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1.
Spot blotch, caused by Cochliobolus sativus (Ito and Kurib.) Drechsler ex Dastur, and heat stress are two important stresses of bread wheat (Triticum aestivum L.) causing substantial yield reduction in the warm areas of South Asia. These two stresses put pressure on at least 25 million hectares of wheat areas worldwide. This study was conducted to examine variation in physiological traits and its association with heat and spot blotch. Eleven diverse bread wheat genotypes were evaluated in replicated field trials under spot blotch epidemics and heat stress conditions in 2006 and 2007 at Rampur, Nepal. Canopy temperature depression (CTD), chlorophyll fluorescence (CF), chlorophyll content, percent disease leaf area, yield and yield components were recorded. Heat and spot blotch individually reduced CTD, CF, chlorophyll content, grain yield (GRY), and thousand kernel weight (TKW), with greater reductions recorded under combined stress. Genotypes showing lower GRY or TKW loss due to spot blotch also exhibited lower yield loss due to heat stress or combined heat and disease stress, suggesting an association between tolerance mechanisms to the stresses. The physiological traits chlorophyll content, CF and CTD showed higher correlations with GRY and TKW than with area under disease progress curve (AUDPC) suggesting their potential application in screening for heat and spot blotch tolerant genotypes. Genotypes with lower disease showed the highest values for chlorophyll content, CF and CTD. Our findings provide new information on the relationship of these physiological traits with spot blotch resistance and heat tolerance when examined in the same study. The physiological traits studied have potential application in integrative indirect selection criteria for improving spot botch and heat tolerance in wheat.  相似文献   

2.
Subunits of high molecular weight glutenins strongly influence wheat bread making quality and can be associated with important agronomic traits. Polish winter wheats show a significant quantitative dominance of the null allele over the coding alleles of the Glu-A1 locus. To identify the causes of such skewed distribution, 116 F5 lines obtained from six cross combinations were analyzed for their HMW glutenin subunits and 11 agronomic characteristics, such as plant height and uniformity, leaf blotch and leaf rust resistance, grain yield per plot, number of grains per ear, grain yield per ear, 1000 kernel weight, frost tolerance, total protein content and the SDS-sedimentation value. The SDS-sedimentation value, resistance to leaf blotch and frost tolerance showed statistically significant associations with the status of the Glu-A1 locus. It appears that chromosome 1A with the null allele at Glu-A1 carries a closely linked locus responsible for frost tolerance. With early strong selection for winter hardiness, the null allele of Glu-A1 becomes fixed in advanced breeding materials despite its strong negative impact on the end use quality.  相似文献   

3.
Improving the host genotype is one method of increasing biological nitrogen fixation by Bradyrhizobium in symbiosis with peanut (Arachis hypogaea L.), but host-strain interactions also must be considered. The objective of this study was to estimate the effect of Bradyrhizobium strains on the inheritance of traits related to nitrogen fixation. Eight parents and the F1 generation of a diallel cross were evaluated in symbiosis with two bacterial strains for combining ability in a factorial arrangement in the greenhouse. The parents represented three taxa of cultivated peanuts. The two Bradyrhizobium strains NC 92 and NC 123 produced different general and specific combining ability, maternal (reciprocal general) effects, and reciprocal specific effects for the host genotypes. With strain NC 92, the peanut cultivars NC 7 and NC Ac 2821 had the best general combining ability for all traits evaluated; while, with strain NC 123, Robut 33-1 exhibited a high general combining ability (GCA) for nitrogenase activity and specific activity. Genotype NC Ac 2821, when inoculated with strain NC 123, had a negative GCA effect for nodule number, while with strain NC 92 this cultivar had the highest GCA effect. The importance of strain selection in evaluating lines in a breeding program is discussed.  相似文献   

