect on the obtained response to selection.  相似文献   

3.
Summary Ten hexaploid winter triticale lines were grown for two cropping periods at three locations in western Switzerland. Averaged across the six environments, the differences between lines were statistically significant (P=0.05) for grain yield, above-ground biomass, N uptake, grain N yield, nitrogen harvest index, grain N concentration and straw N concentration. There were significant line x environment interactions for all traits. Grain yield and grain N concentration were inversely related (r=–0.74**). Diagrams in which grain yields were plotted against grain N concentration were used to identify lines with a consistently unusual combination of grain yield and grain N concentration. Despite comparable grain yields, Line 3 had a high grain N concentration, while that of Line 7 was low. Line 3 was superior to Line 7 in both N uptake and N harvest index. Averaged across environments and lines, the N harvest index was 0.73 which corresponds to N harvest indices reported for bread wheat in the same region. We considered the feasibility of developing triticale lines which would outperform the best recent ones in N uptake and partitioning. However, we doubted that this would bring about a marked increase in grain N concentration, because, in the long run, the expected genetic progress in grain yield will lead to a dilution of grain protein by grain carbohydrate increments.Abbreviations GNC grain N concentration - GNY grain N yield - GY grain yield - HI above-ground dry matter harvest index - NHI nitrogen harvest index - SNC straw N concentration - TB total above-ground biomass - TPN total plant N  相似文献   

4.
小麦子粒构型性状与粒重的相关性分析   总被引：1，自引：0，他引：1  
对小麦6044和01-35及由这两个材料构建的187个重组自交系群体的子粒构型性状(粒长、粒宽、粒厚、粒形等)和产量相关性状千粒重进行了相关性分析。结果表明,千粒重与粒长、粒宽、粒厚都有较高的相关性,其中与粒厚相关性最高(相关系数r=0.854**),表明粒厚对粒重的影响最大,粒宽与粒长次之。子粒构型性状之间也有一定的相关性,其中粒宽与粒厚的相关性最大(r=0.775**),其次为粒长/粒宽与粒长/粒厚(r=0.754**),而粒厚与粒长/粒厚表现为极显著负相关(r=-0.612**),说明粒形主要受粒长和粒厚的影响。  相似文献   

5.
Summary In a study designed to investigate the nature and basis of the relationships between grain yield (GY) and grain protein concentration (GBC) in common wheat, 11 populations, including 4 homozygous-homogeneous and 7 heterozygous-heterogeneous populations, were evaluated in a space planted and a solid seeded trial. Analysis of yield and protein data from each population revealed that phenotypic and environmental correlations between GY and GPC were negative and highly significant, whereas genetic correlation was significant in only one of 7 segregating populations studied. These results suggested that the inverse relationships between GY and GPC, although phenotypically real, were not caused by genetic factors. It would appear that environmental factors, source-sink interactions, and dilution of protein by non-protein compounds were the major agents that caused undesirable associations between the two traits.Contribution No. of the Department of Plant Science, University of Alberta, Edmonton, Alberta, Canada T6G2P5  相似文献   

6.
Phytate (inositol-hexa-phosphate) has an important role in plants but it also may have anti-nutritional properties in animals and humans. While there is debate within the plant breeding and nutrition communities regarding an optimum level in grain, there appears to be little information at the molecular level for the genetics of this trait, and its association with important trace elements, in particular, Fe and Zn. In this preliminary study, quantitative trait loci (QTL) for grain phytates, Zn and Fe in glasshouse-grown rice lines from an IR64 × Azucena doubled haploid population were identified. Correlations between phytate and essential nutrients were also studied. Transgressive segregation was found for most traits. Phytate and total P concentrations had one QTL in common located on chromosome five with the (high concentration) allele contributed from Azucena. There were significant positive correlations between phytate and inorganic phosphorus (P), total P, Fe, Zn, Cu and Mn concentrations for both grain concentration and content. However, the QTLs of phytate were not located on the same chromosomal regions as those found for Fe, Zn and Mn, suggesting that they were genetically different and thus using molecular markers in breeding and selection would modify the phytate level without affecting grain micronutrient density.  相似文献   

