Role of Microbial Biopesticides as an Alternative to Insecticides in Integrated Pest Management of Cotton Pests

Cotton (Gossypium hirsutum L.) is the most produced natural fibre worldwide, and it contributes significantly to the economy of almost 80 cotton-producing countries. Given the high pest infestation, huge amounts of insecticides have been used in cotton production. However, this has resulted in the development of resistance from primary cotton pests and contamination of the environment. Furthermore, the reduction of beneficial insects and outbreaks of secondary pests have been observed. Many arthropod pests are associated with cotton, most of which belong to the orders Lepidoptera, Thysanoptera, and Hemiptera. Biocontrol agents play a critical role in preventing pests in most cotton-growing areas globally. Biological control of cotton pests forms part of integrated pest management as most of these pests have developed resistance against synthetic pesticides. This chapter focuses on the effects of some of the biopesticides, on cotton insect pests. It examines the control of cotton pests using microbial-based products Bacillus thuringiensis, Beauveria bassiana, Helicoverpa armigera nucleopolyhedrovirus and Metarhizium rileyi. Furthermore, the chapter summarizes the application of microbial biopesticides as well as the advantages and disadvantages of using these biocontrol agents in agriculture

Breeding wheat for drought tolerance: Progress and technologies

AbstractRecurrent drought associated with climate change is among the principal constraints to global productivity of wheat (Triticum aestivum (L.) and T. turgidum (L.)). Numerous efforts to mitigate drought through breeding resilient varieties are underway across the world. Progress is, however, hampered because drought tolerance is a complex trait that is controlled by many genes and its full expression is affected by the environment. Furthermore, wheat has a structurally intricate and large genome. Consequently, breeding for drought tolerance requires the integration of various knowledge systems and methodologies from multiple disciplines in plant sciences. This review summarizes the progress made in dry land wheat improvement, advances in knowledge, complementary methodologies, and perspectives towards breeding for drought tolerance in the crop to create a coherent overview. Phenotypic, biochemical and genomics-assisted selection methodologies are discussed as leading research components used to exploit genetic variation. Advances in phenomic and genomic technologies are highlighted as options to circumvent existing bottlenecks in phenotypic and genomic selection, and gene transfer. The prospects of further integration of these technologies with other omics technologies are also provided

A comparison of the effect of genetic improvement, seed source and seedling seed orchard variables on progeny growth in Eucalyptus nitens in South Africa

Eucalyptus nitens is an important forestry species grown for pulp and paper production in the temperate, summer-rainfall regions of South Africa. A tree improvement programme has been ongoing at the Institute for Commercial Forestry Research for two decades, but genetic improvement in the species has been slow due to delayed and infrequent flowering and seed production. Three trials were established, firstly, to quantify the gains that have been made in the first generation of improvement in the breeding programme and, secondly, to establish whether a number of seed source and orchard variables influence the performance of the progeny. These variables were the amount of flowering trees in the seed orchard, year of seed collection, seed orchard origin and composition of seed orchard bulks. Diameter at breast height and tree heights were measured in the trials at between 87 and 97 months after establishment, and timber volumes and survival were calculated. Improved seed orchard bulks performed significantly better (p<0.01) than unimproved controls in the field trials. Genetic gains ranging from 23.2 to 164.8 m3ha−1 were observed over the unimproved commercial seed. There were significant differences (p<0.01) in progeny growth between the levels of seed orchard flowering, with higher levels of flowering (≥40 %) producing substantially greater progeny growth than lower flowering levels (≤20 %). The seed orchard had no effect on progeny growth in this trial series. This suggests that seed collected from any of the four seed orchards tested will produce trees with significant improvement in growth.http://link.springer.com/journal/11295hj201

Genetic characterisation of a Eucalyptus nitens base breeding population in South Africa

The measurement and statistical analysis of data from eight Eucalyptus nitens trials, established in the summer rainfall forestry region of South Africa during the 1980s and 1990s, have enabled the characterisation of the Institute for Commercial Forestry Research’s breeding population. Provenance testing showed that the more northerly New South Wales (Australia) Eucalyptus nitens provenances of Barren Mountain and Barrington Tops are distinctly better suited to the summer rainfall areas of South Africa than the southern New South Wales provenances and the Victorian provenance, Penny Saddle. Generally, the species was not badly affected by Coniothyrium canker. High type B genetic correlations for all site pairs, except one comparison, ranged from 0.75 to 0.99 for diameter at breast height (dbh), indicating very little or no genotype environment interaction for dbh for the genotypes tested in this study. Narrow-sense heritability coefficients ranged from 0.01 to 0.34, indicating that the species generally exhibited sufficient breeding opportunity for improvement of diameter growth. High genetic correlations of greater than 0.90 between diameter measurements at 52 to 62 months after establishment and diameter measurements at 94 or 113 months were found, indicating that selections can be reliably made at five or six years. Predicted genetic gains were highest in the trials at Goedehoop and Arthur’s Seat, with increases in dbh of 3.07 cm (17.1%) and 3.17 cm (20.7%), respectively, at full rotation.http://www.tandfonline.com/loi/tsfs20hj201

