Effects of the replacement of Glu-A1 by Glu-D1 locus on agronomic performance and bread-making quality of the hexaploid wheat cv. Courtot

The aim of this study was to evaluate the cumulative and interactive effects on wheat (Triticum aestivum L.) gluten strength and mixing properties of dough associated with the duplication of the Glu-D1 locus. A partially isohomoeoallelic line RR240, in which a segment of the wheat chromosome 1D containing the Glu-D1 locus encoding the Dx2 + Dy12 subunits and translocated to the long arm of the chromosome 1A through homoeologous recombination, was assessed. Agronomic traits and yield components were studied in the translocated line RR240 and compared with the control line cv. Courtot. Both lines were evaluated under field conditions in two experimental years. Technological effects resulting from the duplication of HMW glutenin subunits Dx2 and Dy12 were evaluated using the Alveograph test, the Mixograph test and the baking test. The RR240 line was shown to have a lower agronomic performance for 1000-kernel weight and grain yield. However the duplication of the Glu-D1 allele was associated with a significant effect on dough strength and mixing resistance, and on the Zeleny sedimentation volume. Baking parameters were not significantly modified between both lines although the score values of the CNERNA test were observed to be slightly higher in RR240 than in Courtot.     

New insights into high-molecular-weight glutenin subunits and sub-genomes of the perennial crop Thinopyrum intermedium (Triticeae)

Intermediate wheatgrass (Thinopyrum intermedium) is a perennial crop that possesses desirable agronomic traits and provides environmental services, e.g., reducing soil erosion, nitrate leaching and inputs of energy and pesticide. Thus, intermediate wheatgrass is currently being domesticated as a perennial grain crop. However, the genetic information for molecular breeding is quite limited. Here we report a molecular analysis of high-molecular-weight glutenin subunits (HMW-GS) in intermediate wheatgrass using gene cloning and protein biochemistry. Five HMW-GS genes were isolated from individual intermediate wheatgrass plants: two x-type genes TiHGS1 and TiHGS4, and three y-type genes TiHGS2, TiHGS3 and TiHGS5. Among them, TiHGS5 was novel and possessed an additional cysteine residue at the N-terminal domain or repetitive domain. Sequence alignments showed that TiHGS1 and TiHGS2 genes shared high identities (>96%) with the Glu-1Dx and Glu-1Dy genes, respectively, in common wheat and Aegilops species, TiHGS3 with HMW-GS genes from Dasypyrum or Pseudoroegneria, and TiHGS4 and TiHGS5 with HMW-GS genes from Thinopyrum elongatum. This work provides substantial new insights into the gene compositions and protein profiles of HMW-GS in intermediate wheatgrass, and also gives evidence about the genome components of intermediate wheatgrass.     

Agropyron elongatum HMW-glutenins have a potential to improve wheat end-product quality through targeted chromosome introgression

After screening of 177 disomic addition lines (DALs) of wheat (Triticum aestivum) containing a pair of chromosomes from different alien species, we found that the chromosome 1E addition line of Agropyron elongatum, that is known to be a potential genetic resource for drought and salinity tolerance, showed potential for improvement of bread-making quality of wheat. This was indicated by increased SDS sedimentation, specific sedimentation, mixograph peak time and SE-HPLC analysis of polymeric proteins. This addition line spontaneously gave rise to a substitution line for chromosome 1D in subsequent generations that showed weak dough strength. Analysis of the x-type HMW-glutenin subunit sequence of Ag. elongatum from DAL1E indicated that it closely resembled the x-type sequence of the A and B genomes of wheat, and the y-type was intermediate between x- and y-type HMW-glutenin subunit genes. From these observations, it was inferred that 1E-encoded seed storage proteins have considerable potential for improvement of wheat end-product quality if transferred to specific chromosomes such as 1A of Chinese Spring (CS) wheat, which has a negative overall effect on bread-making quality.     

