Growth and yield of self-compatible and hybrid common buckwheat lines pollinated with and without flies

Common buckwheat is a self-incompatible, insect-pollinated allogamous plant. This study examined growth and yield of the common buckwheat self-compatible and hybrid lines pollinated with and without flies. Self-compatible ‘IH3’, hybrid ‘IP2/IH3’, and standard self-incompatible ‘Kitawasesoba’ were used in field and pot experiments. Self-compatibility of ‘IH3’ was shown to be of high purity. Approximately 10% segregation of pin plants from ‘IP2/IH3’ was observed. The harvest index of ‘Kitawasesoba’ pollinated without flies was considerably lower than that pollinated with flies in both field and pot experiments. The harvest index values of ‘IH3’ and ‘IP2/IH3’ were hardly affected by the presence or absence of flies. The morphological traits of ‘IH3’ were significantly lower than those of the other two genotypes. Large differences in these traits between ‘IP2/IH3’ and ‘Kitawasesoba’ were not observed in either the field or pot experiments. The seed yield of ‘Kitawasesoba’ pollinated without flies tended to be lower than that pollinated with flies. The seed yield of ‘IP2/IH3’ tended to be higher than that of ‘IH3’. The hybrid line ‘IP2/IH3’ showed a high fertilization rate, which was nearly as high as that of ‘IH3’. Rate of fertilization and percentage of ripe seeds were higher in ‘IH3’ and ‘IP2/IH3’, wherein they were hardly affected by the presence or absence of flies, than in ‘Kitawasesoba’. The ‘IP2/IH3’ hybrid line will be useful for understanding the stable high-yielding ability of self-compatibility common buckwheat.     

Cytological and biochemical changes induced by chitosan in the pathosystem Alternaria alternata-tomato

The cytological and biochemical response of the fungus Alternaria alternata to chitosan application in tomato fruits was evaluated. The research was developed in the following stages: microscopically to observe the degree of damage that chitosan causes over the conidia and hyphae of the fungus at the structural level and during the infection process in tomato tissue. Biochemically we tried to identify the elicitation of the phytoalexin rhisitin and other compounds involved in resistance. At the microscopic level, mycelium and conidia of chitosan-treated of A. alternata showed cell wall disintegration, plasma membrane retraction, cellular distortion, release of the apical portion of the conidia and lysis of fungal cells. Hyphae and conidia were susceptible to chitosan application. Infection always took place in chitosan treated and inoculated tomatoes and it was difficult to observe ultrastructural alterations due to chitosan application. The phytoalexin rhisitin was not isolated from any of the treatments but other compounds such as alkenes, fatty acids and vitamin E whose antimicrobial effects have been reported were detected. The elicitation of precursor compounds in the pathosystem A. alternata-tomato was more associated with the infection process than with the chitosan application. Further studies are necessary to confirm these findings.     

螺旋粉虱对不同甜椒品种的产卵选择性及与植物中化学物质的相互关系研究

［目的］ 明确螺旋粉虱对不同甜椒品种的产卵偏好性及其与甜椒体内化学物质含量的关系。［方法］ 采用非自由选择法测定了螺旋粉虱对不同甜椒品种的产卵偏好性,并测定不同甜椒品种体内单宁酸、总黄酮、可溶性糖、可溶性蛋白等化学物质含量,分析其与螺旋粉虱产卵选择的相关性。［结果］ 螺旋粉虱对‘古风7号’的选择性最强,产卵量显著高于‘特大型牟一号’、‘吉星’、‘京椒’、‘特大甜椒八号’等8个品种（α=0.05水平）,而与‘国禧205’、‘郑椒甜宝’、‘古风5号’等7个品种差异不显著。不同甜椒品种间的单宁酸含量、总黄酮含量、可溶性糖含量、可溶性蛋白含量存在显著差异。相关分析表明,螺旋粉虱对甜椒品种的选择性与单宁酸、总黄酮不相关,与可溶性蛋白呈负相关,与可溶性糖含量呈正相关。［结论］ 螺旋粉虱对不同甜椒品种的偏好性存在显著差异,这种差异与甜椒体内一些化学物质含量不同有关。     