7.
GW2, a grain weight quantitative trait locus (QTL) in rice encodes a ring type E-3 ubiquitin ligase. A single nucleotide deletion at the 346th nucleotide position in the ligase domain of GW2 was earlier reported to result in higher grain weight in rice. The present study aimed at validating the known functional polymorphism and identifying additional natural genetic variation if any, in the region that included the functional domain of GW2 in a set of indica and aromatic genotypes for which ninety three rice genotypes were phenotyped for grain length, grain width and 100 grain weight. A wide range of variation was observed for these traits. PCR amplification and sequencing of GW2 target region revealed absence of insertion/deletion (InDel) at the 346th position which suggested that the genetic variation in grain weight in Basmati and non-Basmati indica genotypes was not explained by this InDel. However, four new single nucleotide polymorphisms (SNPs) were discovered at nucleotide positions 406, 461, 466 and 501 in the fifth exon and one InDel each in second and fourth introns. Only two of these SNPs, at positions 461 and 501 led to amino acid substitutions. A total of 10 haplotypes were constructed based on these four SNPs which could be regrouped into four categories based on their amino acid substitutions. Association genetic analysis of these haplotypes with different grain traits revealed a moderate association with grain width (R2 = 0.18 at P < 0.05). Thirteen haplotypes constructed using both intronic and exonic polymorphisms did not have any association with grain traits.  相似文献   

8.
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9.
Summary Better understanding of the physiological and genetic basis of wheat grain protein will contribute to breeding efforts for this characteristic. This study provides information about plant protein distribution in high and low grain protein winter wheats (Triticum aestivum L.) at different growth stages and its relation to grain protein. Field experiments involved two winter wheats with high grain protein, Redwin and Lancota, and two with low grain protein, Centurk and Brule in two years. Protein content in the head, the upper three leaves, the first and second leaf, and the peduncle were estimated with Near Infrared Reflectance Spectrophotometer (NIR) at five growth stages. High protein cultivars had higher leaf protein at ripe and higher protein content in the heads at most growth stages than low grain protein cultivars. High protein cultivars had lower protein content in the peduncle than low protein cultivars at ripe. Correlation coefficients between plant-part protein and grain protein ranged from 0.48 to 0.87 for the heads, from –0.45 to –0.79 for the peduncle, and from 0.55 to 0.84 for the leaves. A combination of head, peduncle, and first leaf protein at heading was significantly related to grain protein (R2=0.71). Indirect selection for head, peduncle, and first leaf (flag leaf) protein at heading should result in increased grain protein. Recurrent selection for increased grain protein, with parent selectionbefore anthesis and hybridization should be successful.  相似文献   

10.
Ish Kumar  H. L. Sharma 《Euphytica》1982,31(3):815-816
Summary Inheritance of grain threshability was studied in a cross between two indica rice varieties. Hard threshability was found to be completely dominant over easy threshability. The segregation pattern indicated threshability to be monogenically controlled.  相似文献   

11.
Climate change may lead to an increase in both day and night time temperatures in rice (Oryza sativa L) growing regions, but the impact of such temperature increases on yields of Australian rice varieties is not known. We evaluated the biomass and grain yield response of eleven Australian rice varieties including long, medium and short grain types, and the Californian cultivar M205, to heat stress during the reproductive phase and grain filling stages. Heat stress (day/night = 35/25°C) was applied at one of three stages: from panicle exertion to anthesis (PE), from anthesis to 10 days after anthesis (EGF) and from 10–20 days after anthesis (LGF) periods after which the effect on biomass and grain yield was compared to control plants. When heat stress was applied at PE and early grain filling stages, mean grain yield losses across rice varieties were 83% and 53%, respectively, though significant genotype × heat stress treatment interactions were observed. Notably, three varieties—YRM 67, Koshihikari and Opus—appeared to possess greater tolerance to heat stress at these growth stages. A significant genotype × heat stress treatment interaction was also observed in the LGF treatment, where significant yield reductions were only observed in Opus (21% loss) and YRM 67 (25% loss). A lack of effect of heat stress on total grain yield in most varieties at late grain filling appeared to be due to late tiller grain yields which were either unaffected by the heat stress or increased significantly compared to control plants. While genetic variation for tolerance to heat stress across the three growth stages was observed, there was no rice genotype that was consistently tolerant (in terms of yield under stress) across all three heat stress treatments. In the absence of a genotype that showed broad heat stress tolerance during reproductive growth, we suggest screening of a wider pool of more diverse rice germplasm is warranted.  相似文献   