Evaluation and characterization of high-molecular weight 1D glutenin subunits from Aegilops tauschii in synthetic hexaploid wheats

The high-molecular weight (HMW) glutenin subunits of bread wheat are major determinants of end-use quality. The objective of this study was to determine the 1Dx and 1Dy subunits present in 43 synthetic hexaploid wheat (SHW) lines derived by crossing durum ‘Langdon’ to 43 Aegilops tauschii accessions. Protein samples were initially electrophoresed multiple times on SDS-PAGE gels to arrange subunits into similar groups and then were electrophoresed on urea/SDS-PAGE gels. Initial results with SDS-PAGE gels indicated that there were six 1Dx and six 1Dy subunits in these SHW lines. However, results of the urea/SDS-PAGE indicated that some of the subunit groups could be further differentiated into additional subunits. A total of eleven 1Dx and eight 1Dy subunits including the newly designated subunits 1Dx2^t-1, 1Dx2^t-2, 1Dx2^t-3, 1Dx1.5^t-1, 1Dx2.1^t-1, 1Dy10^t-1, and 1Dy12^t-1 were identified, and they composed 17 1Dx and 1Dy combinations in the SHW lines. Eight of the combinations included at least one novel subunit and hence they were novel Glu-D1 alleles. Our results indicated that urea/SDS-PAGE can be very useful in identifying new HMW glutenin subunits. Quality testing of the SHW lines will determine if any of the alleles are useful in improving wheat-baking quality.     

高大山羊草 Pm13染色体片段对小麦农艺和产量性状的影响

含有高大山羊草 Pm13染色体片段的小麦种质R1B对白粉病菌表现高抗。为明确 Pm13对白粉病的抗性遗传特点及高大山羊草染色体片段对小麦农艺和产量性状的影响,利用R1B与高感小麦品种济麦22杂交获得的F_(2∶5)RIL群体进行自然诱发鉴定和分子标记分析。结果表明,发病后,RIL群体的抗、感病株系符合1∶1分离比(χ~2=3.261,χ■=3.841),说明白粉病抗性是由一对基因控制。经分子标记分析,RIL群体白粉病抗性由 Pm13控制,且符合孟德尔单基因遗传规律。RIL群体中抗白粉病组和感白粉病组间,抽穗期、开花期、株高、穗长、每穗可育小穗数、每穗不育小穗数、穗粒数、千粒重、粒长、粒宽、粒周长、长宽比等12个性状均无显著差异(P0.05),说明高大山羊草染色体片段对这些性状没有明显不利影响。鉴于 Pm13抗性遗传稳定,应加大其利用力度,培育更多含有该基因的抗白粉病品种,发挥其在生产上的应用价值。     

Agronomic and quality characteristics of triticale (X Triticosecale Wittmack) with HMW glutenin subunits 5+10

Sets of triticale (X Triticosecale Wittmack) lines derived from the cv. Presto with HMW glutenin allele Glu-D1d (subunits 5+10) translocated from bread wheat (Triticum aestivum L.) chromosome 1D to chromosome 1R were evaluated for agronomic and grain quality characteristics in 2002–2005. Two different translocation types were used: (a) single translocation 1R.1D₅₊₁₀-2 where the long arm of 1R carries the wheat segment from 1DL with the Glu-D1d replacing a secalin locus Sec-3, (b) double translocation Valdy where the long arm of 1R has the translocation 1R.1D₅₊₁₀-2 and the short arm has a segment from 1DS carrying wheat loci Gli-D1 and Glu-D3. The presence of Glu-D1d was determined by polyacrylamide gel electrophoresis (PAGE-ISTA) and DNA markers. The tested lines of triticale were compared with the check triticale cv. Presto and with wheat cultivars of different bread making quality (E-C quality classes). Single translocation 1R.1D₅₊₁₀-2 reduced grain yield by 16% and Valdy translocation by 24% as compared with cv. Presto. The Valdy translocation had substantially shortened spike length and reduced specific weight in comparison with check cv. Presto. Wet gluten content (according to the Perten method) was 12% in both translocation types, 8% in check Presto and on average 24% in wheat. Translocations increased the Zeleny sedimentation value (Valdy — 27 ml, 1R.1D₅₊₁₀-2 – 25 ml, cv. Presto — 23 ml). Triticale had a very low Hagberg falling number (FN) of 62–70 s without significant differences, while wheat had on average 301 s. The translocations did not significantly increase loaf volume; however, they improved loaf shape (height/width ratio): Valdy — 0.61, 1R.1D₅₊₁₀-2 – 0.56, cv. Presto 0.44, wheat on average 0.70. The dough was non-sticky in Valdy, slightly sticky in 1R.1D₅₊₁₀-2 and sticky in cv. Presto. Problems with a low FN for improving bread making quality of triticale are discussed. Higher bread making quality can be influenced by appropriate combination with donors of low α-amylase activity.     

