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1.
The objectives of this study were to determine genetics of Al tolerance and whether the Al tolerance observed is governed by the same gene. The lines ‘L‐7903’ and ‘L‐4602’ have been developed through breeding programme as Al‐tolerant lines. These lines showed maximum root regrowth and minimum accumulation of Al and callose as compared to sensitive genotypes (‘BM‐4’ and ‘L‐4147’). Al tolerance in the parents, F1, F2 and backcross generations was estimated using the regrowth of the primary root after staining and scoring of fluorescent signals. The F1 hybrids responded similarly to the tolerant parents, indicating dominance of Al tolerance over sensitivity. The segregation ratios obtained for Al tolerance and sensitivity in the F2 and backcross generations were 3 : 1 and 1 : 1, respectively. Test of allelism confirmed the same gene was conferring Al tolerance in both genotypes (‘L‐7903’ and ‘L‐4602’) as the F1 was also tolerant and no segregation of tolerant : sensitive was recorded. These results indicated that Al tolerance is a monogenic dominant trait that can be easily transferred to agronomic bases through backcross breeding technique.  相似文献   

2.
The inheritance of freezing tolerance in F2‐derived F4 populations from all possible crosses of winter wheat cultivars ‘Kestrel’, ‘Eltan’, ‘Tiber’, ‘Froid’ and germplasm line Oregon Feed Wheat #5 (ORFW) was investigated. When frozen to a temperature equal to the LT50 of the least freezing tolerant parent (ORFW), survival frequency distributions were skewed to greater survival in six of the 10 crosses, however, very few of the progeny from the four crosses to ORFW survived. The inheritance of this freezing sensitivity was investigated with freezing of F2:4 populations from the crosses of ORFW to ‘Eltan’ or ‘Tiber’ to the LT50 of the hardier parent. Very few of the F2:4 populations survived as well as ‘Eltan’ or ‘Tiber’, indicating a small number of strongly dominant genetic factors in ORFW that conditioned freezing sensitivity. Molecular analysis indicated these factors were not spring‐type vernalization alleles.  相似文献   

3.
Aluminum (Al) toxicity is a major limiting factor in acid soils and more adequate genetic tolerance is needed to improve barley adaptation and production in affected regions. To study the inheritance and chromosome location of the Alp gene controlling Al tolerance in ‘Dayton’ barley the primary trisomics of sensitive ‘Shin Ebisu 16’ were crossed to ‘Dayton’. Parental, F1 and F2 seedlings were grown in nutrient solution containing 0.03, 0.06 and 0.09mM Al. and classified for tolerance by haematoxylin staining of the roots. In diploid F2 progeny, Alp was inherited as a single gene, dominant at 0.06mM and recessive at 0.09 mM concentrations, as indicated by the 3:1 and 1:3 (tolerant: sensitive) segregation ratios, respectively. Segregation of the trisomic Frderived F2 seedlings at 0.06mM Al deviated significantly from the 3:1 only for the triplo 4/‘Dayton’ cross. Data for this cross fit the expected trisomic ratios, indicating that the Alp gene is distally located from the centromere on chromosome 4. These results confirm that tolerance is simply inherited, but expression of tolerance is dependent on Al concentration and allele dose.  相似文献   

4.
Summary A preliminary investigation on the inheritance of tolerance to Zn deficiency and the inter-relationship of tolerances to Zn deficiency and alkalinity was made. Three generations of 2 crosses involving parents tolerant (IR20 and IR30) and sensitive (E425) to Zn stress were screened in IRRI concrete beds. One hundred genotypes (varieties and breeding lines) were screened for injury from alkalimity and Zn deficiency. The results of this experiment and earlier mass screening experiments were subjected to association analyses. The results in general indicated that tolerance to different mineral stresses behave nearly independently. The frequency distribution of ratings for 3 generations indicated that the trait tolerance to Zn deficiency is under polygenic control showing continuous variation and transgression in F2. Tolerance seems to be dominant. The heritability varied between crosses.  相似文献   