Fall armyworm infestation and development : screening tropical maize genotypes for resistance in Zambia

DATA AVAILABILITY STATEMENT : All data are provided in the manuscript.SUPPLEMENTARY MATERIAL : TABLE S1: Artificial diet used for laboratory rearing of FAW. TABLE S2: Mean performance and AUPPCs of 63 tropical maize genotypes when evaluated under artificial FAW infestation. TABLE S3: Nature and magnitude of FAW damage revealed by 63 tropical maize genotypes evaluated under artificial FAW infestation. Supplementary FIGURE S1: Diets used for rearing FAW on petri dishes. S1A- Natural diet of maize leaves and stalks. S1BArtificial diet containing wheat, soy and other ingredients. Supplementary FIGURE S2: Rearing cage for adult FAW moths.Knowledge of fall armyworm (FAW) (Spodoptera frugiperda J.E. Smith) rearing, infestation and development and precision screening protocols are preconditions for the successful introgression of resistance genes into farmer-preferred varieties. We aimed to determine FAWdevelopmental stages, screen tropical maize and select resistant lines under controlled conditions in Zambia. Field-collected FAWsamples constituting 30 egg masses and 60 larvae were reared using maize leaf- and stalk-based and soy- and wheat flour-based diets at 27 1 C, 60 5% relative humidity and 12 h day length. The resulting neonates were separated into sets A and B. The life cycles of set A and field-collected larvae were monitored to document the FAW developmental features. Set B neonates were used to infest the seedlings of 63 diverse tropical maize genotypes. Egg, larva, pupa and adult stages had mean durations of 2, 24, 20 and 12 days, respectively. Test maize genotypes revealed significant differences (p < 0.05) based on FAWreaction types, with lines TL13159, TL02562, TL142151, VL050120 and CML548-B exhibiting resistance reactions, while CML545-B, CZL1310c, CZL16095, EBL169550, ZM4236 and Pool 16 displayed moderate resistance. These genotypes are candidate sources of FAW resistance for further breeding. This study will facilitate controlled FAW rearing for host screening in the integration of FAW resistance into market-preferred maize lines.The Alliance for a Green Revolution (AGRA) through the African Centre for Crop Improvement (ACCI) and the International Foundation for Science (IFS).https://www.mdpi.com/journal/insectsam2023Zoology and Entomolog

An investigation of assumptions made in estimating genetic parameters and predicting genetic gain in a Eucalyptus nitens breeding programme in South Africa

It is important to have an understanding of the population genetics and validity of the pertinent underlying assumptions of a species in order to design an effective breeding strategy. In a South African breeding population of Eucalyptus nitens, various scenarios investigating a range of assumptions were developed and used to predict genetic gain in the F2. These were compared with realised gains achieved in a series of genetic gain trials. In the two scenarios using firstly, actual flowering for family (provenance) and, secondly, estimated flowering after 30 % roguing of poor families, a coefficient of relationship of 0.33 resulted in predictions closest to realised gain, on average. The statistical information suggested that outcrossing in the seed orchards was[80 %. Indications were that the effects were additive, and that very little or no heterosis had occurred, due to the still significant provenance effects and the lack of provenance rank changes in the F2. The custom of assuming a degree of inbreeding (and using a coefficient of relationship of 0.33) and of including provenance effects in the models, on average resulted in genetic gain predictions which were very similar to the realised genetic gains in this population of E. nitens.Masonite Ltd., Mondi Ltd, NCT Forestry Co-Operative Ltd., PG Bison, TWK Ltd. and York Timbers Ltd.http://link.springer.com/journal/110562016-01-31hb201

A high-resolution view of the jets in 3C 465

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. https://doi.org/10.1093/mnras/staa147.We present new high-resolution and high-sensitivity studies of the jets in the WAT source 3C 465, using deep transverse-resolved radio observations from e-MERLIN, and with complementary observations from the VLA. We derive a lower limit $\beta_{\rm j}$ = ($\nu_{\rm j}$/$c$) $\gtrsim$ 0.5 for the jet speed, and an upper limit $\theta_{\rm j}$ $\lesssim$ 61$^{\circ}$ for the jet angle to the line of sight. The jet spectral index ($\alpha$, defined in the sense $S \propto \nu^{\alpha}$) is fairly constant ( = $-$0.7), and spectral flattening within 4.4 kpc of the core coincides with bright knots and is consistent with the site of X-ray particle acceleration at the base of the radio jet found in previous studies. There is little difference between the spectra of the two hotspot components, plausibly indicating that electron populations of the same properties are injected there. The NW and SE plumes are approximately homologous structures, with variations in mass injection and propagation in external pressure and density gradients in the two regions plausibly accounting for the slightly steeper spectrum in the NW plume, = $-$1.43 compared with the SE plume, = $-$1.38. Our synchrotron lifetime model supports plausible reacceleration of particles within the plume materials. Overall, our results show that the first-order Fermi process at mildly relativistic and non-relativistic shocks is the most likely acceleration mechanism at play in 3C 465 and distinguish differences between the acceleration at $\beta_{\rm j}$ $>$ 0.5 and $\beta_{\rm j}$ $Peer reviewe