Novel allelic variants encoded at the Glu-D3 locus in bread wheat

Low-molecular weight glutenin subunits (LWM-GS) are important components of wheat (Triticum aestivum L.) gluten, with important effects on end-use quality. The LMW-GS are encoded at Glu-3 loci (Glu-A3, Glu-B3 and Glu-D3, on the short arms of chromosomes 1A, 1B and 1D), each of which exhibits extensive allelic variation. Each locus encodes numerous LMW-GS, some of which have similar electrophoretic mobilities, making it difficult to distinguish among Glu-3 loci. Alleles of the Glu-D3 locus of bread wheat are considered the most problematic to assign. To date, six Glu-D3 alleles, designated a, b, c, d, e and f, have been reported. We report five previously undescribed alleles (g, h, i, j and k), and describe a method for characterizing them using a combination of SDS-PAGE and multiplexed PCR-based DNA markers. This method could be used for accurate identification of Glu-D3 alleles, permitting the estimation of the effects of these alleles on end-use quality and the selection of desirable alleles and allelic combinations in wheat breeding.     

Quality characteristics and field performance of selectable marker-free transgenic rice with antisense Wx gene and improved quality derived from the elite parents of hybrid indica rice

In rice grains, high amylose content (AC) is correlated with poor grain quality, particularly in indica hybrid rice. To obtain indica hybrid rice with improved cooking and eating qualities, we introduced the antisense Waxy (Wx) gene into 2 elite parental lines of indica hybrid rice by using co-transformation methods. Subsequently, we selected several elite homozygous transgenic lines that did not contain the selectable marker. The expression of the endogenous Wx gene of the selected transgenic lines was significantly downregulated, resulting in low AC in the mature seeds; moreover, the AC in some lines reduced to the level observed in glutinous rice. With the decrease in AC, the gel consistency of the transgenic rice became softer, and the gelatinization temperature tended to be higher than those of the wild types, especially in the case of the Longtefu-derived transformants. We also analyzed the pasting properties of the selected transgenic low-AC lines, and we noted an improvement in the pasting properties of the transgenic rice lines. The results from a field trial indicated that the grain weights of the transgenic lines with lower AC exhibit remarkable reduction compared with those of the wild types.     

PCR-based markers for identification of HMW-GS at Glu-B1x loci in common wheat

The bread wheat elasticity, which is very important for bread-making quality, is largely determined by the composition of high-molecular-weight glutenin subunits (HMW-GS). The HMW-GS encoded by Glu-B1 loci are highly polymorphic and the combinations 17+18 and 14+15 are good for bread making. Thus it is very important to identify the alleles at Glu-B1 loci for wheat quality improvement. In this study, the five common HMW-GS types encoded by Glu-B1x locus carried by 18 Chinese bread wheat cultivars (or lines) were analyzed by SDS-PAGE. Two pairs of PCR primers which could distinguish the Glu-Blx alleles of the five common HMW-GS types were designed based on the Glu-B1x gene sequences (Reddy and Appels, 1993; Genbank accession: X13927; Genbank accession:AY367771). 22 recombinant inbred lines (RILs) derived from Jing711 (contains 17 subunit on Glu-B1x) and Pm97034 (contains 14 subunit on Glu-B1x) were used to validate the accuracy of the primers, which showed that the two specific markers could be used together to distinguish alleles at Glu-B1x locus and accelerate wheat quality breeding by marker assisted selection.     

