Heterosis,combining ability and genetic effect,and relationship with genetic distance based on a diallel of hybrids from five diverse <Emphasis Type="Italic">Gossypium barbadense</Emphasis> cotton genotypes

The cultivated tetraploid Gossypium barbadense L. cotton produces superior natural fibers for the textile industry in the world. However, the possibility in utilization of heterosis to further increase its lint yield has not been extensively explored. In this study, two commercial US Pima cotton cultivars and three exotic G. barbadense lines, together with all of their possible hybrids in F₁ and F₂ progeny without reciprocals, were tested for lint yield, yield components, and fiber quality traits in four environments in 2005–2007. With a few exceptions, genotype (G), environment (E), and G × E were all significant or highly significant for all the traits studied. General combining ability (GCA) variances for all the traits in both F₁ and F₂ were also significant, while specific combining ability (SCA) variances were detected only for lint yield, fiber length, and micronaire in both generations and boll weight in F₁. GCA × E was also detected for lint percent, seed index, and fiber length in both F₁ and F₂, and boll weight in F₁, but none of the traits had significant SCA × E. As a group, F₁ and F₂ out-yielded the parent group by 20–40% and 6–10%, respectively. Mid-parent heterosis (MPH) for lint yield in F₁ was generally positive, ranging from ?4.7 to 116.4% with an average of 21.2–48.7%, while lint yield MPH in F₂ ranged from ?23.3 to 69.4% with an average of 6.4–12.4%. However, useful heterosis in lint yield was only detected in the hybrid between the two US commercial cultivars Pima S-7 and DP 340. MPH for other traits was low or not detected. MPH in F₂ was lower than that in F₁ but they were generally positively correlated. The genetic distances (GD) of the parents (based on 467 polymorphic RAPD and AFLP markers) between the five parents was not consistently correlated with MPH and SCA of their hybrids and dominant effects for lint yield and other traits. However, significant and positive correlations between GD of parents and the performance of their hybrids were detected for lint yield, lint percentage, and lint index in both F₁ and F₂ in most of the tests. GD of parents was also correlated with their GCA and additive effects in lint yield, lint percent, lint index, micronaire, plant height, and elongation. The results suggest that the close correlation between GD and hybrid performance per se was mainly due to the existence of GCA and additive effects from parents.     

Diaoyu Dao,Diaoyutai or Senkaku? Creative solutions to a festering dispute in the East China Sea from an ‘Island Studies’ perspective

This paper draws on extensive island examples with a view to offer ‘creative’ solutions to the ongoing dispute over the Diaoyu/Diaoyutai/ Senkaku Islands between China (and Taiwan) and Japan in the East China Sea. In spite of the rhetoric and apparent intractability of island conflicts, there are various examples from the past (and the present) that suggest how island disputes may be decided, and in ‘win–win’ ways, to the satisfaction of the different parties involved. The resolution of island territorial problems can benefit greatly from a critical appreciation of how other small islands, also contested, have had their situation resolved in non‐zero‐sum ways. In such cases, sovereignty has been shared, split/divided or expunged; in other cases, sovereignty disputes have been put aside in order to co‐develop and co‐exploit natural resources. There is also one example of a UNESCO World Heritage Site consisting of a string of small islands and surrounding waters whose management is shared between three countries.     

<Emphasis Type="Italic">LKF</Emphasis>, the locus regulating large grains in the rice cultivar ‘Fusayoshi’, is identical to the loci encoding a serine/threonine protein phosphatase with Kelch motif

The LKF locus, which regulates grain size in the rice cultivar ‘Fusayoshi’ showing large grain, has been mapped to the proximal part of the long arm of chromosome 3. An incomplete dominant allele, Lkf, caused large grain size of Fusayoshi. The structure and function of this locus, however, have not yet been determined. In a similar position to LKF on chromosome 3, two loci, Os03g0407400 (GS3) and LOC_Os03g44500, have been already reported as loci also regulating rice grain size. The objective of the present study was to determine the nucleotide sequences of both Os03g0407400 and LOC_Os03g44500 for different alleles at the LKF locus. Results showed that only one known single nucleotide polymorphism (SNP) in exon 10 of LOC_Os03g44500 was detected between a large-grain allele (Lkf) and a small-grain allele at the LKF locus, whereas no polymorphisms in Os03g0407400. This SNP, visualized using a dCAPS marker, clearly demonstrated nearly complete co-segregation with grain length in an F₂ population segregating the Lkf at LKF. Other large-grain mutant lines with large-grain alleles at the LKF locus, which originated from another cultivar ‘Gimbozu’, also showed the same SNP in exon 10 of LOC_Os03g44500. It was concluded from these results that LKF is identical to LOC_Os03g44500, and the detected SNP in exon 10, at least, which is included in Kelch-like repeat motif, could be essential for expression of the large-grain phenotype.     

