Survey of faba bean (Vicia faba L.) for viruses in Morocco

A total of 52 faba-bean (Vicia faba L.) fields, located in the main growing areas in Morocco were surveyed for viruses. From 240 samples with symptoms suggestive of virus infection, the following viruses were detected using electron microscopy, serology, and biological indexing: Alfalfa mosaic virus (AMV), bean yellow mosaic virus (BYMV), broad bean mottle virus (BBMV), broad bean stain virus (BBSV), broad bean true mosaic virus (BBTMV), pea earlybrowning virus (PEBV), pea enation mosaic virus (PEMV), pea seed-borne mosaic virus (PSbMV), and a complex of luteoviruses including bean leafroll virus (BLRV). This is the first report of the occurrence of BBTMV, PEMV, PSbMV, and the luteoviruses (including BLRV) of faba bean in Morcco. The luteoviruses and BBMV were found to be the most prevalent. They were detected in 56 and 50%, respectively, of the surveyed fields; while AMV, BBSV, and PEBV were found in single fields only. The remaining viruses were less prevalent, and were detected in a range of 4 to 15% of the fields surveyed. The incidences per field of the prevalent viruses varied and ranged from 1 to 33% for BBMV and up to 20% in the case of luteoviruses. BBMV was found confined to the central and northern parts of the country, BBTMV and PEMV mainly occurred in the central area, while the luteoviruses and BYMV were spread over the faba-bean growing regions of the country.     

Effects of virus infection of faba bean on subsequent infection by Uromyces viciae-fabae

Prior infection of faba bean with bean yellow mosaic virus (BYMV) and bean leaf roll virus decreased pustule density on leaves subsequently infected by Uromyces viciae-fabae. Changes were most marked on young leaves showing conspicuous symptoms of systemic virus infection and in plants virus-infected for at least 2-4 weeks. Pustule density progressively decreased when inoculations were made with uredospore generations successively produced on and inoculated to BYMV-infected leaves.
Uredospore germination and germ tube length were similar on virus-free and BYMV-infected leaves and on agar seeded with spores produced for one or several generations on BYMV-infected or virus-free plants. Formation of appressoria was slightly reduced on BYMV-infected leaves but changes in the post-penetration development of the rust probably accounted for much of the decreased pustule production encountered.     

Relationship between physiological response of French beans of different age to Meloidogyne incognita and subsequent yield loss

A study was made of the effect of a single generation of the root-knot nematode Meloidogyne incognita on the growth of potted French bean plants ( Phaseolus vulgaris ) inoculated at different stages of plant maturity. In separate experiments. 3-, 11- and 13-day-old plants were inoculated before primary leaf expansion (BPLE). at the appearance of trifoliate leaves (TRIF) and at the flower bud (BDS) stages respectively, with 0, 2000, 4000 or 8000 second-stage juvenile nematodes and maintained in a growth chamber under controlled conditions. The photosynthetic rate of the plants inoculated at the TRIF and BDS stages decreased significantly with increasing inoculum level 7 days after inoculation. Although the respiration rate did not significantly change throughout the experimental period, the ratio of photosynthetic to respiration rate decreased significantly with increasing nematode inoculum level and duration of infection. Chlorophyll content, plant dry weight and the numbers of buds, flowers, pods and seeds were significantly lower in infected plants than in the controls; this effect increased with increasing levels of nematode inoculum for all three plant stages. The leaf area was significantly smaller only when nematode infection occurred at the BPLE stage. The plants which were youngest at the time of nematode infection produced the lowest yield; this appeared to result from the effect of nematodes on photosynthesis and related physiological processes.     

Virus-induced changes in the response of faba bean to infection by Botrytis

Prior infection of faba bean with the viruses bean yellow mosaic and bean leaf roll increased host susceptibility to subsequent infection by Botrytis fabae and B. cinerea. Cell necrosis beneath inoculum droplets, rate and extent of lesion spread and sporulation of B. fabae were all increased on detached leaves from virus-infected compared with healthy plants. Changes were most marked in young leaves showing conspicuous symptoms of systemic virus infection and in plants virus-infected for at least 2-4 weeks. Localized lesions produced by B. cinerea or a low concentration of B. fabae conidia (10³ spores/ ml) showed increased cell necrosis but were not transformed into aggressive, spreading lesions on virus-infected leaves.     