番茄绿果与橙果间果实颜色及主要色素含量的遗传研究

对番茄组合绿樱(绿果)×金珠1号(橙果)的6个世代遗传群体(P1、P2、F1、BC1、BC2和F2)进行果色性状、番茄红素含量、叶绿素含量和胡萝卜素含量等的遗传规律分析。结果表明:正反交F1的果色性状无明显差异,而色素含量存在显著差异;说明番茄果色性状受核基因控制,而色素含量遗传除受核基因控制外还可能存在胞质效应。采用多世代联合分析法的分析结果表明,番茄绿果与橙果间的果色性状符合2对加性主基因+加性-显性多基因(MX2-A-AD)遗传模型,其BC1、BC2和F2主基因遗传率分别为73.42%、78.25%和61.41%,多基因遗传率分别为22.87%、15.35%和34.94%,即果色性状遗传的主基因遗传力较强;叶绿素含量符合1对负向显性主基因+加性-显性多基因(MX1-AEND-AD)遗传模型,其BC1、BC2和F2主基因遗传率分别为0、1.73%和0.65%,多基因遗传率分别为45.47%、0和37.82%,即主基因遗传力在BC2群体中最高,多基因遗传力在BC1群体中最高;番茄红素含量与胡萝卜素含量均符合2对加性-显性-上位性主基因+加性-显性多基因(MX2-ADI-AD)遗传模型,其BC1、BC2和F2主基因遗传率分别为75.74%、1.79%、84.26%和61.53%、87.21%、81.05%,多基因遗传率分别为20.32%、74.12%、12.68%和0.68%、0、0,表明番茄红素含量和胡萝卜素含量的主基因遗传力较强。     

普通荞麦染色体的原位PCR技术研究

[目的]探索一种适合荞麦的简单易行的染色体原位PCR技术。[方法]采用16S套式引物、4．5S套式引物与psbA引物，以栽培甜荞为材料，进行染色体原位PCR、原位套式PCR与多次原位PCR试验。[结果]高温干燥可以起到与包埋类似的作用；染色体的原位套式PCR效果比原位PCR明显，多次原位PCR次数为5-6效果较佳。16S引物和4．5S引物均显示了4对信号，但位置不同；而psbA引物是单拷贝的，仅显示出1对信号。根据这些信号的位置差异可以区分普通荞麦的5对染色体。[结论]所使用的荞麦染色体原位PCR技术简单易行。     

A CAPS marker TAO1902 diagnostic for the I-2 gene conferring resistance to Fusarium oxysporum f. sp. lycopersici race 2 in tomato

Fusarium oxysporum f. sp. lycopersici inhabits most tomato-growing regions worldwide, causing tomato production yield losses. A molecular marker linked to resistance would be useful for tomato improvement programmes. Thus, a cleaved amplified polymorphic sequence (CAPS) marker TAO1₉₀₂ was developed to identify tomato genotypes possessing the I-2 gene, which confers resistance to F. o. lycopersici race 2. The Rsa I or Fok I restriction fragments corresponded to the presence or absence of the I-2 allele in a segregating 100 F₂ progeny, tomato cultivars, 16 resistant and 20 susceptible to Fusarium wilt, respectively, lines and F₁ hybrids, representing various tomato gene pools. TAO1₉₀₂ may be helpful for selection of F. o. lycopersici -resistant tomato germplasm.     