5.
Cull fruit formation (CFF) in cucumber is a serious problem in subtropical regions. A world collection of cucumber was evaluated in the field for tolerance to CFF over 2 years. Tolerance was identified in landraces collected from the centre of origin (India). Highly significant genotypic effects for tolerance to CFF were observed. The data revealed the presence of genetic variability among cucumber inbreds for tolerance to CFF, which would be useful to develop CFF‐tolerant varieties or hybrids. Genotype‐by‐environment interaction for tolerance to CFF was not detected. Twenty‐one F1 hybrids evaluated for tolerance to CFF indicated the dominance of a low CFF trait which appears to be controlled by many dominant genes. The in breds ‘JL‐1’, ‘JL‐2’ and ‘JL‐11’ would be good choices as parents for developing CFF‐tolerant cucumber hybrids.  相似文献   

6.
S. Kumar 《Plant Breeding》1998,117(2):139-142
The inheritance of resistance to Fusarium wilt (race 2) of chickpea was studied in a set of three crosses, i.e. ‘WR315’בC104’ (resistant × susceptible), ‘WR315’בK850’ (resistant × tolerant) and ‘K850’בGW5/7’ (tolerant × tolerant) in order to investigate the number of genes involved, their complementation and to find out whether resistant segregants are possible in a cross between two tolerant cultivars. Tests of F1, F2 and F3 generations of these crosses under controlled conditions at ICRISAT, Patancheru, India, indicated involvement of three loci (two recessive and one dominant alleles). The homozygous recessive form at the first two loci conferred resistance whereas susceptibility occurred when the first two loci were in the dominant form. A dominant allele at the third locus can complement the dominant alleles at the other two loci to confer tolerance. Occurrence of resistant segregants in a cross between two tolerant cultivars was observed.  相似文献   

7.
Freely nodulating soybean genotypes vary in their phosphorus (P) uptake and P‐use efficiency (PUE) in low‐P soils. Understanding the genetic basis of these genotypes’ performance is essential for effective breeding. To study the inheritance of PUE, we conducted crosses using two high‐PUE genotypes, two moderate‐PUE genotypes and two inefficient‐PUE genotypes, and obtained F1, F2, BC1 and BC2 populations. The inheritance of PUE was evaluated using a randomized complete block design. A generation mean analysis of phenotypic data showed that PUE was heritable, with complex inheritance patterns and the presence of additive, dominance and epistatic gene effects. Seed P, shoot P, root P, P‐incorporation efficiency and PUE were largely quantitatively inherited traits. There were dominance, additive × additive and dominance × dominance gene effects on PUE, grain yield, shoot dry weight, 100‐seed weight, root dry weight and shoot dry matter per unit P for populations grown under low‐P conditions. Dominance effects were generally greater than additive effects on PUE‐related indices. These PUE indices can be used to select P‐efficient soybean genotypes from segregating populations.  相似文献   

8.
Genetics of tolerance to high concentrations of boron in Brassica rapa   总被引：1，自引：0，他引：1  
The inheritance of tolerance to high concentrations of boron in Brassica rapa was studied in F2 and F3 segregating populations. The F1 hybrids were produced from genotypes contrasting in their reaction to boron. The F1 hybrids responded similarly to the tolerant parent indicating that boron tolerance was dominant trait. Segregation patterns for boron tolerance in F2 populations and F3 derived families were established by the measurements of primary root length and tissue boron concentrations. The segregation ratios were explained in terms of two major genes interacting in a dominant epistatic manner to govern tolerance. Evaluation of selected tolerant and susceptible F3 families indicated that tolerant families produced significantly longer primary roots as compared to susceptible families.  相似文献   

9.
Inheritance and genetic linkage analysis of a firm-ripening tomato mutant   总被引：2，自引：0，他引：2  
The tomato cv. ‘Santa Clara’ is widely cultivated among tomato producers in most of the South‐east of Brazil. Recently, some plants of this cultivar were identified with morphological alterations in both vegetative and reproductive organs. These plants showed firm (firme) ripe fruits, slow and delayed ripening. They also had yellow leaves associated with precocious senescence and flowers with pale stigmas. The objective of this work was to determine the genetic model of inheritance for this mutation and to evaluate its effects on shelf life and loss of firmness in mature fruits, as well as analyse the occurrence of genetic relationships between this putative mutant and other pleiotropic mutants. Mutated plants were crossed with the non‐mutant cv. ‘Santa Clara’ and some previously described pleiotropic mutants. Seeds of F1 and F2 generations and backcrosses were obtained for the segregation analysis. Morphological characteristics modified by this mutation are governed by a recessive gene with pleiotropic effects. In addition, the test of allelism showed a lack of genetic complementation between the ‘firme’ mutant and lutescent‐2 mapped on chromosome 10. Fruits of the ‘firme’ mutant had a slower rate of softening compared with the cv. ‘Santa Clara’ and its hybrids. The fruit shelf life of the mutant ‘firme’ was significantly superior to the other genotypes. No maternal effect was detected in either qualitative or quantitative characteristics. Based on the data, the mutation ‘firme’ in the cv. ‘Santa Clara’ is located in the region containing the l‐2 locus, which promoted alterations in ripening and post‐harvest physiology of fruits. The mutation ‘firme’ may represent a new allele of the gene lutescent‐2 or a gene linked to physiological events of fruit ripening.  相似文献   