4.
江汉平原大豆品系表型分析及综合评价   总被引：1，自引：0，他引：1  
刘歆  杨芳  邓军波  汪嫒嫒  何念  陈艳 《作物杂志》2021,37(5):57-634
种质资源是大豆育种的基础,理论方法是品种选育的关键。以64份大豆品系为材料,采用变异性分析、相关性分析、因子分析和聚类分析等多元分析方法相结合,对大豆品系的10个农艺性状及产量性状进行研究,筛选适宜江汉平原种植的大豆品系,同时探究影响大豆产量的关键因素,为选育优质高产大豆品种提供种质和理论依据。结果表明,大豆品系10个农艺性状的变异系数为4.19%~46.95%,有效分枝数变异系数最大,蛋白质含量变异系数最小;因子分析将10个农艺性状转化为4个主因子,分别为产量构成因子、株高因子、粒重因子和品质因子,累计贡献率为80.067%。由农艺性状与综合得分相关性分析可知,生育期、株高、主茎节数、单株荚数、单株粒数、单株粒重和蛋白质含量7个农艺性状可作为大豆品系综合评价指标。聚类分析将64份大豆品系分成3个类群,类群Ⅰ31份,类群Ⅱ24份,类群Ⅲ 9份,类群Ⅲ大豆品系综合表现较好,适宜在江汉平原种植。  相似文献   

5.
Bacterial wilt of tomato caused by Ralstonia solanacearum species complex (RSSC) causes substantial yield losses in the tropics and subtropics. Disease management options by chemicals are limited, and host resistance is the cheapest and easiest means of control. However, sources of bacterial wilt resistance in tomato are limited. The disease often coincides with higher temperatures in the tropics, and resistance sources that are more heat stable are particularly valuable for breeding of tropically adapted tomato cultivars. The objectives of this study were to identify tomato accessions that demonstrate relatively high bacterial wilt resistance under high temperatures and to identify accessions that may possess QTLs other than Bwr-6 and Bwr-12 (two major disease resistance QTLs against bacterial wilt), which could be exploited in future breeding. Sixty-seven tomato entries reported as bacterial wilt resistant were evaluated in a greenhouse against one strain each of phylotype I (Pss4) and phylotype IIB (Pss1632) of the RSSC (average temperature ≥29°C). Of those, five and 19 were homozygous for Bwr-6 and Bwr-12, respectively, and six were homozygous for both QTLs. Bwr-12 contributed to resistance against phylotype I strain but not against the phylotype II strain. Bwr-6 contributed to resistance against both phylotype strains. Entries with both QTLs as a group performed relatively better against the phylotype I strain. Entry “94T765-24-79”, which lacked Bwr-6 and Bwr-12, demonstrated relatively high resistance against the phylotype II strain and may carry new QTL/s. As new bacterial wilt resistance QTLs are mapped and markers designed, pyramiding multiple bacterial wilt resistance QTLs into new varieties should be straightforward, thereby increasing the chances of obtaining stable resistance.  相似文献   

6.
Spelt wheat (Triticum spelta L.) is an old‐world crop that has attracted increased attention since the 1970s accompanied by a constant increase in spelt production. Our objectives were to (i) study the genetic variability and heritability of important agronomic traits and (ii) examine the correlation among these traits for an efficient design of spelt breeding schemes. To this end, we compared a diversity panel of 150 old and new spelt varieties with current elite‐breeding material. Phenotypic data were recorded at multiple locations for yield, plant height, lodging, heading time, number of spikelets, ear snapping and susceptibility to powdery mildew, brown rust and Septoria tritici blotch. We observed highly significant genetic variances for almost all traits in both germplasm sets. Heritability estimates ranged from 0.23 for Septoria tritici blotch to 0.97 for plant height. A significant correlation between yield and plant height of ?0.56 as well as yield and lodging of ?0.39 was determined but no other correlation of yield with any of the examined traits. Thus, pedigree selection with early generation screenings on plant height and lodging can be recommended for further spelt improvement.  相似文献   

