A Method For Improving Decentralized Task Allocation For Multiagent Systems in Low-Communication Environments.

Communication is an important aspect of task allocation, but it has a cost and low communication restricts the information exchange needed for task allocation. As a result, a lot of decentralized task allocation algorithms perform worse as communication worsens. The contribution of this thesis is a method to improve the performance of a task allocation algorithm in low-communication environments and reduce the cost of communication by restricting communication. This method, applied to the Consensus Based Auction Algorithm (CBAA), determines when an agent should communicate and estimates the information that will be received from other agents. This method is compared to other decentralized task allocation algorithms at different levels of communication in a ship protection scenario. Results show that this method when applied to CBAA performs comparably to CBAA while reducing communication

Seed yam tuber production from vine cuttings

Seed yam tuber production accounts for 30 per cent to 50 per cent of total cost of production. Efforts to obtain seed yam tubers from vine cuttings are still rudimentary, and research information available is scanty and sparse. Studies to compare the effectiveness of vine cuttings for seed yam tuber production were conducted in 2010 at International Institute of Tropical Agriculture, Ibadan, Nigeria, with a clone of Dioscorea rotundata (white yam) TDr 95/18544. Vine cuttings (VCs), with one node, one leaf, and 10 – 15 cm long were cut from the middle portion of the stems of 90-days old mother plants. Healthy VCs were planted singly in a rooting medium, and the rooted VCs were transplanted to the field at 40 days after planting, and harvested 110 days after transplanting when the leaves had senesced. Screenhouse-derived plants (SDP) originated from tissue culture have a higher survival percentage than cuttings from field-derived plants (FDP). Higher shoot formation was also observed in SDP whilst no shoot from FDP. Mean yield of tubercles from SDP was 8.5 times higher (P = 0.05) than yield from FDP. The mean percentage change in the yield of tubercles obtained from the cut mother plants and the uncut mother plants was 16 times more in SDP than FDP. Production of healthy seed yam tuber is possible using healthy mother plants for vine cuttings

Expected responses to selection for resistance to the pink stem borer (Sesamia calamistis Hampson) and the sugarcane borer (Eldana saccharina Walker) in two maize populations

Progenies from two maize populations, one white-grained (DMR ESR-W) and the other yellow (DMR ESR-Y) were evaluated under artificial infestation with two borer species (Sesamia calamistis and Eldana saccharina) in two seasons to predict responses and correlated responses to selection for resistance to stem borers. Correlations between grain yield and most agronomic parameters were significant. There were negative correlations between grain yield and damage parameters in both maize populations. The highest genotypic correlation coefficient was observed between grain yield and stem tunneling (rg = -0.52) in DMR ESR-Y, and with stalk breakage (rg = -0.67) in DMR ESR-W. A Rank Summation Index (RSI) generated using plant aspect, grain yield, stem tunneling, leaf feed¬ing and tolerance had positive phenotypic correlations with damage parameters, but negative relationship with agronomic traits. All agronomic parameters including grain yield will increase with selection. Grain yield increase of about 210 kg/ha will be obtained per generation in DMR ESR-W using two seasons to complete a cycle, but a relatively low increase (73 kg ha-1) is expected in DMR ESR-Y. Response from single trait selection was better than from RSI in DMR ESR-Y, but reverse was the case in DMR ESR-W. Correlated responses to selection showed that direct selection for most of the traits would be better than indirect selection through any other trait. Appreciable progress is expected from selection for improvement of the maize populations for resistance to the two borer spe¬cies, although progress from selection may be slow

Tropical root crops : root crops and the African food crisis; proceedings of the Third Triennial Symposium of the International Society for Tropical Root Crops - Africa Branch, held in Owerri, Nigeria 17-23 Aug. 1986

Meeting: International Society for Tropical Root Crops - African Branch, Triennial Symposium, 17-23 Aug. 1986, N

Agricultural Nematology in East and Southern Africa : Problems, Management Strategies and Stakeholder Linkages