10.
M. Wissuwa  N. Ae 《Plant Breeding》2001,120(1):43-48
Deficiency in phosphorus (P) can severely limit rice yields. Developing cultivars with tolerance to P deficiency may represent a more sustainable solution than sole reliance on fertilizer application. To assess genotypic variation for tolerance to P deficiency the P uptake of 30 genotypes was measured on P‐deficient soil. Variation for P uptake was high, ranging from 0.6 to 12.9 mg P/plant. Traditional varieties were superior to modern varieties. A major quantitative trait locus for P uptake had previously been identified in a population developed by crossing the modern variety ‘Nipponbare’ with the P deficiency‐tolerant landrace ‘Kasalath’. This quantitative trait locus was transferred to ‘Nipponbare’ by three backcrosses. Under P deficiency this improved line surpassed ‘Nipponbare’ in P uptake by 170% and in grain yield by 250%. These results show that the genotypic variation for tolerance to P deficiency in rice can be used successfully in rice improvement. By combining high P uptake of the donor variety ‘Kasalath’ with a high harvest‐index characteristic of modern varieties it was possible to more than triple the grain yield of ‘Nipponbare’ under P deficiency.  相似文献   

11.
The effects of aluminum on the photosynthetic apparatus were examined in cereals grown in nutrient solutions (pH 4.5) at two Al levels (0 and 148 μM). The chlorophyll fluorescence kinetics results confirmed that the soft wheat ‘BHG’ cultivar has the potential for growth on acid soils while triticale cultivars ‘Niovi’ and ‘Dada’ appeared to be relatively tolerant. The percentage decrease in Fv/Fm of the less tolerant cultivars after Al-treatment indicated a decrease in the efficiency of the primary photochemistry of PS II, while the decrease in the ratio FV/Fosuggested that exposure of the cultivars ‘Dio’ and ‘Appulo E’ to aluminum caused injury to the thylakoid structure. The percentage fluctuations of the ratio Fv/Fmwere shown to correlate very closely with the assessment of injury as evaluated by the relative top fresh weight. Measurements of chlorophyll fluorescence in vivo could be used to monitor injury caused by “Al-stress”, and thus they may serve as a rapid screening test for Al tolerance.  相似文献   

12.
P.K. Singh    G.R. Hughes 《Plant Breeding》2006,125(3):206-210
Tan spot of wheat is caused by the fungus Pyrenophora tritici‐repentis. On susceptible hosts, P. tritici‐repentis induces two phenotypically distinct symptoms, tan necrosis and chlorosis. This fungus produces several toxins that induce tan necrosis and chlorosis symptoms in susceptible cultivars. The objectives of this study were to determine the inheritance of insensitivity to necrosis‐inducing culture filtrate of P. tritici‐repentis, race 2, and to establish the relationship between the host reaction to culture filtrate and spore inoculation with respect to the necrosis component. The F1, F2, and BC1F1 plants and F2:8 lines of five crosses involving resistant wheat genotypes ‘Erik’, ‘Red Chief’, and line 86ISMN 2137 with susceptible cultivars ‘Glenlea’ and ‘Kenyon’ were studied. Plants were spore‐inoculated at the two‐leaf stage. Four days later, the newly emerged uninoculated third leaf was infiltrated with a culture filtrate of isolate Ptr 92–164 (race 2). Reactions to the spore inoculation and the culture filtrate were recorded 8 days after spore inoculation. The segregation observed in the F2 and BC1F1 generations and the F2:8 lines of all crosses indicated that a single recessive gene controlled insensitivity to necrosis caused by culture filtrate. This gene also controlled resistance to necrosis induced by spore inoculation.  相似文献   