7.
Summary The increasing popularity of organic agriculture and health food products has led to a renewed interest in hulled wheat species such as emmer (Triticum turgidum ssp. dicoccumSchubler). Knowledge on agronomic and quality traits is required for effective and efficient use of germplasm collections in breeding programs. The objective of this study was to estimate agronomic and grain quality traits of emmer wheat cultivated in Italy. A total of 20 emmer accessions consisting of landraces, breeding lines or cultivars selected from landraces and modern cultivars were examined under low input conditions. The study was conducted for three successive years (2002–2004) at one location of Southern Italy (Foggia). The entries were characterized for agronomic and qualitative traits [grain yield (t ha−1), thousand grain weight (g), test weight (kg hl−1), grain protein content (%), HMWG composition, dry gluten content (%), gluten index and yellow index, alveograph indices and Total Organic Matter (TOM) on cooked pasta]. The results showed a large genetic variability for most of the traits measured and, even if most of the accessions showed inferior bread- and pasta-making performance, modern cultivars exhibited improved quality traits with some potential to perform healthy and tasty food.  相似文献   

8.
Spot blotch of wheat (Triticum aestivum L.), caused by Bipolaris sorokiniana (Sacc. in Sorok.) Shoem., is a major disease in South Asia. Popular commercial cultivars have low levels of resistance to spot blotch. Information on the inheritance of spot blotch resistance in wheat is lacking. Field studies were conducted in four wheat crosses, each involving a Chinese hexaploid parent with high levels of resistance and a commercial cultivar with low to intermediate levels of resistance to spot blotch. Data were recorded in the F2, F3 and F4 generations to estimate heritability. Field studies were conducted in three years (1992–94) at Rampur. Nepal, involving 150 lines in each cross. The spot blotch score was recorded as the percentage necrosis and associated chlorosis of the two upper most leaf surface. In the F2 generation three spot blotch readings on the flag leaf were taken whereas in the F3 and F4 generations four readings were recorded at 5-day intervals on the flag and the penultimate leaves. The highest disease score (HDS) and the area under disease progress curve (AUDPC) were analysed. Heritability (h2) estimates for spot blotch resistance were intermediate to high measured in terms of HDS (0.47 < h2 < 0.67) and also AUDPC (0.58 < h2 < 0.77) both in F3 and F4 generations in each of the four crosses. Heritability values were somewhat higher for AUDPC than HDS. There were significant negative correlations (r) of days to heading with HDS (-0.186 < r < -0.515) and AUDPC (-0.218 < r < -0.623). One-hundred kernel weight was significantly negatively correlated to AUDPC (-0.245 < r < -0.454) in all crosses in each generation. The results suggest that selection for resistance to spot blotch could be effective in the segregating populations generated from hexaploid wheat parents having different levels of resistance. Although AUDPC appeared to be a better measure to determine genetic differences for spot blotch in wheat, HDS would be adequate in screening trials for resistance to spot blotch.  相似文献   

9.
Functional markers reduce the risk of false selection in marker-assisted selection (MAS), and recombination between the molecular marker and the gene of interest. The present study was conducted with the objective of combining the important basmati quality traits with resistance to bacterial leaf blight (BLB) by a combination of phenotypic selection and MAS. Screening of 29 recombinants for BLB resistant genes along with aroma (fgr) gene was performed using a suite of different markers. Twenty genotypes were found in homozygous condition for Xa21 and xa13 genes. Restriction digestion analysis with BsrI, gave nine resistant recombinants. Out of nine resistant recombinants, seven were in homozygous and two were in heterozygous conditions. Recombinants viz., IRS 5441-2-21, IRS 5441-2-79, IRS 5441-2-81, IRS 5441-2-85 and IRS 5441-2-91 possessed all the three BLB resistance genes and fgr in the homozygous condition. Recombinants with enhanced resistance to BLB, basmati quality and desirable agronomic traits were identified. This germplasm can be directly developed into commercial varieties or used as immediate potential donors of BLB resistance in basmati breeding programs.  相似文献   

10.
Protein content, yield and 1000-grain weight of healthy and net blotch-diseased plants were studied in a diallel cross programme concerning nine different varieties of barley (Hordeum vulgare L.). F1 hybrids and their parents were grown in the field in two randomized block design experiments each with three replications (three inoculated and three non-inoculated plots). General and specific combining abilities were determined for yield, protein percentage, 1000 grain weight, protein yield, and non-protein yield. A high genetic variability for the traits studied was observed. Non-protein yield and 1000-grain weight decreased significantly in inoculated plants where protein yield was not affected. Significant general and specific combining abilities were observed for all traits. Values for general and specific combining abilities were, in some cases, significantly modified by net blotch of barley. This indicates that attention must be paid to the danger of drawing conclusions in quantitative genetics studies dealing with both diseased and healthy plants.  相似文献   

