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991.
Karim Sorkheh Behrouz Shiran T. M. Gradziel B. K. Epperson Pedro Martínez-Gómez E. Asadi 《Euphytica》2007,156(3):327-344
Amplified fragment length polymorphism (AFLP) analysis is a rapid and efficient method for producing DNA fingerprints and
molecular characterization. Our objectives were to: estimate genetic similarities (GS), marker indices, and polymorphic information
contents (PICs) for AFLP markers in almond cultivars; assess the genetic diversity of almond cultivars and wild species, using
GS estimated from AFLP fingerprints and molecular characterization; and facilitate the use of markers in inter-specific introgression
and cultivar improvement. The genetic diversity of 45 almond cultivars from Iran, Europe, and America, were studied assaying
19 primer combinations. In addition, several agronomic traits were evaluated, including flowering and maturity times, self-incompatibility,
and kernel and fruit properties. Out of the 813 polymerase chain reaction fragments that were scored, 781 (96.23%) were polymorphic.
GS ranged from 0.5 to 0.96, marker indices ranged from 51.37 to 78.79, and PICs ranged from 0.56 to 0.86. Results allowed
the unique molecular identification of all assayed genotypes. However, the correlation between genetic similarity clustering
as based on AFLP and clustering for agronomic traits was low. Cluster analysis based on AFLP data clearly differentiated the
genotypes and wild species according to their origin and pedigree, whereas, cluster analysis based on agronomic data differentiated
according the pomological characterization. Our results showed the great genetic diversity of the almond cultivars and their
interest for almond breeding. 相似文献
992.
No information is available on the effects of different biomass yield environments on selection efficiency in switchgrass
(Panicum virgatum L.) breeding improvement. This study was conducted to assess the effects of high- and low-biomass yield environments (HYE
and LYE, respectively) on recurrent selection for general combining ability (RSGCA) in a lowland population of switchgrass
(NL-94). The top 14 of 65 NL-94 C0 parent plants were selected based on biomass yield of half-sib (HS) progeny tested for one post-establishment year under HYE
and LYE conditions. Nine of the 14 C0 parent plants were the same based on HS performance under HYE and LYE. Selected plants were intercrossed to produce NL-94
HYE and NL-94 LYE C1 populations. One hundred and twenty-five HS C1 progeny families (60 NL-94 HYE and 65 NL-94 LYE) were evaluated for biomass yield for 3 years (2002–2004) under HYE and LYE
conditions. The HYE produced about 2.5 times higher biomass yields than the LYE in both C0 and C1 HS progeny tests. Estimated additive genetic variance and predicted gains from selection (ΔG) were high in the C1 populations indicating that RSGCA should achieve higher biomass yields. Mean biomass yields of C1 HS families originating from the LYE protocol were significantly higher than those of families originating from the HYE protocol
in both HYE and LYE performance tests, suggesting greater selection response under LYE in the C0 population. The estimates of narrow-sense heritability (
) and ΔG from the C1 populations indicate that positive response to selection for biomass yield is possible in subsequent cycles of selection
under either HYE or LYE, with a possible small advantage for HYE. 相似文献
993.
从缙恢10/R21的杂种后代中发现了一个抽穗期稳定遗传的迟熟恢复系N91(110~114 d),以早熟不育系金23A(89~94 d)作为杂交和回交亲本,获得的F2和BC1F1群体抽穗期均表现双峰分布,χ2检测表明其抽穗期受一对主基因控制,暂命名为Hd(t)。在400多对SSR引物中筛选出5对在早熟基因池和迟熟基因池中表现差异的引物,进行单株验证,用回交群体进行基因定位,发现位于第7染色体长臂末端的SSR标记RM1364和RM3555与Hd(t)连锁,遗传距离分别为32.7 cM和22.5 cM。在目标区域进一步合成8对SSR引物,将Hd(t)基因定位在RM22143与第7染色体末端之间,与RM22143相距12.9 cM。该结果为Hd(t)基因的精细定位、分子标记辅助育种和基因克隆奠定了基础。 相似文献
994.