Mapping quantitative trait loci for cottonseed oil,protein and gossypol content in a <Emphasis Type="Italic">Gossypium hirsutum</Emphasis> × <Emphasis Type="Italic">Gossypium barbadense</Emphasis> backcross inbred line population

Cotton is one of the most important oil-producing crops and the cottonseed meal provides important protein nutrients as animal feed. However, information on the genetic basis of cottonseed oil and protein contents is lacking. A backcross inbred line (BIL) population from a cross between Gossypium hirsutum as the recurrent parent and G. barbadense was used to identify quantitative trait loci (QTLs) for cottonseed oil, protein, and gossypol contents. The BIL population of 146 lines together with the two parental lines was tested in the same location for three years in China. Based on a genetic map of 392 SSR markers and a total genetic distance of 2,895.2 cM, 17 QTLs on 12 chromosomes for oil content, 22 QTLs on 12 chromosomes for protein content and three QTLs on two chromosomes for gossypol content were detected. Seed oil content was significantly and negatively correlated with seed protein content, which can be explained by eight QTLs for both oil and protein contents co-localized in the same regions but with opposite additive effects. This research represents the first report using a permanent advanced backcross inbred population of an interspecific hybrid population to identify QTLs for seed quality traits in cotton in three environments.     

Inheritance of shelf life and other quality traits of tomato fruit estimated from F<Subscript>1</Subscript>’s,F<Subscript>2</Subscript>’s and backcross generations derived from standard cultivar, <Emphasis Type="Italic">nor</Emphasis> homozygote and wild cherry tomato

A tomato cultivar with high quality fruit and a long shelf life is a main goal in tomato breeding and it would be achieved using wild germplasm. The objective of this work was to explore the inheritance for fruit quality traits, especially fruit shelf life, in three tomato crosses using a standard Argentinean cultivar (Ca, cv ‘Caimanta’), a ripening mutant (nor, homozygous for the nor gene) of Solanum lycopersicum, and a wild cherry type (Ce, LA1385 of S. lycopersicum var. cerasiforme). The wild parent had a shorter fruit shelf life than the mutant genotype but higher than Ca. When the Ce genotype was analyzed in hybrid combination, the F₁ (Ca×Ce) was similar to the wild genotype for shelf life whereas the F₁ (nor × Ce) had a longer shelf life. Both F₁ crosses and backcrosses to the cherry type genotype had significantly lower fruit weight than the cultivated genotypes but higher than the cherry type parent. In the F₂ analysis, it was found that the inheritance underlying quality traits is complex since non allelic interactions were detected. A significant additive genetic variance was found for fruit shelf life as well as for other fruit quality traits in each cross. The genetic parameters analyzed by mean values and variances in parental, F₁ and F₂ and backcross generations indicated that the cross between the normal ripening cultivar and LA1385 of S. lycopersicum var. cerasiforme offers the best possibility to obtain long shelf life tomato genotypes with good fruit quality.     

Mapping a diploid wheat abscisic acid 8′-hydroxylase homologue in the seed dormancy QTL region on chromosome 5A<Superscript>m</Superscript>

In Arabidopsis, two genes of abscisic acid (ABA) 8′-hydroxylase (cytochrome P450 (CYP) 707A1 and A2) have been found to play important roles in seed dormancy through the regulation of ABA content in seeds. In order to examine the role of wheat ABA 8′-hydroxylase gene in seed dormancy, a diploid wheat ABA 8′-hydroxylase gene was cloned that showed high similarity to a barley ABA8′-hydroxylase gene (HvABA8′OH-2), and the cloned gene was designated as TmABA8′OH-2. Using recombinant inbred lines derived from a cross between diploid wheat Triticum boeoticum L. (Tb) and Triticum monococcum L. (Tm), TmABA8′OH-2 has been mapped to near the centromeric region of the long arm of chromosome 5A^m, where the major seed dormancy QTL has been previously found. Comparison of the deduced amino acid sequences of TmABA8′OH-2 between Tb and Tm revealed five amino acid residue substitutions. These amino acid residues have distinctly different characteristics, and one of the substitutions occurs in the highly conserved amino acid residues in CYP707A family, indicating that these substitutions may have effects on the enzyme activities. Moreover, hexaploid wheat TmABA8′OH-2 homologue revealed that the level of its expression during seed development peaks at mid-maturation stage. This resembles the expression pattern of the Arabidopsis CYP707A1, which was shown to control seed dormancy. These results imply a possibility that TmABA8′OH-2 might be involved in seed dormancy, and associated with the QTL on chromosome 5A^m.     