The natural occurrence of bean yellow mosaic, cucumber mosaic and tobacco mosaic viruses in lisianthus in Israel

Mosaic on leaves, necrosis, stunting and flower symptoms were observed in lisianthus ( Eustoma russellianum ) raised from seed. Three viruses, bean yellow mosaic (BYMV), cucumber mosaic (CMV) and tobacco mosaic (TMV), were isolated. Virus identification was based on electron microscopy, host range, aphid transmission and serology.     

种植模式与施磷深度对蚕豆群体冠层结构及其产量的影响

在小区试验与大田生产试验条件下,采用三个种植密度(12 000株·667m-2,13 000株·667m-2,14000株·667m-2)、两个留苗方式(一穴单株,一穴双株)及三个施磷深度(10 cm,15 cm,20 cm)处理,通过裂区试验研究了高产蚕豆群体冠层结构指标及其对产量的影响,结果表明,13 000株·667m-2、15 cm施磷深度、双株三角留苗种植模式下,盛花期蚕豆群体叶面积指数、叶绿素SPAD值,主根长均维持在较高水平,冠层结构较优,产量最高,达到275.2 kg·667m-2;生产试验显示,"一穴双株"能有效提高蚕豆结荚率,提高产量,较常规栽培增产14%以上。提出以"深松增密,减穴加距,中层施磷"为主要内容的蚕豆高产栽培技术。     

基于连续14年国家绿豆品种区域试验的中国绿豆品种产量和性状变化

利用GGE双标图、变异系数法、相关性分析、多元回归和聚类分析等方法,分析了2003—2016年共14 a国家绿豆品种区域试验中来自内蒙古自治区、黑龙江省、吉林省、辽宁省、山西省等12个绿豆主产省（市、自治区）的29个育种单位提供的130个参试品种的生育天数、株高、主茎节数、主茎分枝数、荚长、单株荚数、荚粒数、千粒重以及产量在春播组和夏播组的变异,并比较了性状间的相关性以及不同育种单位选育的绿豆品种的性状差异。结果表明：2003—2016年春播组和夏播组绿豆产量分别增加14.0%和25.4%,年均增幅分别为1.0%和1.8%;主茎分支数分别减少12.0%和15.9%;其他性状变化不明显。春播组绿豆主要农艺性状的变异系数为5.14%~17.01%,均值为11.33%;遗传多样性指数为1.91~2.08,平均为1.99。夏播组绿豆主要农艺性状的变异系数为5.96%~19.99%,均值为12.52%;遗传多样性指数为1.98~2.17,平均为2.07。相关性和偏相关性分析表明,春播组中产量与荚长、单株荚数和荚粒数显著正相关,与其他性状的相关性不明显;夏播组中产量与单株荚数和荚粒数显著正相关,与株高、主茎分支数和荚长显著负相关。多元回归分析表明,春播组绿豆生育天数、株高、主茎分支数、荚长和单株荚数共同决定产量60.9%的变异;夏播组绿豆株高、主茎分枝数、单株荚数、荚粒数和千粒重共同决定产量87.7%的变异。依托品种选育区域的聚类分析表明,65个春播组品种被分为4类,在北京市、河北省、山西省、河南省、山东省、吉林省和陕西省综合表现较好;65个夏播组品种被分为6类,在河南省、河北省和山东省综合表现较好。2003—2016年,国家每轮区试的绿豆品种产量稳步提升,表明我国绿豆育种水平有了一定提升;但品种遗传基础狭窄,育种方法多样化程度较低,缺少突破性品种。     

Albugo candida staghead formation in Brassica juncea in relation to plant age, inoculation sites, and incubation conditions

Maximum staghead formation was obtained in 26-day-old (growth stage [GS] 3.1) Brassica juncea plants by inoculating differentiating flower buds with a zoospore suspension of Albugo candida race 2 V; exposing apical meristem tissues by opening the flower buds with forceps proved more conducive to staghead formation. Inoculation of 35- and 45-day-old plants (GSs 4.1 and 5.0, respectively) produced fewer hypertrophies, mainly in isolated flowers. Inoculation of 7- and 13-day-old plants (GSs 1.0 and 2.1, respectively) did not produce any hypertrophied flowers, but did result in the production of hypertrophied branches at the first node on the main stem. In general, hypertrophies were initiated more readily under greenhouse conditions than in the growth chamber. Other Brassica hosts inoculated with A. candida race 2 V or 7 V at GS 31 showed similar rankings for staghead formation and leaf infection. The technique should prove useful in screening breeding lines for disease resistance, particularly staghead formation, the most damaging phase as far as yield loss is concerned.     

