scholarly journals Screening of sweetpotato germplasm collections for sweetpotato weevil (Cylas spp.) resistance in Tanzania

2020 ◽  
pp. 1707-1714
Author(s):  
Filson Kagimbo ◽  
Hussein Shimelis ◽  
Julia Sibiya
Keyword(s):  
Durable Resistance ◽  
Resistance Breeding ◽  
Root Weight ◽  
Root Number ◽  
Storage Roots ◽  
Damage Score ◽  
Sweetpotato Weevil ◽  
Lattice Design ◽  
Germplasm Collections ◽  
Western Tanzania

Weevil damage caused by sweetpotato weevil (Cylas spp.) is a major constraint to sweetpotato production in Tanzania due to a lack of improved varieties with durable resistance. The objective of this study was to screen sweetpotato germplasm collections for weevil resistance and to select the best parents to be used in resistance breeding. Field studies involving 96 sweetpotato genotypes were conducted at two weevil hotspot sites in Western Tanzania using a 12 x 8 lattice design with three replications at each site. Data collected included yield and yield related traits, weevil reaction and weevil damage score. The tested genotypes differed significantly (P < 0.01) for sweetpotato storage root number, root weight, root infestation and root damage score. Weevil infestation on storage roots significantly (P ≤0.05) correlated with total root number (r = 0.38) and weevil damage score (r = 0.79). Marketable root weight and total root weight were significantly correlated with infested root weight each with r = 0.45. The study identified nine sweetpotato genotypes expressing resistance and 10 genotypes with moderate resistance to weevil. Five genotypes including Magunhwa, Chuchu ya Nesi, Rugomoka, Tumauma and New Kawogo were selected with weevil resistance and desirable yield and yield-related traits. These genotypes can be used in future weevil resistance breeding programs of sweetpotato in Western Tanzania or related agro-ecologies.

scholarly journals Search for Resistant Genotypes to Cuscuta campestris Infection in Two Legume Species, Vicia sativa and Vicia ervilia

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 738
Author(s):  
Eva María Córdoba ◽  
Mónica Fernández-Aparicio ◽  
Clara Isabel González-Verdejo ◽  
Carmela López-Grau ◽  
María del Valle Muñoz-Muñoz ◽  
...  
Keyword(s):  
Agricultural Production ◽  
Host Plants ◽  
Resistance Breeding ◽  
Parasitic Plants ◽  
Vicia Sativa ◽  
Common Vetch ◽  
Germplasm Collections ◽  
Bitter Vetch ◽  
Cuscuta Campestris ◽  
Resistant Genotypes

The dodders (Cuscuta spp.) are parasitic plants that feed on the stems of their host plants. Cuscuta campestris is one of the most damaging parasitic plants for the worldwide agricultural production of broad-leaved crops. Its control is limited or non-existent, therefore resistance breeding is the best alternative both economically and environmentally. Common vetch (Vicia sativa) and bitter vetch (Vicia ervilia) are highly susceptible to C. campestris, but no resistant genotypes have been identified. Thus, the aim of this study was to identify in V. sativa and V.ervilia germplasm collections genotypes resistant to C. campestris infection for use in combating this parasitic plant. Three greenhouse screening were conducted to: (1) identify resistant responses in a collection of 154 accessions of bitter vetch and a collection of 135 accessions of common vetch genotypes against infection of C. campestris; (2) confirm the resistant response identified in common vetch accessions; and (3) characterize the effect of C. campestris infection on biomass of V. sativa resistant and susceptible accessions. Most common vetch and bitter vetch genotypes tested were susceptible to C. campestris. However, the V. sativa genotype Vs.1 exhibited high resistance. The resistant phenotype was characterized by a delay in the development of C. campestris posthaustorial growth and a darkening resembling a hypersensitive-like response at the penetration site. The resistant mechanism was effective in limiting the growth of C. campestris as the ratio of parasite/host shoot dry biomass was more significantly reduced than the rest of the accessions. To the best or our knowledge, this is the first identification of Cuscuta resistance in V. sativa genotypes.

scholarly journals Influence of cutting type and size on rooting of Lavandula dentata L