11.
Natto, a traditional soyfood fermented by Bacillus subtilis (natto), is prepared by steaming/cooking of soaked soybean seeds followed by inoculation with the bacteria and incubation. Natto soybean has increased in popularity due to its nutritional value and health benefits. Thus, the natto soybean market provides additional opportunities for farmers. The development of soybean cultivars with improved natto quality characteristics is crucial for maintaining and increasing the natto soybean market. Good‐quality characteristics of natto are determined by soybean cultivar, processing conditions and bacteria strain. Natto quality evaluation generally determined by sensory panels is time consuming. Therefore, indirect selection for natto quality based on seed traits is preferred. Seed morphological and physiological characteristics and seed compositions play an important role in producing natto of good quality. In this review, we have summarized natto processing conditions, natto quality characteristics, seed traits involved in natto quality and their genetic variation, as well as the genetic diversity in food‐grade soybean germplasms and B. subtilis strains. Information presented will be helpful for natto soybean cultivar development and natto manufacture.  相似文献   

12.
J. Robinson 《Euphytica》1999,110(3):175-180
A half-diallel was made between five six-rowed Nordic spring barleys to study the genetics of resistance to net blotch. Twenty-five doubled-haploid (DH) lines from each cross and the parents were sown in hill plots in Finland in 1997 and 1998. The plots were artificially inoculated with Pyrenophora teres Drechs. f. teres Smedeg. and assessed for resistance to net blotch. There were statistically significant differences in resistance of the five parents to net blotch. General combining ability (GCA) of the parents and specific combining ability (SCA) effects in the progeny were statistically significant in both years, but GCA effects predominated. Evidence for additive epistasis was minimal. Progeny of a particular cross were less resistant to net blotch than the better parent. The most resistant progeny were derived from the cross between the two most resistant parents, Pohto and WW7977, and resistance was governed by at least eleven effective factors. Narrow sense heritability estimates for resistance to net blotch were high during both years (0.84–0.99). It appears that net blotch resistance of progeny from crosses can be largely predicted from reactions of the parents. Quantitative resistance to net blotch can be further advanced by identification and incorporation of superior parents, from a screening such as reported here, into a recurrent selection breeding programme. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

13.
Spot blotch caused by Bipolaris sorokiniana is an important disease in barley worldwide, causing considerable yield losses and reduced grain quality. In order to identify QTL conferring resistance to spot blotch, a highly diverse worldwide barley set comprising 449 accessions was phenotyped for seedling resistance with three isolates (No 31, SH 15 and SB 61) and for adult plant resistance at two locations (Russia and Australia) in two years. Genotyping with the 50 k iSelect barley SNP genotyping chip yielded 33,818 informative markers. Genome-wide association studies (GWAS) using a compressed mixed linear model, including population structure and kinship, revealed 38 significant marker-trait associations (MTA) for spot blotch resistance. The MTA corresponded to two major QTL on chromosomes 1H and 7H and a putative new minor QTL on chromosome 7H explaining between 2.79% and 13.67% of the phenotypic variance. A total of 10 and 14 high-confidence genes were identified in the respective major QTL regions, seven of which have a predicted involvement in pathogen recognition or defence.  相似文献   

14.
A total of 316 doubled haploid lines (DH) of spring wheat were compared with 621 lines selected in a pedigree system (PS) under field conditions in a breeding nursery. The lines originated from 21 crosses and the samples tested represent mean values for variables comprising the main breeding goals such as disease resistance, baking quality, and agronomic traits. In general, the DH lines were later in days to heading and shorter than PS lines of different homozygosity levels. Except for leaf rust (Puccinia recondite), the DHs were more resistant to the artificially infected diseases such as powdery mildew (Erysiphe graminis), stripe rust (Puccinia striiformis), and septoria nodorum blotch (Septoria nodorum). These differences, which were relatively small for practical selection purposes, were probably due to easier and more precise disease assessment of the homozygous DH lines. For quality characters, the DHs had a higher protein level, while the rest of the parameters were similar for both origins. The data analyzed suggest so far that androgentic doubled haploids in spring wheat are very similar to lines selected in a pedigree system in respect to all the agronomic characters tested. However, the DH lines were produced in a much shorter period of time. It is suggested that androgenetic doubled haploids be produced from F1 hybrids and that the well-established bulk method should continue to allow selection bulk method should continue to allow selection for rare recombinants as soon as homozygosity is reached.  相似文献   