Resistance to Monopartite Begomoviruses Associated with the Bean Leaf Crumple Disease in Phaseolus vulgaris Controlled by a Single Dominant Gene

ABSTRACT Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Málaga virus are monopartite begomoviruses (genus Begomovirus, family Geminiviridae) that infect common bean (Phaseolus vulgaris), causing bean leaf crumple disease (BLCD). This disease was found to be widespread in southern Spain and causes stunted growth, flower abortion, and leaf and pod deformation in common bean plants. Commercial yield losses of up to 100% occur. In the present study, we have identified and characterized a resistance trait to BLCD-associated viruses in the common bean breeding line GG12. This resistance resulted in a complete absence of BLCD symptoms under field conditions or after experimental inoculation. Our analysis showed that virus replication was not inhibited. However, a severe restriction to systemic virus accumulation occurred in resistant plants, suggesting that cell-to-cell or long-distance movement were impaired. In addition, recovery from virus infection was observed in resistant plants. The reaction of P. vulgaris lines GG12 (resistant) and GG14 (susceptible), and of F(1), F(2), and backcross populations derived from them, to TYLCV inoculation suggested that a single dominant gene conferred the BLCD resistance described here.     

Genotypic influences on the incidence of infection by Ascochyta fabae in winter-hardy faba beans (Vicia faba)

Variation in resistance to Ascochyta fabae among winter-hardy genotypes of faba bean was demonstrated in artificially inoculated field trials. The incidence of seed infection after harvest was strongly correlated with both foliar and pod infection. Joint regression of the incidence of pod infection on flowering date and length of straw accounted for 33–56% of the variance but this largely reflected the behaviour of the entries with a determinate habit which were very susceptible and sensitive to infection by A. fabae. Two indeterminate lines which were similar to each other in flowering date and straw length contrasted greatly in the incidence of foliar and pod infection.     

4个PGPR菌株拌种对干旱条件下蚕豆生长及产量的影响

于播种前,以5×108 CFU/mL浓度的PGPR菌株B9601 Y2, FZB42, B2 和 B9拌种蚕豆,在全生育期土壤重度干旱条件下,与清水拌种相比,它们均能提早出苗,促进幼苗生长,增加植株地上和地下重量与荚果数,B9601 Y2,FZB42,B2和B9菌株分别增加蚕豆株荚数0.65个、0.50个、0.05个和0.33个,有效荚数0.68个、0.53个、0.08个、0.28个,果荚重4.56 g、3.36 g、2.13 g、0.36 g,株粒数1.18粒、1.55粒、0.80粒、0.15粒,百粒重5.28 g,5.75 g,3.72 g,2.50 g,豆粒产量14.49%,12.04%,6.28%,2.21%。     

Phenotypic influences on the incidence of infection by Ascochyta fabae in spring varieties of faba beans (Vicia faba)

Spring beans with a range of different growth habits were assessed for resistance to Ascochyta fabae. Variation in the incidence of both foliar and pod infection was recorded but there was no association between the two. The larger-podded broad bean types had a higher incidence of pod infection relative to foliar infection than the smaller-podded field beans. The effect of straw length on the incidence of A. fabae was investigated using exogenously applied gibberellin to sensitive and insensitive cultivars. This confirmed the association between long straw and low incidence of pod disease.     