2012 ◽  
Vol 14 (1) ◽  
pp. 8-11 ◽  
Author(s):  
C.M. Bona ◽  
I.R. Biasetto ◽  
M. Masetto ◽  
C. Deschamps ◽  
L.A. Biasi
Keyword(s):  
Essential Oil ◽  
Vegetative Propagation ◽  
Plant Material ◽  
The Other ◽  
Root Weight ◽  
Root Number ◽  
Polystyrene Foam ◽  
High Quality ◽  
Cutting Propagation ◽  
Superior Clones

Even though the Lavandula species may be propagated by seeds, it should not be the preferred propagation method because it causes a great lack of uniformity. On the other hand, asexually propagated lavender crops would provide more homogeneous crops, and clones from high quality plant material would increase the odds for obtaining a higher quality essential oil. However, problems such as poor rooting and restrict market availability for superior clones have been a problem in vegetative propagation of the Lavandula species. The objective of this work was to define which type and size of cutting is more adequate for cutting propagation of L. dentata, a very productive Lavandula species. Cuttings with 5, 8, 10 or 13 cm and from the apical or basal parts of stems cut from L. dentata stock plants were placed in Plantmax HT® filled polystyrene foam trays and kept under intermittent mist system for two months. Averages of root number, length of the longest root, fresh and dry root weight, and percentage of rooting were evaluated. Apical cuttings combined 97.9% rooting with an average of 13.2 roots per cutting and basal cuttings 93.7% rooting with 2.98 roots per cutting. Apical cuttings with at least 10 cm in length were considered the most adequate for cutting propagation of L. dentata.

scholarly journals Surface Chemical Differences Between Sweetpotato Lines with Varying Levels of Resistance to the Sweetpotato Weevil

1990 ◽  
Vol 115 (4) ◽  
pp. 696-699 ◽  
Author(s):  
Ki-Cheol Son ◽  
Ray F. Severson ◽  
Richard F. Arrendale ◽  
Stanley J. Kays
Keyword(s):  
Ipomoea Batatas ◽  
Methylene Chloride ◽  
Chemical Characterization ◽  
Fused Silica ◽  
Storage Roots ◽  
Sweetpotato Weevil ◽  
Or Groups ◽  
Fused Silica Capillary ◽  
Silica Capillary Column

Methodology was developed for the extraction of surface components of sweetpotato [Ipomoea batatas (L.) Lam.] storage roots. Surface components of storage roots were quantitatively extracted with methylene chloride using 8-minute ultrasonication. After removal of the solvent, the extract was treated with 3 Tri Sil-Z:1 trimethylsilylimidazol (v/v) to convert components with hydroxyl moieties to silyl ethers and then separated on a SE-54 fused silica capillary column. Distinctly different gas chromatography profiles were found between lines displaying moderate levels of resistance (`Resisto', `Regal', `Jewel') to the sweetpotato weevil [Cylas formicarius elgantulus (summers)] and weevil-susceptible lines (`Centennial', SC 1149-19, W-115), indicating a possible role of surface components in insect response. Chromatographic fractionation techniques were developed for separation of major components or groups of components. The results will allow subsequent bioassaying for the presence of an ovipositional stimulant(s) and other weevil behavior-modulating compounds and their chemical characterization.

Quantification of antibiosis levels in nine different rice genotypes against Nilaparvata lugens (Homoptera: Delphacidae)

2018 ◽  
Vol 38 (04) ◽  
pp. 330-339
Author(s):  
P. S. Sarao ◽  
J. S. Bentur
Keyword(s):  
Brown Planthopper ◽  
Growth Index ◽  
Resistance Breeding ◽  
Nilaparvata Lugens ◽  
Female Population ◽  
Damage Score ◽  
Survival Percentage ◽  
Honeydew Excretion ◽  
Rice Genotypes ◽  
Better Than

