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111.
True-to-type clonal fidelity is one of the most important pre-requisites in micropropagation of crop species. Genetic fidelity of in vitro raised 45 plants of gerbera (Gerbera jamesonii Bolus) derived from three different explants, viz., capitulum, leaf and shoot tips, was assessed by 32 ISSR markers, for their genetic stability. Out of 32 ISSR markers, 15 markers produced clear, distinct and scorable bands with an average of 5.47 bands per marker. The markers designed from AG motif amplified more number of bands. The markers anchored at 3′ ends produced high number of consistent bands than unanchored markers. Fifteen ISSR markers generated a total of 3773 bands, out of which 3770 were monomorphic among all the clones. The Jaccard's similarity coefficient revealed that out of 45 clones derived from different explants, 44 were grouped into a single large cluster alongwith the mother plant with a similarity coefficient value of 1.00, whereas one clone (C38) remained ungrouped. The clones derived from capitulum and shoot tip explants did not show any genetic variation, whereas, one of the leaf-derived clones exhibited some degree of variation. 相似文献
112.
Andrzej Pedryc Szabolcs Ruthner Rita Hermán Boris Krska Attila Hegedűs Júlia Halász 《Scientia Horticulturae》2009
Eight polymorphic simple sequence repeat (SSR) markers located in the G1 linkage group of apricot (Prunus armeniaca L.) were previously developed and evaluated in a small set of cultivars. Those primers were used for studying variability in 77 apricot cultivars belonging to five different geographical groups, such as Chinese, Asian (Irano-Caucasian and Central Asian), North American, Mediterranean and Western European as well as Middle European cultivars. Six of the markers were polymorphic and revealed a total of 71 alleles ranging from 5 (aprigms11) to 20 (aprigms1) alleles per locus with a mean value of 11.83 alleles per locus. In conclusion, the SSR loci located in the G1 linkage group show a level of polymorphism which is similar to loci dispersed throughout the entire genome. The total number of alleles and the number of unique alleles were the highest in Chinese apricots and the lowest in Middle European cultivars. Heterozygosity also showed a decrease from Asia and China to Middle Europe. No association could have been observed between any SSR markers tested and plum pox virus (PPV) resistant phenotype of cultivars. PPV resistant cultivars did not form a separate clade on the dendrogram obtained by UPGMA cluster analysis. Middle European and Chinese cultivars formed separate clusters while other genotypes formed smaller multiple sub-groups or scattered among different clusters. Our results support previous hypotheses on the origin of PPV resistance in North American apricots. The allele data was also presented in a form that allowed the easy observation of allele frequencies in each geographical group at each locus. Using this data field, differences and similarities between cultivar groups can be easily assessed. The analysis demonstrated the links between the North American and Mediterranean apricot germplasm and confirmed that the Chinese and Eastern European cultivars are distantly related. 相似文献
113.
Tradable biodiversity credit systems provide flexible means to resolve conflicts between development and conservation land-use
options for habitats occupied by threatened or endangered species. We describe an approach to incorporate the influence of
habitat fragmentation into the conservation value of tradable credits. Habitat fragmentation decreases gene flow, increases
rates of genetic drift and inbreeding, and increases probabilities of patch extinction. Importantly, tradable credit systems
will change the level of fragmentation over time for small and/or declining populations. We apply landscape equivalency analysis
(LEA), a generalizable, landscape-scale accounting system that assigns conservation value to habitat patches based on patch
contributions to abundance and genetic variance at landscape scales. By evaluating habitat trades using two models that vary
the relationship between dispersal behaviors and landscape patterns, we show that LEA provides a novel method for limiting
access to habitat at the landscape-scale, recognizing that the appropriate amount of migration needed to supplement patch
recruitment and to offset drift and inbreeding will vary as landscape pattern changes over time. We also found that decisions
based on probabilities of persistence alone would ignore changes in migration, genetic drift, and patch extinction that result
from habitat trades. The general principle of LEA is that habitat patches traded should make at least equivalent contributions
to rates of recruitment and migration estimated at a landscape scale. Traditional approaches for assessing the “take” and
“jeopardy” standards under the Endangered Species Act based on changes in abundance and probability of persistence may be
inadequate to prevent trades that increase fragmentation. 相似文献
114.