Pistillate-parental differences and the ability to produce interspecific hybrids between Lycopersicon esculentum and 'peruvianum-complex' species (L. peruvianum and L. chilense)

To overcome the cross-breeding barriers between the cultivated tomato Lycopersicon esculentum and the ‘peruvianum-complex’, hybrid production ability (HPA) and pistillate-parental differences were investigated. As a criterion of HPA, the number of germinated ovules per fruit (GPF) was used. GPF was expressed as GPF = OPF × GPO, where OPF is the number of ovules per fruit, and GPO is the proportion of germinated ovules to total ovules obtained. The interspecific crossing between nine varieties and three ‘peruvianum-complex’ accessions revealed that the cultivars ‘Sekaiichi’,‘Ponde Rooza’ and ‘Early Pink’ showed quite high and stable GPF over the years, but the cv.‘Best of All’ produced no hybrids. Variance analysis for GPF, OPF and GPO, and their correlation with seven sexual organ morphological traits and three fruit morphological traits were performed. These results indicated that choosing both the pistillate parents with wider reproductive organs for high OPF and appropriate environmental conditions for high GPO might be significant for enhancing GPF in interspecific crossing.     

In vitro selection of tomato transformants at the immature embryo stage

Summary A method is described for selecting resistant transformed tomato genotypes in vitro at the stage of immature embryos. The utilization of HLH nutrient medium with the selective agent kanamycin is proposed. Normal development of seedlings from immature embryos, which do not form callus, is a good and true indicator for isolation of resistant genotypes. The immature embryos do not germinate and develop on MS selective medium.     

Estimating the pleiotropic effect of the jointless-2 gene on the processing and agronomic traits of tomato by using near-isogenic lines

Two near-isogenic lines of the processing tomato cv. ‘IPA-5’, pheno-typically distinct from each other only in terms of the presence or absence of a jointless fruit pedicel, were used to estimate pleiotropic effects of the recessive gene j-2 on 15 processing and agronomic parameters. Total yield, total yield of mature fruit, total yield of green fruit, total number of fruit, total number of mature fruit, total number of green fruit, mean weight of mature fruit, mean weight of green fruit, mean weight of mature plus green fruit, soluble solids, fruit colour, pH, titratable acidity, sugar: acid ratio, and fruit firmness were compared in jointed (J-2/J-2) and jointless pedicel (J-2/J-2) lines. Statistically significant differences were detected between both isolines for the following parameters: total number of fruit, total yield, total yield of green fruit, and total number of green fruit. In all cases, smaller values were observed in the isoline with the genetic constitution J-2/J-2. These data reinforce the view that they j-2 gene may cause, in some specific tomato backgrounds, significant yield constraints. Furthermore, it was demonstrated that this gene cannot exert any important pleiotropic influence on any of the processing characteristics evaluated.     

Performance of Solanum habrochaites LA1777 introgression line hybrids for marketable tomato fruit yield in Asia

Wild relatives of the cultivated tomato (Solanum lycopersicum L.) are major sources of new genetic diversity for tomato improvement. Introgression lines (IL) are near-isogenic lines homozygous for one or several mapped wild DNA fragments in a common recurrent parent. A set of ILs developed by Cornell University from Solanum habrochaites accession LA1777 and recurrent parent E6203 has been made publicly available through the Tomato Genetics Resource Center of the University of California-Davis. Our objective was to identify LA1777 introgressions with potential to increase the marketable fruit yield of tomato grown in the tropics. A subset of ILs were each crossed to CLN2498E (resistant to bacterial wilt and some begomoviruses) to create IL hybrids (ILH). ILH, IL recurrent parent E6203, CLN2498E, and CLN2498E × E6203 (Hchk) were evaluated in replicated trials in Thailand, India, and Taiwan during two dry seasons. Highly significant effects for marketable fruit yield were detected in Thailand and Taiwan. ILH heterozygous for S. habrochaites segments at the bottom of chromosome 1 yielded about 20% than the Hchk at Thailand and Taiwan. Our results agree with previous results from Cornell University researchers who found a segment of S. habrochaites DNA located between TG158 and TG27 associated with increased total fruit yield in previous trials conducted in upper state New York. Yield improvement due to this S. habrochaites introgression can occur over a wide range of environments.