Comparative susceptibility of Ostrinia furnacalis, Ostrinia nubilalis and Diatraea saccharalis (Lepidoptera: Crambidae) to Bacillus thuringiensis Cry1 toxins

Transgenic corn hybrids that express toxins from Bacillus thuringiensis (Bt) are highly effective against the European corn borer, Ostrinia nubilalis (Hübner), and the closely related Asian corn borer, Ostrinia furnacalis (Guenée). Since the registration of Bt corn hybrids in the U.S. in 1996, there has been a great deal of information generated on O. nubilalis. However, relatively little information exists for O. furnacalis. To help determine whether the information generated for O. nubilalis can be leveraged for decisions regarding the use of transgenic Bt corn against O. furnacalis, experiments were designed to determine whether the pattern of sensitivity to various Bt Cry1 toxins is similar between the two species. Test insects included laboratory-reared O. furnacalis originating from Malaysia, a Bt-susceptible laboratory colony of O. nubilalis maintained at the University of Nebraska-Lincoln (UNL) and an out-group consisting of the sugarcane borer, Diatraea saccharalis (F.), from Louisiana which represents a different genus from the same family. O. furnacalis and O. nubilalis exhibited a similar pattern of susceptibility to all the Cry1 toxins and were highly susceptible to the range of Bt toxins tested including Cry1Aa, Cry1Ab, Cry1Ac and Cry1F. Both of the Ostrinia species were more tolerant to Cry1Ba compared with D. saccharalis, although sensitivity of O. furnacalis was intermediate and did not differ significantly from that of O. nubilalis and D. saccharalis. D. saccharalis was also susceptible to the range of toxins tested but unlike the two Ostrinia species, was more tolerant to Cry1F and more susceptible to Cry1Ba. These results indicate that both of the Ostrinia corn borer species are similar in sensitivity to the Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba and Cry1F toxins, thus suggesting shared toxin receptors and mechanisms of toxicity for the two species.     

Endophytic Lecanicillium lecanii and Beauveria bassiana reduce the survival and fecundity of Aphis gossypii following contact with conidia and secondary metabolites

Lecanicillium lecanii and Beauveria bassiana are important entomopathogens of Aphis gossypii. Their capacity to colonize crop plants is also becoming widely recognized. Their presence in crop plants indicates the possibility of a much greater potential for contact between insect and fungus than previously recognized. The present experiment aimed to study the effects of endophytic strains of these fungi on the survival, and reproduction of A. gossypii. Contact with conidia of both fungi significantly reduced the rate and period of reproduction of A. gossypii. The culture filtrates of L. lecanii and B. bassiana significantly increased mortality and feeding-choice experiments indicate that insects may be able to detect metabolites of the fungi. The culture filtrate of L. lecanii also significantly reduced the reproduction of the aphid. The ethyl acetate and methanolic fractions of the culture filtrate and of mycelia of L. lecanii also caused significant mortality and reduced fecundity of A. gossypii. The methanolic fractions of mycelia of B. bassiana caused significant mortality of A. gossypii. The present investigations indicated that A. gossypii is affected by contact with both conidia and fungal metabolites. This broad influence indicates that these fungi may have a role in regulating insect pest populations.     