13.
Phosphorous (P) deficiency is a major yield limiting factor in rice (Oryza sativa L.) production. The interspecific New Rice for Africa (NERICA) varieties combine general stress tolerance from African cultivated rice (Oryza glaberrima Steud) with characteristics associated with high yield from O. sativa. However, little is known about their ability to tolerate P deficiency. Here, we examined the variation for tolerance to P deficiency among the 18 upland NERICAs and their parents in multi‐year field experiments. The good performance under P deficiency of the O. glaberrima parent CG 14 and some NERICAs suggested that these tolerant NERICAs contain loci associated with P deficiency tolerance inherited from CG 14. Additionally, four QTL clusters for P deficiency tolerance were detected on chromosomes 4, 6 and 11 using F3 lines derived from the cross between the P deficiency tolerant variety NERICA10 and a Japonica‐type sensitive variety ‘Hitomebore’. These QTLs represent the first step in identifying stress tolerance genes from O. glaberrima that could subsequently be used to enhance P deficiency tolerance in O. sativa.  相似文献   

14.
M. H. Rahman   《Plant Breeding》2001,120(3):197-200
The inheritance of petal (flower) colour and seed colour in Brassica rapa was investigated using two creamy‐white flowered, yellow‐seeded yellow sarson (an ecotype from Indian subcontinent) lines, two yellow‐flowered, partially yellow‐seeded Canadian cultivars and one yellow‐flowered, brown‐seeded rapid cycling accession, and their F1, F2, F3 and backcross populations. A joint segregation of these two characters was examined in the F2 population. Petal colour was found to be under monogenic control, where the yellow petal colour gene is dominant over the creamy‐white petal colour gene. The seed colour was found to be under digenic control and the yellow seed colour (due to a transparent coat) genes of yellow sarson are recessive to the brown/partially yellow seed colour genes of the Canadian B. rapa cvs.‘Candle’ and ‘Tobin’. The genes governing the petal colour and seed colour are inherited independently. A distorted segregation for petal colour was found in the backcross populations of yellow sarson × F1 crosses, but not in the reciprocal backcrosses, i.e. F1× yellow sarson. The possible reason is discussed in the light of genetic diversity of the parental genotypes.  相似文献   

15.
Differential tolerance to Fe and Zn deficiencies in wheat germplasm   总被引：3，自引：0，他引：3  
Z. Rengel  V. Römheld 《Euphytica》2000,113(3):219-225
Tolerance to Fe deficiency of wheat genotypes exhibiting differential tolerance to Zn deficiency is not known, even though the relationship between Fe nutrition and differential tolerance of wheat genotypes to Zn deficiency has been hypothesised frequently. In the present experiment, eight Triticum aestivum and two T. turigidum L. conv. durum cultivars were grown in nutrient solution deficient in either Znor Fe. Three indices of tolerance to nutrient deficiency were compared: relative [(-nutrient/+nutrient) × 100] shoot growth, shoot dry weight under nutrient deficiency and relative shoot/root dry weight ratio. Genotypes Aroona, Excalibur, Stilleto and Trident were classified as tolerant to both Zn and Fe deficiency, while durum wheats Durati and Yallaroi were sensitive to Zn deficiency and moderate to sensitive to Fe deficiency. Genotypes Excalibur, Stilleto and Trident come from the same breeding programme and have the common parent (line MEC3 =Sonora64//TZPP/YAQUI54) that could have been the donor of the genes for tolerance to Zn deficiency. When Fe-deficient, all wheat genotypes were severely chlorotic but kept producing shoot and root dry matter at a relatively high rate, making the relationship between the relative shoot growth and the relative leaf chlorophyll content poor. This is the first report of wheat genotypes exhibiting multiple tolerance to Zn and Fe deficiencies. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

16.
Eighteen genotypes of Brassica napus were crossed to a cytoplasmic male sterile (CMS) line of B. napus BO 15 carrying B. tournefortii cytoplasm (‘tour’ cytoplasm). Fourteen genotypes were found to be stable maintainers of the ‘tour’ CMS. Of the remaining four genotypes, GSL-1 and ‘Asahi-natane’ were found to be heterozygous and ‘Mangun’ and ‘Yudal’ were homozygous for the restorer gene. Analysis of the F1 and F2 progenies of (CMS) BO 15 בMangun’ and (CMS) BO 15 בYudal’ showed that fertility restoration is controlled by a single dominant gene. The availability of a number of stable maintainer lines and the simple inheritance pattern of fertility restorer gene makes ‘tour’ CMS a useful system for hybrid seed production in rapeseed.  相似文献   