AbstractStudies on different parameters of antibiosis to simultaneously compare diverse genotypes with different resistance levels are lacking. Such studies are necessary to identify the genetic variability among resistant genotypes, which, ultimately, can lead to the identification of resistance genes with diverse mechanisms. The current study was undertaken to quantify antibiosis levels in nine rice genotypes against the brown planthopper (BPH), Nilaparvata lugens (Stål), under glasshouse conditions using nine parameters. Among these genotypes, RP2068-18-3-5 and Ptb33 displayed significantly better performance as compared to other genotypes in most of the parameters studied and did not differ from each other. Rathu Heenati was the best in unfertilised eggs laid and similar to the above two genotypes regarding percent of nymphal survival. All the test genotypes performed significantly better than the susceptible check TN1, though INRC3021 did not differentiate from the former in some tests. The overall damage score was positively and significantly correlated with the amount of honeydew excretion, percent nymphal survival and emergence, the proportion of brachypterous females, female population, and growth index, and were negatively and significantly correlated with percent unfertilised eggs laid and nymphal development period. Regression analysis revealed a significant linear relationship between damage score and nymphal emergence, nymphal survival percentage, and proportion of brachypterous females. RP2068-18-3-5 is the new source of BPH resistance identified through this study, which breeders can further use in resistance breeding.

scholarly journals Race structure of cowpea witchweed (Striga gesnerioides) in West Africa and its implications for Striga resistance breeding of cowpea

Weed Science ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Erik W. Ohlson ◽  
Michael P. Timko
Keyword(s):  
West Africa ◽  
Resistance Genes ◽  
Broad Spectrum ◽  
Genetic Relatedness ◽  
Durable Resistance ◽  
Resistance Breeding ◽  
Differential Resistance ◽  
African Countries ◽  
Sources Of Resistance ◽  
Striga Gesnerioides

AbstractCowpea witchweed [Striga gesnerioides (Willd.) Vatke] is a primary constraint of cowpea [Vigna unguiculata (L.) Walp.] production in West Africa. Previously, seven S. gesnerioides races were classified based upon host specificity and genotypic profiling. Because race number and distribution are dynamic systems influenced by gene flow, genetic drift, and natural selection, a thorough investigation of S. gesnerioides diversity and the effectiveness of known sources of resistance in cowpea is needed to develop varieties with durable and broad-spectrum Striga resistance. In this study, we screened seven cowpea lines against 58 unique S. gesnerioides populations collected from across nine West African countries. Individuals from 10 S. gesnerioides populations were genotyped with simple sequence repeat (SSR) markers. We identified six races of S. gesnerioides based on their parasitism of the seven cowpea lines with known differential resistance genotypes. No cowpea line was resistant to all 58 Striga populations and none of the Striga populations were able to overcome the resistance of all seven lines. A novel race, SG6, of the parasite collected from Kudu, Nigeria, was found to overcome more cowpea resistance genes than any previously reported race. SSR analysis indicates that Striga populations are highly differentiated and genetic relatedness generally corresponds with geographic proximity rather than their host compatibility. Due to the dearth of broad-spectrum resistance found among Striga-resistant cowpea lines, there exists a need to stack multiple Striga resistance genes in order to confer broad-spectrum and durable resistance.

scholarly journals Organic mulches reduce crop attack by sweetpotato weevil (Cylas formicarius)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mudassir Rehman ◽  
Jian Liu ◽  
Anne C. Johnson ◽  
Taiwo Esther Dada ◽  
Geoff M. Gurr
Keyword(s):  
Water Conservation ◽  
Organic Materials ◽  
Management Practice ◽  
Integrated Management ◽  
Weed Suppression ◽  
Crop Damage ◽  
Storage Roots ◽  
Plant Materials ◽  
Sweetpotato Weevil ◽  
Cylas Formicarius

Abstract Mulching with organic materials is a management practice with long history for weed suppression, soil water conservation and erosion control. Its potential impact on crop pests is less well explored. Here we report its utility for reducing crop damage by the serious pest, sweetpotato weevil (Cylas formicarius). Laboratory bioassays measured the response of adult female weevils to sweetpotato storage roots beneath mulches of fresh or dried plant materials. Weevils were significant repelled by fresh basil, catnip, basil lime and dry eucalyptus, cypress, lucerne and sugarcane. A subsequent field study found that mulches of dry cypress, eucalyptus and lucerne reduced movement of weevils from a release point to reach sweetpotato plants and lowered level of damage to storage roots. Results demonstrate that mulching with organic materials merits further testing as part of the integrated management of sweetpotato weevil, particularly to protect developing storage roots during dry periods when soil cracking can facilitate access by pests.