15.
Summary The aim of this research was to evaluate the response to phenotypic recurrent selection for four seed quality traits, i.e. protein content, dye binding capacity, tryptophan content, and specific weight, in a modified opaque-2 population of maize (Zea mays L.). Changes in other agronomic traits were also studied. Four selection cycles, using as selection criterion an index constructed from the four seed quality traits, were completed on an individual plant basis. The material from each cycle and from testerosses of each cycle with a homozygous opaque-2 tester was grown for two consecutive years to evaluate the progress due to selection. The results showed that four cycles of recurrent selection induced sizeable variations among cycles for all selected traits. The rate of progress for the four seed quality traits was nearly linear. Further-more, theldata show that improvement in seed-protein related traits had no negative effects on grain yield and kernel weight, when evaluated as the mean performance of testerosses. There was also no appreciable alteration in the other agronomic traits caused by selection for seed quality traits.  相似文献   

16.
G. Oettler  T. Schmid 《Plant Breeding》2000,119(6):487-490
Septoria nodorum leaf and glume blotch is an important disease of triticale (×_Triticosecale Wittm.) and can cause severe losses of grain yield in some regions. Quantitative genetic parameters for resistance were estimated for 2 years in two locations in triticale genotypes artificially inoculated with S. nodorum. The effect of infection was assessed by a visual symptom rating of flag leaves and spikes and by grain yield traits relative to an uninoculated control. The mean ratings of flag leaves and spikes, calculated from two to four ratings, were 2.6 and 3.9, respectively, with a range of six ratings for spikes and over five for flag leaves. Infection caused an 11.5% mean reduction in kernel weight per spike, which was the result of 13.2% lower 1000‐kernel weight. The number of kernels per spike and 50‐ml weight were little affected. For all relative grain yield traits, genotypic variation was small with high genotype‐environment interaction effects and thus moderate to low heritabilities. In contrast, for visual ratings genotypic variation was high, with low interaction effects leading to high heritabilities. Phenotypic correlation between flag leaf and spike ratings was low, indicating independent disease resistance mechanisms. The best association, although still moderate, was obtained between flag leaf rating and relative 1000‐kernel weight. Therefore, visual disease ratings do not satisfactorily assess the effect of Septoria infection on grain yield traits. The reduction in 1000‐kernel and possibly 50‐ml weight are good indicators, provided that multi‐environment tests are conducted.  相似文献   

17.
利用RIL群体创造抗黄曲霉兼抗青枯病的高油花生新种质   总被引：3，自引：0，他引：3  
协同提高抗青枯病花生品种的黄曲霉抗性及含油量是我国花生育种的重要目标之一。利用远杂9102×中花5号杂交后代衍生的重组近交系群体(RIL),通过黄曲霉抗性、青枯病抗性鉴定及含油量测试,表明黄曲霉抗性受2对连锁并具累加作用主基因+加性多基因控制,含油量受2对具抑制作用主基因+加性多基因控制,RIL群体的黄曲霉抗性和含油量变异远远超过双亲的差异,表明它们均具有通过互补产生超亲性状的潜力。获得了抗黄曲霉或抗青枯病的高油后代家系18份,其中抗黄曲霉兼抗青枯病高油新种质1份(J091)。农艺性状和SSR分析结果表明,18份后代材料具丰富的遗传多样性,农艺性状优良,具有重要育种价值。  相似文献   