云南美人蕉病毒病病原鉴定

In this study,the causal agents were identified from Canna indica viral diseased plants in Yunnan Province.The diseased C.indica plants mainly exhibited the symptoms like veinal chlorosis and yellowing,streak mosaic or interveinal chlorosis,while older leaves always showed veinal necrosis as well as chlorosis.Viral pathogens were detected by RT-PCR/PCR in 24 diseased C.indica samples collected from Kunming and Yuxi City in Yunnan Province.The results indicated that the main C.indica-infecting viruses were canna yellow mottle virus (CaYMV),bean yellow mosaic virus (BYMV),sugarcane mosaic virus (SCMV).CaYMV showed the highest detection rate of 87.5 %,whereas,the BYMV had the lowest rate of 16.7% in the 24 samples.Co-infections of CaYMV+SCMV,CaYMV+BYMV and CaYMV+SCMV+BYMV were also detected in the diseased samples.However,cucumber mosaic virus (CMV),tobamovirus,luteovirus,orthotospovirus,begomovirus and umbravirus were not detected in these samples.This is the first report of CaYMV and SCMV infecting C.indica in Yunnan province.     

云南美人蕉病毒病病原鉴定

In this study,the causal agents were identified from Canna indica viral diseased plants in Yunnan Province.The diseased C.indica plants mainly exhibited the symptoms like veinal chlorosis and yellowing,streak mosaic or interveinal chlorosis,while older leaves always showed veinal necrosis as well as chlorosis.Viral pathogens were detected by RT-PCR/PCR in 24 diseased C.indica samples collected from Kunming and Yuxi City in Yunnan Province.The results indicated that the main C.indica-infecting viruses were canna yellow mottle virus (CaYMV),bean yellow mosaic virus (BYMV),sugarcane mosaic virus (SCMV).CaYMV showed the highest detection rate of 87.5 %,whereas,the BYMV had the lowest rate of 16.7% in the 24 samples.Co-infections of CaYMV+SCMV,CaYMV+BYMV and CaYMV+SCMV+BYMV were also detected in the diseased samples.However,cucumber mosaic virus (CMV),tobamovirus,luteovirus,orthotospovirus,begomovirus and umbravirus were not detected in these samples.This is the first report of CaYMV and SCMV infecting C.indica in Yunnan province.     

A competition index for Orobanche crenata Forsk effects on broad bean (Vicia faba L.)

The influence of broomrape (Orobanche crenata Forsk) infection levels on commercial broad bean (Vicia faba L.) crops was investigated and an equation relating yield losses to O. crenata density was derived. O. crenata growth was weakly and negatively related to the final height or shoot number of the broad bean plant. O. crenata decreased seed yield mainly by reducing the number of pods. The number of seeds per pod was also decreased by O. crenata infection when competition occurred at late-crop growth stages when most of the pods had already developed. Bean unit seed weight was only weakly affected by infection. Correlation coefficients between O. crenata number and broad-bean seed yield per plant were significant at P=0·05 and greater than 0·70 in most locations. On average, about four O. crenata per broad-bean plant decreased seed yield by half. An estimation of the percentage of losses in any field can be calculated from the equation: %loss = 100 × 0·124 × OcN. where OcN is the average final number of emerged O. crenata per plant.     

Pollination of chasmogamous flowers and the effects of light and emergence time on chasmogamy and cleistogamy in Monochoria vaginalis

Monochoria vaginalis is one of the most serious weeds of rice fields in Asia. The species has both chasmogamous (CH) and cleistogamous (CL) flowers on individual plants. The objective of this study is to clarify the reproductive characteristics that affect the selfing rate of M. vaginalis. An emasculation experiment revealed that the CH flowers emasculated just after flower opening produced seeds. The seed production in the flowers emasculated just after flower opening was less than that of the flowers emasculated and hand‐pollinated with pollen from another plant. These results indicate that, although self‐pollination before anthesis occurs, cross‐pollination also can produce seeds. An experimental manipulation of light and the emergence time of the plants revealed that more than half of the flowers produced were CL flowers and the CH/CL ratio decreased with reduced light availability. The plants that emerged later produced as many CH flowers as those that emerged earlier. There was no significant difference between the CH and CL flowers in the seed number per fruit and the seed mass. These results suggest that M. vaginalis has reproductive characteristics that make the selfing rate high; however, outcrossing also can occur. Under favorable light intensity conditions, such as on the edges of paddy fields or in fallow fields, M. vaginalis will produce more CH flowers and will have a higher outcrossing rate than in shaded conditions.     