scholarly journals Impact of some chemical treatments and length of storage on the storability of sugar beet

2016 ◽  
Vol 5 (1) ◽  
pp. 96-106
Author(s):  
Hussien Al Zubi ◽  
Entessar Al Jbawi ◽  
Sameer Al Jeddawi ◽  
Mohammad Khair Tahla ◽  
Raafat Ismaiel ◽  
...  
Keyword(s):  
Calcium Chloride ◽  
Agricultural Research ◽  
Sugar Content ◽  
Storage Period ◽  
Root Weight ◽  
Storage Roots ◽  
Chemical Application ◽  
Chemical Treatments ◽  
Slaked Lime ◽  
Factor C

An experiment was conducted at the Agricultural Research Center of Al Ghab, General Commission for Scientific Agricultural Research (GCSAR), Syria, to evaluate the effect of some chemical application on the sugar losses reduction, and some quality traits in 2014/2015 season. Three slaked lime concentrations of 5, 10 and 15 percent, and three concentrations of calcium chloride of 2, 4, and 6%, and a mix of 5% slaked lime with 2% calcium chloride, beside the check (no treatment) (factor C). The second factor (D) was the storage durations of 6 days, and tow varieties (Factor V) were arranged as factorial experiment in RCBD with four replications. The varieties one of them was monogerm (Vico), while the other was multigerm (Reda), they were drilled in mid November, and storage roots were harvested late August. Weight percent loss and quality of beet samples such as sugar content, total soluble solids (TSS %), and purity% were determined throughout storage period. The results of analysis of variance ANOVA showed that effect of varieties was significant for TSS (brix %), sucrose%, root weight loss (P<0.05). All the studied traits were affected significantly (P<0.05) by storage duration. Chemical treatments had significant effect on all the studied traits (P<0.05), and the best treatment was with calcium chloride 6%. The percentage of variance confirmed that the most effective factor for the all studied traits was the storage period, followed by the varieties, and finally in a very low percent was the chemical treatments, because of that it is very urgent to send the harvested roots immediately to the factories to be processed within 24 hours, or treated with calcium chloride of 6% to preserve the sugar content as possible till manufacturing. Also the study concluded that the mutigerm variety Reda deteriorated less that the monogerm variety Vico, so Reda is recommended to be stored if necessary.International Journal of Environment Vol. 5 (1) 2016,  pp: 96-106

scholarly journals The quality of carrot (Daucus carota L.) cultivated in the field depending on iodine and selenium fertilization

2016 ◽  
Vol 28 (2) ◽  
pp. 151-164 ◽  
Author(s):  
Sylwester Smoleń ◽  
Łukasz Skoczylas ◽  
Iwona Ledwożyw-Smoleń ◽  
Roksana Rakoczy ◽  
Marta Liszka-Skoczylas ◽  
...  
Keyword(s):  
Daucus Carota ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Dry Weight ◽  
Root Weight ◽  
Storage Roots ◽  
Selenium Compounds ◽  
Daucus Carota L ◽  
Selenium Fertilization

AbstractThe aim of the study was to evaluate the influence of various chemical forms of iodine (I−and IO3−) and selenium (SeO32−and SeO42−) on the nutritional and health-promoting quality of carrot (Daucus carotaL.) storage roots. The experiment (conducted in 2012-2014) comprised the soil fertilization of carrot ‘Kazan’ F1in the following combinations: 1. Control, 2. KI, 3. KIO3, 4. Na2SeO4, 5. Na2SeO3, 6. KI + Na2SeO4, 7. KIO3+ Na2SeO4, 8. KI + Na2SeO3, 9. KIO3+ Na2SeO3. Iodine and selenium were applied twice: before sowing and as top dressing in a total dose of 5 kg I ha−1and 1 kg Se ha−1. No significant influence of iodine and selenium fertilization was noted with respect to average root weight and leaf yield. Each year, the application of KI + Na2SeO4negatively affected the content of glucose and total sugars in carrot. An increased sucrose level was noted in the roots of plants treated with KIO3+ Na2SeO4, with a total sugar concentration comparable to the control. Irrespective of the year, carrots fertilized with KI were characterized by the highest accumulation of nitrates (III) – NO2−in roots. The simultaneous introduction of iodine and selenium compounds (KI + Na2SeO4, KIO3+ Na2SeO4, KI + Na2SeO3and KIO3+ Na2SeO3) into the soil reduced the content of nitrates (III) in carrot as compared to combinations with the individual application of these compounds. The influence of the tested factors on other analysed parameters (the content of dry weight, nitrates (V), chlorides, oxalates, citrates, free amino acids, carotenoids, phenolic compounds, phenylpropanoids, flavonols and anthocyanins as well as free radical scavenging activity (DPPH) was rather year-dependent.