12.
Grain weight and grain length are the most stable components of rice yield and important indicators of consumer preference. Considering the potentials of wild rice and to enhance the rice yields to meet the increasing demands, 185 Backcross Inbred Lines (BILs) in the background of O. sativa ssp. indica cv. PR114, including 63 rufi-BILs derived from O. rufipogon IRGC104433 and 122 glumae-BILs from O. glumaepatula IRGC104387 were evaluated for mapping QTLs for yield and yield component traits using Genotyping by Sequencing (GBS). Phenotypic evaluation of BILs in three seasons spanning two locations revealed significant differences compared with recurrent parent. BILs which did not show significant differences for any trait under investigation, or similar based on pedigree, were excluded from GBS. Some glumae-BILs had to be excluded from mapping QTLs due to less sequence information. A custom designed approach for GBS data analysis identified 3322 informative SNPs in 55 rufi-BILs and 3437 informative SNPs in 79 glumae-BILs. QTL mapping identified one QTL for thousand grain weight (qtgw5.1), two for grain width (qgw5.1, qgw5.2) and one for grain length (qgl7.1) in rufi-BILs. In the glumae-BILs, three QTL for thousand grain weight (qtgw2.1, qtgw3.1, qtgw6.1) and two for grain length (qgl3.1, qgl7.1) were identified. Most of the grain weight and width QTL showed positive additive effect contributed by wild species allele, whereas the grain length QTL showed positive additive effect contributed by recurrent parent allele. Based on their physical position, none of the QTLs were found similar to previously cloned QTLs. QTLs for grain traits identified from low yielding wild relatives of rice reveals their significance in improving further the rice yields and widen the genetic base of cultivated rice.  相似文献   

13.
M. Iqbal    A. Navabi    D. F. Salmon    R.-C. Yang    D. Spaner 《Plant Breeding》2007,126(3):244-250
High grain yield and grain protein content, and early maturity are important traits in global bread wheat ( Triticum aestivum L.)-breeding programmes. Improving these three traits simultaneously is difficult due to the negative association between grain yield and grain protein content and the positive association between maturity and grain yield. We investigated the genetic relationship between maturity, grain yield and grain protein content in a population of 130 early maturing spring wheat lines in a high latitude (52–53°N) wheat-growing region of Canada. Grain protein content exhibited negative genetic correlation with maturity (−0.87), grain fill duration (−0.78), grain fill rate (−0.49), grain yield (−0.93) and harvest index (−0.71). Grain yield exhibited positive genetic correlation with maturity (0.69), rate (0.78) and duration (0.49) of grain fill, and harvest index (0.55). Despite the positive association between maturity and grain yield, and negative association between grain yield and grain protein content, higher yielding lines with medium maturity and higher grain protein content were identified. Broad-sense heritabilities were low (<0.40) for rate and duration of grain fill, grain protein content, spike per m2, grains per spike, harvest index and grain yield, and medium to high (>0.40) for grain weight, days to anthesis and maturity, and plant height. Selection for longer preanthesis and shorter grain fill periods may help circumvent the negative association between grain yield and grain protein content. Selection for shorter grain fill periods and higher grain fill rate may be a useful strategy for developing early maturing cultivars with acceptable grain yields in northern wheat-growing regions.  相似文献   

14.
The relationship between grain protein concentration and grain yield in different cultivars of winter wheat was examined in a series of field experiments carried out over three years, in which 13, 12 and 8 cultivars were studied in each year, respectively. The plants were grown at sites located in Shropshire, west-central England, in years 1 and 2, and at three other locations in eastern England in year 3. Above ground plant samples were collected at an thesis and again at maturity, when they were separated into grain and straw, and analysed for dry matter and N content. Analysis of residuals from regression of grain protein concentration on grain yield (grain protein deviation, GPD) showed that some cultivars had a higher grain protein concentration than was predicted from grain yield alone. It was deduced that the capacity to accumulate a higher grain protein concentration than predicted from grain yield is under genetic control and thus may be improved through breeding. Other factors (weight of N accumulated in the biomass at anthesis, weight of N accumulated in the biomass between anthesis and maturity and the concentration of N remaining in the straw at maturity) were added step-wise into the regression to enable statistical analysis of their relative contributions to grain protein. High GPD may be achieved through increased N accumulation after anthesis, combined with efficient re-translocation of vegetative N reserves. The use of GPD provides a selection criteria in wheat breeding programs to screen for increased grain protein concentration without a concurrent grain yield reduction. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