18.
Summary Twenty nine strains of vegetable amaranth (Amaranthus tricolor were grown for two successive seasons to study different selection parameters for foliage yield and its nine contributing morphological and quality traits. The strains AV-38 (5.06 kg/plot) and AV-31 (5.04 kg/plot) recorded highest foliage yield, followed by AV-30 (4.78 kg/plot) and AV-23 (4.70 kg/plot). The protein and carotenoid content averaged 1.24 ± 0.03 mg/100 mg and 0.83 ± 0.02 mg/g respectively. The leaves of A. tricolor also have considerable quantities of ascorbic acid (112.33 ± 5.00 mg/100 g) and fibre (8.39 ± 0.10%). The mean of individual cuttings for plant height, leaf size, stem diameter, foliage yield, protein, ascorbic acid and fibre content increased with successive cuttings till third cutting and thereafter showed a decline. Genotypic coefficient of variation (GCV) values ranged from 6.80 to 28.25%. However, the fibre content, branches/plant, leaves/plant, plant height and stem diameter showed lowest values of GCV. The values of heritability estimates were high for all the traits in all the cuttings as well as on pooled basis and ranged from 0.89 for branches/plant to 0.98 for foliage yield. Highest expected genetic advance was noticed for ascorbic acid (57.48%), followed by foliage yield (48.30%) and leaf size (29.51%).  相似文献   

19.
Increases in the groat-oil content of oat (Avena sativa L.) increase the energy value of the grain and improve the feasibility of extracting oat oil for use as a vegetable oil. Nine cycles of recurrent selection for greater groat-oil content conducted in a genetically broad-based oat population resulted in dramatic increases in groat-oil content. Our objectives were todetermine if selection for greater groat-oil content affected fatty acid composition, grain quality traits (test weight and seed weight), or agronomic traits (straw yield, biomass, harvest index, heading date, and height). We evaluated 100 random lines from the base (C0) population and each of the nine selection cycle populations in three environments in order to estimate means, genetic variances, heritabilities, and genotypic and phenotypic correlations of grain quality and agronomic traits. We also evaluated 20 random lines from each population to estimate changes in fatty acid contents. Oleate and stearate contents increased over cycles of selection, as did the ratio of unsaturated to saturated fatty acids. Palmitate, linoleate, and linolenate contents and all grain quality and agronomic traits except harvest index decreased over cycles of selection. There was no evidence for reduced genetic variance or heritability in C9 for any trait, but the genotypic and phenotypic correlations between agronomic traits and oil content fluctuated over cycles. Selection for increased groat-oil content improved oil quality but reduced grain quality and agronomic performance of the population. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

20.
The nitrogen (N2)‐fixing bacterial inoculant strain for soybean [Glycine max (L.) Merrill] is not indigenous to South African soils. The interaction between soybean genotype, soil type and inoculant strain, however, has a definite influence on soybean production and compatibility should be optimized. This paper reports a growth chamber study using three different soybean genotypes (Barc‐9, Avuturda and Talana), three Bradyrhizobium japonicum inoculant strains (WB108, WB112 and WB1) and three soil types (Avalon, Arcadia and sand) to evaluate the effectiveness of N2 fixation by different genotype × soil type × inoculant strain combinations, using different measuring parameters. These parameters included nodule fresh mass (NFM), amount of N2 fixed (Pfix), as determined by the ureide method, seed protein content (SPC), average seed mass per plant (SMP) and average foliar N content (FNC). The comparison amongst the three‐way interactions, genotype × soil type × inoculant strain, did not differ significantly for the parameters used. Significant two‐way interactions were soil × inoculant for FNC, Pfix and SMP; soil × genotype for FNC and SMP, and inoculant × genotype for FNC (P < 0.05). The soil × inoculant strain interaction was significant for Pfix (P < 0.05). NFM, Pfix, FNC, SMP and SPC correlated positively with soil pH and negatively with soil clay content and soil NO3– and NH4+ content (P < 0.05). SPC was significantly different (P < 0.05) for soil type, genotype and inoculant strain. Pfix and NFM did not reflect the protein content of the seeds, indicating that nodule evaluation should be used with caution as a N2 fixation parameter. Low soil pH and high mineral N content inhibited N2 fixation. NFM correlated negatively with the clay content of the soil. This finding confirms that soybean production in South Africa can be improved by appropriate selection of genotypes and inoculant strains for their compatibility in different soils.  相似文献   

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