Development and characterization of a Triticum aestivum-H. villosa T5VS•5DL translocation line with soft grain texture

The Hardness locus on the short arm of chromosome 5D is the main determinant of grain texture in bread wheat. The Pina and Pinb genes are tightly linked at this locus, and the soft kernel texture phenotype results when both genes are present and encode the wild-type puroindoline proteins PINA and PINB. In this study a compensating T5VS•5DL Triticum aestivum-Haynaldia villosa translocation line, NAU415, was characterized by chromosome C-banding, genomic in situ hybridization and molecular markers. Single Kernel Characterization System (SKCS) analysis and scanning electron microscopy indicated that NAU415 had soft endosperm although it lacked the wheat Pina-D1a and Pinb-D1a genes, suggesting the presence of functional Pin gene orthologs on chromosome 5VS. Using a PCR approach, Pina-related (designated Dina) and Pinb-related (Dinb) genes in H. villosa and NAU415 were identified and sequenced. The nucleotide and predicted amino acid sequences showed close similarities to the wild-type puroindolines of T. aestivum cv. Chinese Spring. The tryptophan-rich regions of both Dina and Dinb showed a sequence change from lysine-42 to arginine, a feature that may have an effect on grain texture. The potential of T5VS•5DL translocation line as a source of genes that may be used for modulation of endosperm texture and other valuable traits in wheat breeding is discussed.     

Association analysis of Puroindoline-D1 and Puroindoline b-2 loci with 13 quality traits in European winter wheat (Triticum aestivum L.)

Grain hardness, a major determinant influencing end-use quality of common wheat, is mainly controlled by Puroindoline a-D1 (Pina-D1) and Puroindoline b-D1 (Pinb-D1) genes. Recently, additional puroindoline genes, designated Puroindoline b-2 (Pinb-2), were described. This study examined frequencies of Pin-D1 alleles and Pinb-2 variants in 94 West European wheat genotypes and assessed their association with 13 quality traits considering population and family structure. The survey was completed by analyzing the Grain softness protein-1 gene. Results indicated sequence variation only for Pinb-D1 and Pinb-B2 genes. Pinb-D1b was the predominant hard allele. Pinb-B2v3-1 was the most common Pinb-2 variant, followed by a newly discovered variant Pinb-B2v3-5. Association mapping carried out in the whole sample population showed that Pinb-D1 alleles were associated with 11 quality traits, whereas Pinb-B2 variants were only associated with semolina extraction. Considering only the panel of hard wheat genotypes, variation for flour ash content, sedimentation value, gluten index and loaf volume was found to be associated with Pinb-D1 mutations suggesting that different Pinb-D1 mutations might have particular effects on quality traits. Our study indicated that Pinb-D1d was associated with inferior sedimentation value, gluten index and loaf volume, for which reason this mutation should be disregarded in breeding for quality wheat.     

Correspondence between two minor Glu-A3 genes of durum wheat and their encoded polypeptides by using a proteomic approach

The low molecular weight glutenin subunits (LMW-GS) are wheat storage proteins participating to the formation of glutenin polymers that, along with the other gluten proteins, allow the accumulation of a large quantity of protein in the endosperm tissue. The size and composition of the glutenin polymers are directly related to gluten visco-elastic properties. In particular, LMW-GS composition is the factor most influencing durum wheat quality.     

Identification of an insecticidal polyacetylene derivative from Chrysanthemum macrotum leaves

Compounds responsible for insecticidal properties of Chrysanthemum macrotum (D.R.) Ball. leaves against Spodoptera littoralis Boiduval caterpillars have been investigated. The screening of the insecticidal activity was performed by incorporating methanol, buthanol or ethyl acetate extracts, or some chromatographic fractions to the caterpillars’ artificial diet. It was noted that extracts and fractions ameliorated or disturbed nutritional indexes, being not always toxic for caterpillars. Among the tested fractions, one pure compound with a high insecticidal activity (percentage of mortality 66.7%) was purified. The nuclear magnetic resonance study allowed its identification as a polyacetylene derivative, in particular a spiroketal enol ether one.     