Flower infection of Brassica oleracea with Xanthomonas campestris pv. campestris results in high levels of seed infection

During seed production, Brassica seed may become infected with Xanthomonas campestris pv. campestris after systemic colonization of plants upon leaf infection, or alternatively, after flower infection. Polytunnel experiments were conducted in 2007 and 2008 to study the relative importance of these colonization routes resulting in seed infection. Cauliflower plants (Brassica oleracea) were spray-inoculated at the 8-leaf stage, after formation of cauliflowers or during flowering, at which stage leaves or blossoms were inoculated. Inoculation at all stages resulted in a relatively high percentage of systemic infection; the average estimated infection incidences for stem base and peduncle infections were 16 % and 19 %, respectively. When seed samples were examined by dilution plating for deep-seated infection following hot water treatment, Xcc was detected in 61 % of the 23 seed samples harvested from plants with inoculated flowers. However, symptom development in seedlings raised from the seeds could not be confirmed in a grow-out test under favourable conditions for Xcc infection at a high RH (>95 %) and a relative high temperature (28 °C). Xcc was not detected in 59 seed samples harvested from leaf-inoculated plants with the exception of one sample from plants inoculated at peduncle formation. In a third polytunnel experiment carried out in 2009, the population dynamics of Xcc on inoculated flowers was investigated. Following spray-inoculation of flowers, 52 % of the flowers were infected with Xcc. During development of siliques, infection incidence decreased slowly and at 56 dpi, 20 % of the superficially disinfected siliques were infected with Xcc. It was estimated that 0.18 % of the seeds was infected and that 1–10 % of the infected siliques contained infected seeds. The implications of these results for control of Xcc in a seed production crop are discussed.     

House sparrows (Passer domesticus (Linn.)) causing severe damage to peach buds in residential areas at Ludhiana,Punjab

Abstract

House sparrow (Passer domesticus (Linn.)) damage to peach flower buds/flowers was observed during 1978–1985 in the Aggar Nagar (Ludhiana) residential locality. At the flower bud stage, sparrows destroy the buds completely by eating or damaging them so that no flowers are produced, but leaf buds and young leaves remain untouched. The average yield of the Flordasun peach cultivar is 75 kg per tree (Anonymous, 1985) but in the present case only 0 to approximately 2 kg fruit were produced per tree.     

Temporal Dynamics of the Biocontrol Agent Pseudomonas fluorescens Strain A506 in Flowers in Inoculated Pear Trees

ABSTRACT The colonization of individual flowers in mature pear orchards by Pseudomonas fluorescens strain A506 applied at different times during bloom was measured to determine the receptivity of flowers to colonization and the extent of intra-tree movement over time. Strain A506 populations in flowers open at inoculation were initially about 10(4) cells per flower and increased to approximately 10(6) cells per flower in flowers that were inoculated within about 5 days of opening. However, eventual populations decreased with further increases in flower age at inoculation to as few as about 10(3) cells per flower when inoculated flowers were more than 10 days old. Populations of strain A506 on flowers that opened after inoculation was initially very low at the time of petal expansion (<100 cells per flower) but increased rapidly with time after flower opening. The maximum population of strain A506 that developed on such flowers decreased with increasing time between inoculation and petal expansion; 10(4) to 10(5) cells of strain A506 eventually colonized flowers that opened within 7 days of inoculation, whereas fewer than 100 cells colonized flowers that opened 24 days or more after inoculation. Large total bacterial populations on A506-treated trees were associated with significant reductions in populations of Erwinia amylovora and reduced incidence of fire blight and severity of fruit russet.     

First report of flower chafer beetle, Oxycetonia versicolor, on pigeonpea and mungbean from Punjab, India

The occurrence of flower chafer beetle, Oxycetonia versicolor (Fabricius) (Scarabaeidae: Coleoptera) damaging the flowers of important grain legumes such as pigeonpea (Cajanus cajan (L.) Millsp.) and mungbean (Vigna radiata (L.) Wilczek) is reported for the first time from Punjab, India. Heavy infestation of these flower beetles at flowering may cause considerable damage to these crops. A mild to moderate level of infestation of 15?C17 beetles per ten plants was recorded at the time of peak flowering period on both the grain legumes. Adult beetles devour the flowers and buds, thereby greatly reducing the number of pods that are set. Information on important taxonomic characters of the beetle is highlighted in this report. Careful monitoring and timely reporting on this chafer beetle is necessary to avoid any future outbreak.