17.
Summary Aluminum toxicity due to the cation Al+3 is a major factor limiting yields in acid soils. Wide genetic variability to aluminum tolerance is found in oat genotypes. The objectives of this study were to determine the number of genes controlling aluminum tolerance in oats and to verify if any detrimental effects were present of the aluminum tolerance genes on grain yield and grain quality in Al+3free soils. Aluminum tolerance was estimated as the average regrowth of the main root after exposure to toxic levels of Al+3 in a hydroponic solution under controlled conditions. The number of genes controlling that trait was estimated from the distribution of the average root regrowth frequencies in a population of 333 recombinant inbred lines (RIL's) in generations F5:6 and F5:7. The effects on grain yield and grain quality were assessed in a subpopulation of 162 RIL's chosen based on their aluminum tolerance response. Aluminum tolerance in the evaluated population was controlled by one dominant major gene with the tolerant genotypes carying Al a Al a and the sensitive ones al a al a alleles. No detrimental effects of the Al a allele on grain yield or grain quality were detected.Part of the Master of Science dissertation of the first author  相似文献   

18.
Summary Avoidance of drought stress is commonly associated with root system characteristics and root development. The inheritance of root pulling resistance in rice (Oryza sativa L.) was investigated and its relationship with visual field scores for drought tolerance was studied. Transgressive segregation for high root pulling resistance was observed in 3 crosses (high x high, low x high, and intermediate x intermediate). Both dominant and additive genes control the variation. F1 superiority for high root pulling resistance was observed and could be exploited in an F1 hybrid breeding program. F2 distribution curves indicated that plants highly resistant to root pulling can be obtained not only from low x high and high x high crosses, but also from intermediate x intermediate crosses. Root pulling resistance in rice has a low heritability (39 to 47%). Thus, breeding for a high root pulling resistance may best be accomplished by selection based on line means rather than individual plant selection. Field screening showed significant differences in leaf water potential among random F3 lines. F3 lines with higher leaf water potential had better visual scores for drought tolerance. Visual drought tolerance scores were correlated with root pulling resistance. Plants with high root pulling resistance had the ability to maintain higher leaf water potentials under severe drought stress. The usefulness of the root pulling technique in selecting drought tolerant genotypes was confirmed.  相似文献   

19.
Inheritance of Partial Resistance to Net Blotch in Barley   总被引：2，自引：0，他引：2  
Reciprocal crosses were made between 9 different barley genotypes with high genetic variability for net blotch resistance. Parents and 72 F1 plants were used to determine the inheritance of partial resistance to net blotch. Four experiments, one in a growth chamber on seedlings and 3 others in the field on adult plants, were undertaken using a randomised complete block design. An isolate of net blotch from local cultivars was used for inoculation. Non-inoculated plants of one of the field experiments were used for the detached leaf test in petri dishes. Results show that the cultivars ‘Banteng’, and ‘Arrivate’, the Ethiopian line CI 5791, and the Syrian line 79 SIO-10, had a high partial resistance in all experiments. Diallel analysis showed high significant general and specific combining ability when maternal and reciprocal effects were not significant. As the resistance genotypes have a high additive genetic effect, they could be successfully used for breeding purposes.  相似文献   

20.
A. Alizadeh    V. Benetti    A. Sarrafi    G. Barrault    L. Albertini 《Plant Breeding》1994,113(4):323-326
Seven barley genotypes with high genetic variability for resistance to bacterial leaf streak (Xanthomonas campestris pv. hordei) were crossed in diallel fashion to determine the inheritance of resistance to this disease. Two experiments were undertaken in a controlled growth chamber using a complete-block design with four replicates. Each replicate consisted of a row of 20 seedlings per parent or F1 hybrid. An Iranian strain of bacterial leaf streak was used for inoculation of 12-day-old seedlings. Results showed that the cultivars ‘Express’ and ‘Morex’ and the Iranian pure line Iran-3a had a high partial resistance in booth experiments. Diallel analysis showed highly significant general and specific combining abilities. ‘Morex’ and Iran-3a were the best combiners for partial resistance to bacterial leaf streak in barley and could be successfully used for breeding purposes.  相似文献   

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