Genetics of Fe,Zn, β-carotene,GPC and yield traits in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) using multi-locus and multi-traits GWAS

The present study was conducted to study the genetic architecture of grain micronutrients (Zn, Fe and β-carotene contents), grain protein content and four yield traits in a spring wheat reference set comprising 246 genotypes. Phenotypic data on these traits recorded at two locations and the genotyping data for 17,937 SNP markers (obtained through outsourcing) were used for genome wide association study, which gave following results after Bonferroni correction using four methods: (1) single locus single trait analysis gave 136 marker-trait associations; (2) multi-locus mixed model gave 587 MTAs; (3) multi-trait mixed model gave 28 MTAs and (4) matrix-variate linear mixed model gave 33 MTAs. As many as 73 epistatic interactions were also detected. Keeping all the results in mind, nine most important MTAs were selected for biofortification. These markers were associated with three traits (GPC, GFeC and GYPP). These MTAs can be used in wheat improvement programs either using marker-assisted recurrent selection or pseudo-backcrossing method.     

Grass pea (<Emphasis Type="Italic">Lathyrus sativus</Emphasis>): Is there a case for further crop improvement?

An ideal legume for resource-poor farmers, grass pea [Lathyrus sativus] is a drought tolerant crop that thrives with minimal external inputs. It is grown on 1 million ha throughout South Asia, mainly as a relay crop after rice. It is also grown extensively in Ethiopia, where it is an important legume for human consumption. Traditionally used for human consumption and as a source of animal feed, this protein-rich legume is favoured for its excellent flavour. There is great potential for an expansion in the utilization of grass pea in drought-prone economies, such as Ethiopia. However, L. sativus produces small quantities of a neurotoxin, β-N-oxalyl –L-α-diaminopropanoic acid (ODAP), which, when consumed alone in large quantities, may cause ‘lathyrism’, an irreversible paralysis of the legs. Lathyrism is a medical condition closely associated with poverty in rural areas. Despite efforts in some countries to discourage production of L. sativus, poor farming communities continue to rely on the crop to supplement their meagre diets. As local land races with high toxin levels generally outperform introduced varieties with lower toxin levels, farmers have little option but to continue to grow their locally-adapted varieties. While there has been some success in breeding grass pea lines with low levels of ODAP, crop improvement programmes are scarce and under-resourced. Facing rising food prices and more frequent natural disasters associated with climate change, we should not neglect the ability of grass pea to provide human and animal feed, under conditions unsuitable for economic production of other legume crops.     

科普须防“失真”，“失声”，“失效”

为了提高对科普工作的重视程度,依靠动员科学家推动科普事业,加强科普资源建设,创新科普活动,针对科普工作和活动经常出现“权威性不够”,“针对性不足”,“实效性不强”等问题。根据长期从事农业科普工作的实践,对科普“失真”,“失声”,“失效”现象产生的原因进行了深入思考,提出了解决这些问题的主要对策建议。     

"种大树"与"大树移植"

由于环境的不断恶化,植树绿化活动在我国城乡风起云涌,形成了热潮。由于“种大树”比栽花种草的生态效益大,所以提倡“种大树”的人越来越多。但目前却有一股“大树移植”风在一些城市劲吹,美其名曰“大树进城”于是十几、二十几厘米胸径的树成千上万地移植进城;更有甚者,将深山老林的古树也挖进城里。笔者认为风不可长。首先应该指出的是“种大树”与“大树移植”是两个不同的概念。虽然“大树移植”也是“种大树”,但提倡“种大树”并不等于提倡“大树移植”。 通常称的“大树”一般指“乔木”而言。《辞海》中“乔木”辞条释为“主干明显直立,分枝繁盛的木本     

Mapping a gene conferring resistance to <Emphasis Type="Italic">Wheat yellow mosaic virus</Emphasis> in European winter wheat cultivar ‘Ibis’ (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Wheat yellow mosaic, caused by Wheat yellow mosaic virus (WYMV), is one of the most devastating soil-borne diseases of winter wheat (Triticum aestivum L.) in Japan. Yellow-striped leaves and stunted spring growth, symptomatic of WYMV infection, result in severe yield loss. A new putative WYMV resistance gene in the European wheat cultivar ‘Ibis’ was mapped in the cluster of microsatellite markers including Xcfd16, Xwmc41, Xcfd168 and Xwmc181 on the long arm of chromosome 2D at the distances of 2.0 cM, 4.0 cM, 7.1 cM and 12.4 cM, respectively. WYMV-resistant cultivars contained a common haplotype of the four markers, whereas moderately susceptible and susceptible cultivars did not. These results should be useful in marker-assisted selection for WYMV resistance in wheat.     