15.
Grain yield and protein content are traits of major importance in wheat breeding, but their combination is challenging due to a tight negative correlation. Protein yield and grain protein deviation have been proposed as selection criteria to simultaneously improve both traits. Sedimentation volume is an indicator of protein quality, which plays an important role for bread‐making quality in wheat. All these traits have been investigated in our study with 135 parental inbred lines, their 1,604 hybrids and 10 commercial check varieties evaluated at five environments. The focus of our study was to investigate the usefulness of the grain protein deviation and to define a bivariate model for calculating the grain protein deviation. Further, we compared line and hybrid wheat for grain yield and quality‐related parameters such as protein content and sedimentation volume. The grain protein deviation determined with a bivariate model delivered robust estimates of variance components and enabled a balanced selection of genotypes with improved protein content and grain yield across different quality classes. Although heterosis for protein content and sedimentation volume was negative, hybrids had a higher grain protein deviation as well as higher grain yield at a given sedimentation volume or a given protein content than line varieties.  相似文献   

16.
Monogenic inheritance and linkage were established on the basis of F1 observations and analysis of 13,498 plants in 42 crosses for leaf colour, 7046 plants in 27 crosses for plant pubescence, 1926 plants in 8 crosses for number of leaflets per leaf, and 3182 plants in 12 crosses for plant height under field conditions. Normal green colour of foliage was found to be dominant over light green, pubescent plant over glabrous, high number of leaflets per leaf over low number of leaflets, and tall plant over dwarf. Linkage was estimated from joint segregation analysis, taking two characters at a time in all possible combinations as significant χ2 values were recorded for these genes. Gene symbols Gl, Pub, Ph, and Hl are proposed for these four traits, respectively. The genes are arranged in the order of Ph-Gl-Pub-Hl with the map distances of 21.1, 28.9, and 17.5 cM between them. This short sequence of four linked genes spanning over 37.2 cM has been called Linkage Group 2 of lentil.  相似文献   

17.
The objective of this study was to examine the effect of selection using three indirect tests for grain quality on grain yield and dough, and baking properties, measured as alveograph strength, alveograph tenacity/extensibility ratio and loaf volume. The three tests were flour protein content, flour sedimentation and high molecular weight glutenin subunits. Of the indirect tests used for grain quality, sodium dodecyl sulphate (SDS)‐sedimentation allowed the highest intensity of selection for a combined trait index of the target grain quality and grain yield characteristics. The top 48% of the material could be retained on the basis of SDS‐sedimentation, resulting in retention of atleast two‐thirds of the top 10% of genotypes for the combined trait index. Flour protein percentage, a weighted high molecular weight glutenin index and an index combining all the indirect tests—flour protein, SDS‐sedimentation and high molecular weight glutenins—gave selection intensities of 61%, 64% and 55%, respectively, for the combined trait index. If the objective of selection is dough strength alone, then a weighted index of all indirect traits (flour protein, SDS‐sedimentation and high molecular weight glutenins) provided the highest selection intensity (26%). Other selection intensities for individual target traits were 24% for the prediction of loaf volume from flour protein, 40% for the prediction of tenacity/ extensibility ratio using SDS‐sedimentation and 68% for the prediction of grain yield using SDS‐sedimentation.  相似文献   