scholarly journals Specificity of TAS-ELISA for Beet Necrotic Yellow Vein Virus and Its Application for Determining Rhizomania Resistance in Field-Grown Sugar Beets

Plant Disease ◽  
1999 ◽  
Vol 83 (9) ◽  
pp. 864-870 ◽  
Author(s):  
G. C. Wisler ◽  
R. T. Lewellen ◽  
J. L. Sears ◽  
H.-Y. Liu ◽  
J. E. Duffus
Keyword(s):  
Sugar Beet ◽  
Sugar Industry ◽  
Resistance Breeding ◽  
The United States ◽  
Crop Rotations ◽  
Yellow Vein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Root Weight ◽  
Sugar Beets ◽  
Rhizomania Resistance

Levels of beet necrotic yellow vein virus (BNYVV), as measured by triple-antibody sandwich-enzyme-linked immunosorbent assay (TAS-ELISA), were compared with biological evaluations in representative commercial and experimental sugar beet cultivars developed for production in the United States and ranging in their reactions to rhizomania from uniformly susceptible to highly resistant. TAS-ELISA was specific for BNYVV and did not react with related soilborne sugar beet viruses. Differences in absorbance (A405nm) values measured in eight cultivars closely correlated with the dosage and frequency of the Rz allele, which conditions resistance to BNYVV. A diploid (Rzrz) hybrid had a significantly lower absorbance value (less virus) than a similar triploid (Rzrzrz) hybrid. Cultivars that segregated (Rzrz:rzrz) had higher absorbance values than uniformly resistant (Rzrz) hybrids, as was expected. For all cultivars, absorbance values decreased as the season progressed. Absorbance value was significantly positively correlated with rhizomania disease index score and negatively correlated with individual root weight, plot root weight, and sugar yield. This information should be useful in resistance-breeding and -evaluation programs and in the sugar industry when considering cultivar choice, inoculum production, and future crop rotations.

scholarly journals Adventitious rooting of auxin-treated Lavandula dentata cuttings

2010 ◽  
Vol 40 (5) ◽  
pp. 1210-1213 ◽  
Author(s):  
Claudine Maria de Bona ◽  
Luiz Antonio Biasi ◽  
Bernardo Lipski ◽  
Magda Aparecida Maia Masetto ◽  
Cícero Deschamps
Keyword(s):  
Essential Oil ◽  
Oil Content ◽  
Adventitious Rooting ◽  
Root Weight ◽  
Root Number ◽  
Quadratic Regression ◽  
Polystyrene Foam ◽  
Rooted Cuttings ◽  
Significant Difference ◽  
The Mean

Lavandula species may be propagated by seeds. However, plants will present expressive variation both in size and essential oil content. Indole-3-butyric acid (IBA) is a growth regulator which efficiently stimulates rooting and the objective of this research was to observe the influence of different IBA concentrations on rooting of L. dentata cuttings. Herbaceous cuttings with approximately 10cm in length and around 1/3 of leaf retention had their bases submerged into 0 (control), 500, 1.000, 2.000 or 3.000mg dm-3 of IBA diluted in de-ionized water for 30 seconds and placed in polystyrene foam trays filled with commercial substrate and kept under intermittent mist system. Averages of root number, length of the longest root, fresh and dry root weight, and percentage of rooted cuttings were evaluated after 60 days. There was no significant difference between treatments for the length of root, fresh and dry root weight. The percentage of rooted cuttings increased with IBA concentrations. A quadratic regression was obtained to root number. The 2.000mg dm-3 dose increased the percentage of rooted cuttings and the mean root number per cutting. L. dentata cuttings are easy to root.

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