Combining ability for grain yield and resistance to maize streak virus in maize

Combining ability effects for grain yield, yield-related traits and resistance to maize streak virus (MSV) were determined using 10 parents, 45 single crosses and five standard hybrid checks. Genotypes were evaluated at three locations (Ngaramtoni, Inyala, and Igomelo) over two seasons (2012/13 and 2013/14) using a 6 x 10 simple lattice design with two replications. Data were collected for days-to-50% silking (DSL), days-to-50% anthesis (DA), reaction to MSV disease, plant height (PHT), ear height (EHT), number of ears per plant (EPT), husk cover of cobs (HSC) and grain yield (YLD). General combining ability (GCA) and specific combining ability (SCA) effects were significant (P < 0.05) for all traits except DA and DSL. Parental line TL2012-42 was the best general combiner for YLD, while the parents TL2012-41, TL2012-1 and TL2012-42 were the best combiners for maize streak virus resistance, with negative GCA effects of -10.9%, -10.8% and -10.7%, respectively. The highest SCA effect for grain yield (4.80) was detected in the hybrid TL2012-7/TL2012-38. Crosses such as TL2012-38/TL2012-55 and TL2012-25/TL2012-26 had negative SCA effects for their MSV reaction. The above parental lines and hybrids can be recommended for direct production, or breeding to enhance grain yield and MSV resistance in maize varieties for Tanzania

Variance components and heritability of traits related to Striga asiatica resistance and compatibility to Fusarium oxysporum F.Sp. Strigae in maize

Genetic gain in breeding maize for yield and yield components and Striga resistance is dependent on the magni-tude of genetic variation and heritability. The objective of this study was to determine variance components and heritability of yield and yield-related traits and Striga asiatica (L.) Kuntze resistance in maize involving a bio-control agent Fusarium oxysporum f.sp. strigae (FOS). Eighteen selected and genetically diverse maize populations were evaluated across nine testing environments in three sites under three levels of FOS treatment during the 2016/2107 growing season using an alpha lattice design with two replications. Variance components, heritability estimates and correlations among S. asiatica traits, grain yield and yield components of maize were calculated to provide a selec-tion guide. Significantdifferences (P0.5) were recorded for ear aspect (0.58), cob length (0.60), grain yield t ha-1 (0.61), grain yield plant-1 (0.65), cob diameter (0.83), 100 kernel weight (0.91); Striga counts (0.71) and Striga damage rating (0.75). Grain yield t ha -1 and its components were negatively corre-lated with Striga parameters under FOS treatments. Yield-related traits such as cob length, cob diameter, and 100 kernel weight were important in indirect selection for FOS compatible and Striga resistant maize genotypes. FOS could serve as an effective bio-control agent against S. asiatica in maize production using compatible genotype

The Reddest Quasars

In a survey of quasar candidates selected by matching the FIRST and 2MASS catalogs, we have found two extraordinarily red quasars. FIRST J013435.7-093102 is a 1 Jy source at z=2.216 and has B-K > 10, while FIRST J073820.1+275045 is a 2.5 mJy source at z=1.985 with B-K = 8.4. FIRST J073820.1+275045 has strong absorption lines of MgII and CIV in the rest frame of the quasar and is highly polarized in the rest frame ultraviolet, strongly favoring the interpretation that its red spectral energy distribution is caused by dust reddening local to the quasar. FIRST J073820.1+275045 is thus one of the few low radio-luminosity, highly dust-reddened quasars known. The available observational evidence for FIRST J013435.7-093102 leads us to conclude that it too is reddened by dust. We show that FIRST J013435.7-093102 is gravitationally lensed, increasing the number of known lensed, extremely dust-reddened quasars to at least three, including MG0414-0534 and PKS1830-211. We discuss the implications of whether these objects are reddened by dust in the host or lensing galaxies. If reddened by their local environment, then we estimate that between 10 and 20% of the radio-loud quasar population is reddened by dust in the host galaxy. The discovery of FIRST J073820.1+275045 and objects now emerging from X-ray surveys suggests the existence of an analogous radio-quiet red quasar population. Such objects will be entirely missed by standard radio or optical quasar surveys. If dust in the lensing galaxies is primarily responsible for the extreme redness of the lensed quasars, then an untold number of gravitationally lensed quasars are being overlooked.Comment: AASTEX 24 pp., 7 figs; accepted by ApJ. See also the preprint astro-ph/0107435 by Winn et al., who independently discovered that J013435.7-093102 is gravitationally lense