18.
Richard N. Strange 《Euphytica》2006,147(1-2):49-65
Summary Grain legumes, in common with all other plants, are subject to biotic constraints of which pathogens form an important group. They are variable in type, number, space and time and, most insidiously, in genetic constitution. Consequently, resistance in the plant to a given pathogen may be quickly nullified by genetic alteration of the pathogen, particularly where this is conferred by a single resistance gene. The products of such resistance genes usually recognise, directly or indirectly, a component of the pathogen, which is encoded by a corresponding avirulence gene. Thus resistance and avirulence genes are specific and complementary and the arrangement is referred to as a gene-for-gene relationship. It follows that alteration of the avirulence gene of the pathogen to give a product that is no longer recognised by the product of the resistance gene of the plant gives rise to a susceptible reaction. A possible solution to this problem is to pyramid several resistance genes, a procedure now facilitated by the techniques of genetic modification. In other interactions genes that reduce susceptibility rather than confer complete resistance have been found and in some cases the loci (quantitative trait loci) responsible have been mapped to specific regions of particular chromosomes. The mechanisms by which these genes limit the virulence of the pathogen are generally unknown. However, by gaining an understanding of the fundamental properties of a pathogen that are necessary for pathogenicity or virulence it may be possible to counteract them. Candidates for such properties are toxins, enzymes and mechanisms that interfere with constitutive or active defence of the plant. Reciprocally, understanding the properties of the plant that confer susceptibility may allow selection of germplasm that lacks such properties. Among the candidates here are germination stimulants of pathogen propagules and signals that promote the formation of infection structures.  相似文献   

19.
QTL analysis for grain weight in common wheat   总被引：6，自引：0，他引：6  
Quantitative trait loci (QTL) analysis for grain weight (GW = 1000 grain weight) in common wheat was conducted using a set of 100 recombinant inbred lines (RILs) derived from a cross ‘Rye Selection 111 (high GW) × Chinese Spring (low GW)’. The RILs and their two parental genotypes were evaluated for GW in six different environments (three locations × two years). Genotyping of RILs was carried out using 449 (30 SSRs, 299 AFLP and 120 SAMPL) polymorphic markers. Using the genotyping data of RILs, framework linkage maps were prepared for three chromosomes (1A, 2B, 7A), which were earlier identified by us to carry important/major genes for GW following monosomic analysis. QTL analysis for GW was conducted following genome-wide single marker regression analysis (SMA) and composite interval mapping (CIM) using molecular maps for the three chromosomes. Following SMA, 12 markers showed associations with GW, individual markers explaining 6.57% to 10.76% PV (phenotypic variation) for GW in individual environments. The high grain weight parent, Rye Selection111, which is an agronomically superior genotype, contributed favourable alleles for GW at six of the 12 marker loci identified through SMA. The CIM identified two stable and definitive QTLs, one each on chromosome arms 2BS and 7AS, which were also identified through SMA, and a third suggestive QTL on 1AS. These QTLs explained 9.06% to 19.85% PV for GW in different environments. The QTL for GW on 7AS is co-located with a QTL for heading date suggesting the occurrence of a QTL having a positive pleiotropic effect on the two traits. Some of the markers identified during the present study may prove useful for marker-assisted selection, while breeding for high GW in common wheat.  相似文献   

20.
Inheritance of long grain rice amylograph viscosity characteristics   总被引：19，自引：0，他引：19  
Southern United States long grain rice (Oryza sativa L.) is a unique market type characterized by intermediate amylose content, gelatinization temperature, and amylograph viscosity profile characteristics. Rice breeders sometimes use long grain germplasm with differing amylograph viscosity profiles. The inheritance of rice amylograph viscosity profiles has not been ascertained and, thus, was the objective of this study. A six parent diallel (parents plus F1 hybrids) was evaluated at Stuttgart, AR during 1994 and 1995. In 1994, 65 F2 plants from the ‘L-202’ × ‘Newrex’ and L-202 × ‘Katy’ crosses were space planted, and in 1995, the 65 F2:3 lines were planted as hill plots. The inheritance of amylograph viscosity profiles appeared to be controlled by a single locus with genes with additive effects. The results of the diallel analysis also support control by a single locus with genes with additive effects because GCA effects were significant and SCA effects nonsignificant for peak, hot paste, and cool paste viscosities. Intermediate amylose content and intermediate amylograph viscosity profiles were strongly correlated. Selection first for intermediate amylose content followed by reselection for intermediate hot paste viscosities would identify long grain genotypes with southern United States long grain cooking quality in progeny from crosses between southern United States long grain rice genotypes and softer cooking long grain genotypes. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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