High level of resistance to Sclerotinia sclerotiorum in introgression lines derived from hybridization between wild crucifers and the crop Brassica species B. napus and B. juncea

Sclerotinia rot caused by the fungus Sclerotinia sclerotiorum is one of the most serious and damaging diseases of oilseed rape and there is keen worldwide interest to identify Brassica genotypes with resistance to this pathogen. Complete resistance against this pathogen has not been reported in the field, with only partial resistance being observed in some Brassica genotypes. Introgression lines were developed following hybridization of three wild crucifers (viz. Erucastrum cardaminoides, Diplotaxis tenuisiliqua and E. abyssinicum) with B. napus or B. juncea. Their resistance responses were characterized by using a stem inoculation test. Seed of 54 lines of B. napus and B. juncea obtained from Australia, India and China through an Australian Centre for International Agricultural Research (ACIAR) collaboration programme were used as susceptible check comparisons. Introgression lines derived from E. cardaminoides, D. tenuisiliqua and E. abyssinicum had much higher levels (P < 0.001) of resistance compared with the ACIAR germplasm. Median values of stem lesion length of introgression lines derived from the wild species were 1.2, 1.7 and 2.0 cm, respectively, as compared with the ACIAR germplasm where the median value for stem lesion length was 8.7 cm. This is the first report of high levels of resistance against S. sclerotiorum in introgression lines derived from E. cardaminoides, D. tenuisiliqua and E. abyssinicum. The novel sources of resistance identified in this study are a highly valuable resource that can be used in oilseed Brassica breeding programmes to enhance resistance in future B. napus and B. juncea cultivars against Sclerotinia stem rot.     

7OE+8*亚基对东北强筋小麦品种品质性状影响研究

小麦品质改良是东北春麦区强筋小麦育种的主要目标之一。Glu-B1位点7^OE+8^*亚基为超强筋小麦品种必备基因。为了明确该亚基在东北春麦区强筋小麦遗传背景下的品质遗传效应,本研究利用分子标记和选择回交相结合的手段,将7^OE+8^*亚基定向导入到强筋小麦品种龙麦26和龙麦35（Glu-B1位点均为7+9亚基）的遗传背景之中,对BC₅F₁、BC₆F₁群体和自交BC₆F₂鉴定获得的纯合品系进行7^OE+8^*亚基遗传效应评价。结果表明,在强筋小麦品种龙麦26(7+9)和龙麦35(7+9)遗传背景下转入7^OE+8^*亚基后,其干面筋、面筋指数、形成时间、稳定时间、断裂时间、拉伸面积、延伸性和最大抗延阻力等品质指标3年平均分别提高1.3%(P=0.82)和1.8%(P=0.49)、6.6%(P=0.59)和4.7%(P=0.37)、55.0%(P=0.24)和35.8%(P=0.56)、44.5%(P=0.43)和32.8%(P=0.73)、41.4%(P=0.31)和30.0%(P=0.66)、28.0%(P=0.05)和23.4%(P=0.37)、6.5%(P=0.47)和5.8%(P=0.42)、19.5%(P=0.31)和18.0%(P=0.38);Zeleny沉降值2年平均分别提高6.8%和11.4%。以上结果表明,在2个强筋小麦品种遗传背景下,Glu-B1位点转入7^OE+8^*亚基较7+9亚基对各项品质指标改良均存在正向效应,但提高幅度存在差异,对形成时间、稳定时间、断裂时间、最大抗延阻力、拉伸面积等衡量面筋质量的指标提高幅度更大,表明该亚基对面筋质量改良效应显著。综上所述,7^OE+8^*亚基可作为东北春麦区强筋小麦遗传背景下品质性状进一步改良的优选基因,为超强筋小麦育种的重要基因资源。     