This is the peer reviewed version of the following article: Herbert Talwana, et al, ‘Agricultural nematology in East and Southern Africa: problems, management strategies and stakeholder linkages’, Pest Management Science Vol. 72 (2): 226-245, February 2016, which has been published in final form at http://dx.doi.org/10.1002/ps.4104. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. © 2015 Society of Chemical Industry.By 2050, Africa’s population is projected to exceed two billion. Africa will have to increase food production more than 50% in the coming 50 years to meet the nutritional requirements of its growing population. Nowhere is the need to increase agricultural productivity more pertinent than in much of sub-Saharan Africa where it is currently static or declining. Optimal pest management will be essential, because intensification of any system creates heightened selection pressures for pests. Plant-parasitic nematodes and their damage potential are intertwined with intensified systems and can be an indicator of unsustainable practices. As soil pests, nematodes are commonly overlooked or misdiagnosed, particularly where appropriate expertise and knowledge transfer systems are meager or inadequately funded. Nematode damage to roots results in less efficient root systems that are less able to access nutrients and water, which can produce symptoms typical of water or nutrient deficiency, leading to misdiagnosis of the underlying cause. Damage in subsistence agriculture is exacerbated by growing crops on degraded soils and in areas of low water retention where strong root growth is vital. This review focuses on the current knowledge of economically important nematode pests affecting key crops, nematode control methods, and the research and development needs for sustainable management, stakeholder involvement and capacity building in the context of crop security in East and Southern Africa, especially Kenya, Tanzania, Uganda and Zimbabwe.Peer reviewe

Chikungunya as a cause of acute febrile illness in southern Sri Lanka

10.1371/journal.pone.0082259PLoS ONE812-POLN

Variability for resistance to the pink stem borer (Sesamia calamistis Hampson) and the sugarcane borer (Eldana saccharina Walker) in two tropical maize populations

A set of 100 S1 plants were selected from a white and yellow maize population to generate both full-sib and half-sib progenies using North Carolina Design II (NCD II) mating scheme. The 250 progenies generated in each population were evaluated under artificial infestation with two borer species (Sesamia calamistis and Eldana saccharina) at two locations in two seasons to determine levels of genetic variability for improvement purposes. There were wide ranges for most of the traits studied in both maize populations. Plant height and grain yield were significantly reduced with mean grain yield loss being between 25 and 30%. In the white population, additive variance was larger than dominance variance for grain yield, days to 50% silking, stalk breakage and ear per plant, but for the yellow counterpart, additive variance was larger for plant height, ear per plant, leaf feeding and cob damage. None of the gene actions was important for dead heart. Narrow-sense heritability was low to moderate for the resistance parameters. It ranged from 1.45% for leaf feeding to 40.6% for stalk breakage in the white population, and from 3.80% for leaf feeding to 40.1% for cob damage in the yellow population. Heritability for grain yield was 37.6% in the white population but much lower (10.5%) in the yellow population. Although, heritability was low to moderate for the traits studied, the wide ranges and moderate additive variances obtained suggest that substantial genetic variability exist in the two maize populations for reasonable improvement to be made. Breeding scheme that capitalizes on both additive and dominance gene action would be effective for improving the populations for stem borer resistance and grain yield

Optimized protocol for in vitro pollen germination in yam (Dioscorea spp.)

Open Access Journal; Published online: 18 Apr 2021Yam (Dioscorea spp.) plants are mostly dioecious and sometimes monoecious. Low, irregular, and asynchronous flowering of the genotypes are critical problems in yam breeding. Selecting suitable pollen parents and preserving yam pollen for future use are potential means of controlling these constraints and optimizing hybridization practice in yam breeding programs. However, implementing such procedures requires a robust protocol for pollen collection and viability testing to monitor pollen quality in the field and in storage. This study, therefore, aimed at optimizing the pollen germination assessment protocol for yam. The standard medium composition was stepwisely modified, the optimal growth condition was tested, and in vivo predictions were made. This study showed that the differences in yam pollen germination percentage are primarily linked to the genotype and growing conditions (i.e., medium viscosity, incubation temperature, and time to use) rather than the medium composition. The inclusion of polyethylene glycol (PEG) in the culture medium caused 67–75% inhibition of germination in D. alata. Although the in vivo fertilization was dependent on female parents, the in vitro germination test predicted the percentage fruit set at 25.2–79.7% and 26.4–59.7% accuracy for D. rotundata and D. alata genotypes, respectively. This study provides a reliable in vitro yam pollen germination protocol to support pollen management and preservation efforts in yam breeding