Summary Pepino (Solanum muricatum), a vegetatively propagated plant from the Andean region used for its edible fruits, has been identified as a potential crop
for greenhouse cultivation in Mediterranean regions. However, attempts for introducing it have been unsuccessful, either because
of the low yield, poor fruit quality, or both. Screening of germplasm under Mediterranean conditions showed that sources of
variation for high yield existed in the cultivated genepool and that wild species S. caripense and S. tabanoense could contribute to a considerable improvement of soluble solids content (SSC) of pepino. Progenies obtained after crossing
genetically distant (AFLP-based) parental clones were heterotic for yield, and allowed the selection of clones with an improved
combination of yield and SSC. As a result of this intraspecific programme, two new improved cultivars (‘Turia’ and ‘Valencia’),
which outperform the rest of cultivars available, have been selected for cultivation in Mediterranean conditions. The interspecific
programme involved the selection of clones with high yield and SSC in backcross generations. The results show that introgression
of genes from the wild species can contribute to improve the SSC of pepino. The backcross programme is in an advanced stage
and new cultivars derived from the interspecific crosses are expected to be released in a near future. New prospects for the
future in pepino breeding include the genetic transformation, the establishment of a genetic map, and the use of the genomic
information from related Solanaceae important crops. All the information obtained is illustrative for the breeding for adaptation
of vegetatively propagated crops. 相似文献
995.
Bt基因在不同陆地棉基因型的表达研究 总被引:2,自引:0,他引:2
研究了Bt基因在陆地棉不同遗传背景下的表达差异。结果表明,(1)Bt基因在不同陆地棉基因型中均能充分表达,与常规(非抗虫)棉相比抗虫性极为显著。(2)不同陆地棉基因型品系(种)之间抗虫性比较,有差异且部分品系间达极显著水平。(3)Bt基因在不同陆地棉基因型的表达,前期(对二代棉铃虫的抗性)差异较大;中期(对三代棉铃虫的抗性)差异变小;后期(对四代棉铃虫的抗性)没有显著差异。(4)转Bt基因抗虫棉Bt基因的表达随棉花的生育进程呈逐渐降低趋势,即对二代棉铃虫的抗性>对三代棉铃虫的抗性>对四代棉铃虫的抗性。 相似文献
996.
Cold acclimation of winter and spring peas: carbon partitioning as affected by light intensity 总被引:4,自引:0,他引:4
Virginie Bourion Isabelle Lejeune-Hnaut Nathalie Munier-Jolain Christophe Salon 《European Journal of Agronomy》2003,19(4):535-548
Like most plants, pea (Pisum sativum L.) becomes tolerant to frost if it is first exposed to low non-freezing temperatures, a process known as cold acclimation. Cold acclimation is a complex process involving many physiological and metabolic changes. Two spring dry peas, two winter dry peas and one winter forage line were exposed to cold temperature in a controlled environment in two experiments, one using low light intensity and the other regular light intensity. Plants were harvested throughout the experiment and dry matter accumulation, water content, soluble and insoluble sugar concentrations were determined from shoot and root samples. Cold acclimation did not occur when temperatures were low if light intensity was low, even in winter peas. In contrast, with regular light intensity, the winter peas acquired more freezing tolerance than spring peas and a close relationship was found between the soluble sugar concentration of leaves just before the frost and the degree of freezing tolerance obtained by the different genotypes. Relationships between freezing tolerance and carbon partitioning between shoot and roots are discussed. 相似文献
997.
Four years' old micropropagated plants regenerated by enhanced axillary branching from shoot buds of a single genotype of
Robinia pseudoacacia were characterized by RAPDs. Random amplified polymorphic DNA analysis was carried outusing 19 random 10-mer DNA primers
and 286 RAPD bands were examined which showed 30% polymorphism. Similarity indices ranged from 0.86 to 0.96 among different
plants based on RAPD data. The UPGMA dendrogram was constructed based on similarity indices which showed clustering of different
plants into subgroups based on similarity values. Our results suggest that somaclonal DNA sequence variations are present
even when organized cultures such as shoot buds were used as explant for micro-propagation.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
998.