Management of the root-knot nematode Meloidogyne incognita on tomato with combinations of different biocontrol organisms

The nematicidal effect of Pseudomonas fluorescens, Paecilomyces lilacinus, Pichia guilliermondii and Calothrix parietina singly or in combination was tested against root-knot nematode, Meloidogyne incognita. Treatments with P. fluorescens and P. lilacinus caused mortality of M. incognita as 45% and 30% of juveniles after 48 h of exposures, respectively compared to water control in vitro. Under greenhouse conditions, all treatments reduced the disease severity and enhanced plant growth compared to untreated control. Application of P. fluorescens, P. lilacinus and P. guilliermondii Moh 10 was more effective compared to C. parietina. There was a negative interaction between C. parietina and either P. lilacinus or P. guilliermondii. Fresh and dry weight of shoots and roots of plants were significantly reduced as a result of infection with M. incognita, however application of biocontrol agents singly or in mix recovered this reduction. Moreover, they enhanced the growth parameters compared with the control. Our results proved that application of different biocontrol agents (P. fluorescens, P. lilacinus and P. guilliermondii) not only has a lethal effect on nematode, but also enhances the plant growth, supplying many nutritional elements and induction the systemic resistance in plants. Presence of C. parietina as a soil inhabitant cyanobacterium could antagonize biocontrol agents leading to the reduction of their practical efficiency in soil.     

Characterization of Solanum chomatophilum resistance to 2 aphid potato pests, Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer)

The aphids Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer) (Hemiptera: Aphididae) are responsible for yield reduction in potato (Solanum tuberosum) production by direct phloem feeding and by spreading viruses. Breeding resistant traits from Solanum chomatophilum into the potato germplasm provides alternative means to control aphid infestations. Integrated pest management strategy, using plant resistance, benefits from the characterization of the resistance and of its impact on aphid biology. Our objective was to characterize the resistance of S. chomatophilum by assessing the effects of accessions, plant parts on aphid performance, and by assessing the impact of the resistance factors on different aphid developmental stages and on alate morph production. Detailed aphid performance was obtained by measuring fecundity, survival, percentage of nymphs that reached adult moult, and population growth using whole plant and clip cage experimental designs. Accession and plant physiological age, but not aphid developmental stage, influenced all life-history parameters, except for alate morph production which was not induced on the resistant accessions. Plant part influence was independent of plant species and accession. Both experimental designs resulted in congruent resistance levels at the accession level for each of the two aphid species, supporting the use of any of them in S. chomatophilum resistance screening. PI243340 was resistant to both aphid species, while PI365324 and PI310990 were also resistant to M. euphorbiae and M. persicae, respectively.     

Mycoparasitic Trichoderma viride as a biocontrol agent against Fusarium oxysporum f. sp. adzuki and Pythium arrhenomanes and as a growth promoter of soybean

Trichoderma viride was proved as an effective biocontrol agent against two fungal pathogens, Fusarium oxysporum f. sp. adzuki and Pythium arrhenomanes, infecting soybean. During an in vitro biocontrol test, Trichoderma showed mycoparasitism and destructive control against the tested fungal pathogens. Both the pathogens significantly influence the germination and P. arrhenomanes had a severe effect (only 5% germination). The root system of the soybean plant was poorly developed due to the infection and it exerted a negative influence on the nodulation and further growth phases of the plant. During pot assay along with biocontrol activity, Trichoderma showed growth promoting action on the soybean plant. Trichoderma enhanced growth of shoot and root systems and fruit yield after 12 weeks of growth. Pythium and Fusarium infected plants treated with Trichoderma had ∼194% and 141% more height than pathogens alone. The fruit yield treated with Trichoderma was ∼66 per plant whereas the yield was only 41 for a control plant. The plants infected with Pythium and Fusarium and treated with Trichoderma had fruit yields of 43 and 53 respectively and those were 5 and 1.6 times higher than plants infected with pathogens.