奇人&#183;奇行&#183;奇花

这是一组大型奇石（图1—4），石中蕴含着奇人奇行的历史故事——米芾，字元章（元1051—1107年）。宋徽宗召之为书画学博士。他平素举止清狂、违世异俗．人称“米颠”。尤嗜奇石，见辄赞叹跪拜，为历史留下了“元章拜石”的典故。     

Winter curing of <Emphasis Type="Italic">Prunus dulcis</Emphasis> cv ‘Butte,’ <Emphasis Type="Italic">P. webbii</Emphasis> and their interspecific hybrid in response to <Emphasis Type="Italic">Xylella fastidiosa</Emphasis> infections

In traditional quantitative genetics, additive effects of genes acting in a population of biparental homozygous lines are estimated on the basis of the phenotypic observations only, usually by taking a difference between mean values for extreme lines. Current molecular methods allow to estimate the additive effects by additionally taking into account the marker data. In this paper we compare these two methods of estimation of additive gene action effects analytically, by simulations and by analysis of real data sets for doubled haploid lines and recombinant inbred lines. The analytic comparison shows under which conditions an agreement of the two methods can be achieved. In most of the considered experimental data and in simulations we observe that the additive effect calculated on the basis of the marker observations is smaller than the total additive effect obtained from phenotypic observations only. This result is discussed, and a weighted regression approach is proposed as a method which can close the gap between the purely phenotypic and genotypic approaches.     

Genome constitution of <Emphasis Type="Italic">Narcissus</Emphasis> variety, ‘Tête-à-Tête’, analysed through GISH and NBS profiling

The Narcissus variety, ‘Tête-à-Tête’, has been the most popular variety since 1949, and a well known allotriploid (2n = 3x = 24 + B) of spontaneous origin. Because the identity of one of the parents of this variety was uncertain, the genome constitution of ‘Tête-à-Tête’ was investigated by using genomic in situ hybridization (GISH) and NBS profiling. Both of these techniques confirmed that two different species of Narcissus, viz., N. tazetta (2n = 2x = 20) and N. cyclamineus (2n = 2x = 14) are the parents. GISH clearly identified 10 chromosomes of N. tazetta and 14 chromosomes of N. cyclamineus, the former has contributed one and the latter has contributed two genomes. One B chromosome was identically labelled as those of N. cyclamineus indicating the affinity of the special chromosome to this species. Due to its male and female sterility ‘Tête-à-Tête’ is unsuitable as a parent for utilizing in further breeding, it might be possible to re-synthesize a ‘Tête-à-Tête’ like variety using the now known parents and the original pathway.     

Development and characterization of a <Emphasis Type="Italic">Triticum aestivum</Emphasis>-<Emphasis Type="Italic">Haynaldia villosa</Emphasis> translocation line T4VS⋅4DL conferring resistance to wheat spindle streak mosaic virus

Previous studies showed that a T. aestivum-H. villosa disomic substitution line DS4V(4D) showed a high level of resistance to wheat spindle streak mosaic virus (WSSMV). By crossing DS4V(4D) with the common wheat variety Yangmai #5, plants were obtained that were double monosomic for chromosomes 4V and 4D. Univalents are prone to misdivision at the centromere, and fusion of the derived telocentric chromosomes leads to the production of Robertsonian whole-arm translocations. We screened the progenies of such double monosomic plants by C-banding and genomic in situ hybridization and identified one compensating translocation where the short arm of 4V was translocated to the long arm of 4D of wheat, T4VS⋅4DL. RFLP analysis using the group-4 specific probe BCD110 was used to confirm the translocation. The T4VS⋅4DL translocation stock, accessioned as NAU413, is highly resistant to WSSMV and is also of good agronomic type. The WSSMV resistance gene located on 4VS was designated Wss1.     

Introduction of a Cationic Peptide, CEMA, into Cotton Caused Abnormal Phenotype and Chloroplast Degeneration

As a strategy for phytopathogen control throughtransgenic way,antimicrobial peptide genes havebeen employed over the last two decades.CEMA is a cationic antimicrobial chimericpeptide,which is produced by fusing eightamino acid residues from the antimicrobialpeptide ceropin A with a modified meltin.Threetransgenic cotton plants were generated by     

O6-0B014;B015;12;1;H;BB014

蜕?005000500010001;0006001052-54圆中的斯坦纳──莱麦斯定理推广的猜想证明魏春强安康教育学院!陕西安康7250000安康师专学报JOURNAL OF ANKANG TEACHERS COLLEGE55-56O182A002;73;H;AA002_73;魏春强000500020011000355-56斯坦纳定理推广的猜想证明黄岩陕西绥德四十铺中学!陕西绥德7180000安康师专学报JOURNAL OF ANKANG