Fusarium head blight (FHB), caused by Fusarium graminearum and Fusarium culmorum, is a devastating disease in cereals. This study was undertaken to estimate progeny means and variances in each of five winter triticale and winter wheat crosses using unselected F2−derived lines in F4 or F5 generation bulked at harvest of the previous generation. Fifty (triticale) and 95 (wheat) progeny per cross were inoculated in two (triticale) or three (wheat) field environments. FHB rating was assessed on a whole-plot basis. Mean disease severities of the parents ranged from 2.3 to 6.4 in triticale and from 3.1 to 6.5 in wheat on a 1-to-9 scale (1 = symptomless, 9 = 100% infected). The midparent values generally resembled the means of their derived progeny. Significant (P < 0.01) genotypic variance was detected within each cross, but genotype × environment interaction and error variances were also high for both crops. Medium to high entry-mean heritabilities (0.6–0.8) underline the feasibility of selecting F2-derived bulks on a plot basis in several environments. Phenotypic correlation of FHB resistance between generation F2:4 and F2:5 was r = 0.87 (P < 0.01) tested across 150 wheat bulks at two locations. Our estimates of selection gain are encouraging for breeders to improve FHB resistance in triticale and wheat by recurrent selection within adapted materials. 相似文献
999.
SUN Qian ZOU Mei-Ling ZHANG Chen-Ji JIANG Si-Rong Eder Jorge de Oliveira ZHANG Sheng-Kui XIA Zhi-Qiang WANG Wen-Quan LI You-Zhi 《作物学报》1962,47(1):42-49
As a typical tropical crop, cassava (Manihot esculenta Crantz) has the characteristics of drought resistance, barren resistance, high biomass and so on. In addition to being used for food and forage, it can also be used for production, processing and starch extraction. Due to highly heterozygous cassava genome, breeding is more difficult. Enriching the genetic diversity of cassava germplasm, comprehensively evaluating its genetic background and traits, and discovering superior alleles that control excellent traits are of great significance for cassava breeding in the future. In order to analyze the genetic diversity, genetic relationship and population structure of cassava germplasm in Brazil, 7946 SNPs and 1997 InDels molecular markers were used. Population structure analysis was performed by ADMIXTURE software, and principal component analysis was performed by GCTA software. Brazilian cassava was divided into nine subgroups, and was roughly consistent with the results of cluster analysis using PHYLIP. Among them, subgroup 1, subgroup 2, subgroup 4, subgroup 6, and subgroup 8 could be clustered together respectively, while the samples of other subgroups could be roughly clustered, and there was a certain cross between the samples. The genetic diversity of cassava germplasm in Brazil (0.274) was higher than the genetic diversity level of cassava germplasm in China and Nigeria. Subgroup 5 of Brazil cassava had a relatively high genetic diversity (0.29). The genetic differentiation of subgroups was low (the genetic differentiation vary from 0.03 to 0.15), but higher than domestic cassava germplasm. The genetic distance between cassava accessions varied from 0.084 to 0.297, with the average of 0.228. The results of this study can provide a basis for subsequent association analysis to identify great alleles and introduction. 相似文献
1000.
Summary Cultivated almonds (Prunus dulcis (Miller) D.A. Webb) in Morocco are still propagated from seeds by farmers to overcome transplant failure of grafted trees. Almond collections in southern Morocco conducted since 1975 have resulted in the selection of clones planted at 3 experimental stations. Principal component analysis (PCA) was used to compare kernel, nut, leaf, and growth habit characteristics among 67 selected Moroccan clones and 14 introduced cultivars. Clustering of clones from similar countries and collection areas would suggest the existence of different almond populations. The Moroccan clones did not cluster separately from the foreign cultivars. Three Moroccan clones had exceptionally large nuts and kernels while 7 selections had high yield potential due to high spur density. Moroccan selections tended to be characterized by small leaves in comparison to foreign cultivars. No evidence was found to suggest the existence of separate populations within the Moroccan almond germplasm. 相似文献