115.
枇杷种质资源枝梢与叶片性状多样性分析 总被引:1,自引:0,他引:1
对国家果树种质福州枇杷圃内不同来源地的240份枇杷种质资源的枝梢与叶片主要性状进行鉴定和评价,结果表明:枇杷的中心枝长度、中心枝粗度、侧枝长度、侧枝粗度、叶片长度和叶片宽度都存在丰富的多样性;性状相关性分析显示,枇杷中心枝长度和粗度之间、侧枝长度和粗度之间、叶片长度和宽度之间存在极显著的相关性;国外枇杷种质的中心枝和侧枝总体水平比国内的细小,叶片长、宽度则均比国内的大;栽培种在表型特征上表现为枝长叶大,其中心枝长度、中心枝粗度、侧枝长度、侧枝粗度、叶片长度和叶片宽度均大于野生种和野生近缘种;红肉和白肉枇杷的中心枝长度、中心枝粗度、侧枝长度、侧枝粗度、叶片长度和叶片宽度差异都不显著。 相似文献
116.
117.
118.
119.
菠萝蜜遗传多样性的ISSR分析 总被引:3,自引:0,他引:3
用ISSR标记方法对76份菠萝蜜(Artocarpus heterophyllus Lam.)种质资源DNA的遗传多样性进行了检测,24个引物共检测到477条带,其中427条具多态性(占89.52%),平均PIC为0.23,24个引物能把76份种质完全区分开来。遗传距离分析结果显示供试种质的遗传多样性较低,在DNA水平上的遗传相似系数为0.626~0.945,平均为0.775。聚类分析表明,76份菠萝蜜材料在遗传距离系数为0.752处可分为4大类,其中热带植物园的种质WJ2和GSYWJ1与其他种质的遗传距离相对较大,干胞和湿类型不能独立聚类。另外各地区的种质与雷州半岛种质明显分开聚类,而雷州半岛各地区的种质混杂聚类在一起,不能按地区单独聚类。 相似文献
120.
K. Das Mahapatra B. Gjerde P.K. Sahoo J.N. Saha A. Barat M. Sahoo B.R. Mohanty J.
degrd M. Rye R. Salte 《Aquaculture (Amsterdam, Netherlands)》2008,279(1-4):29-34
A challenge test against Aeromonas hydrophila was conducted using 2062 rohu carp (Labeo rohita) fingerlings obtained from 52 dams and 87 sires (87 full-sib families) of two year-classes (2003 and 2004). Attempts to establish a cohabitant challenge model were not successful. Therefore, fish were challenged by intraperitoneal injection with A. hydrophila in two replicate tanks per year-class, and dead fish were collected hourly. The mortality reached its peak at 16–22 h after challenge and had almost completely stopped after 58 h. The test was terminated after 382 h at which the average survival was 43.9 and 48.9% in the two 2003 year-class tanks, and 77.1 and 35.8% in the two 2004 year-class tanks. Heritability estimates for survival were obtained from sire and dam threshold models (THR) and sire and dam linear repeatability models (LINR). For both types of models the heritability estimates based on data from single tanks were not consistent. For both year-classes, data from one of the two challenged tanks demonstrated significant additive genetic variation in survival during the A. hydrophila infection, whereas the heritability estimates were not significantly different from zero for the other tank. Further, genetic correlation between survivals in the two replicate tanks in each year-class was not significantly different from zero. The differential results from the replicate tanks demonstrate that additional challenge test experiments are needed before firm conclusions can be drawn about the magnitude of additive genetic variation for survival to aeromonasis in rohu carp. A cohabitant challenge model that allows the testing of important defence mechanisms in the skin and mucous membranes of the fish might have been more appropriate. To establish a valid cohabitant challenge model for rohu carp should be given high priority. 相似文献