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Asgedom S.,Hamelmalo Agricultural College | Asgedom S.,Wageningen University | Struik P.C.,Wageningen University | Heuvelink E.P.,Wageningen University | Araia W.,Hamelmalo Agricultural College
African Journal of Agricultural Research | Year: 2011

Tomato is an important vegetable in Eritrea, grown across the entire country. Yields in Eritrea are comparatively low, due to agronomic, institutional and market constraints. We carried out a survey throughout the country based on a participatory rural appraisal, discussion groups and interviews with staff members of the Ministry of Agriculture. Results showed that farmers preferred varieties with a prolonged harvesting period and a long storage life unless other varieties are better yielding and can immediately be marketed. However, their knowledge on varieties is limited while maintaining their own seeds. Seedlings are established in nurseries and subsequently transplanted once they have reached a height of 10 to 15 cm. Spacing, staking, pruning and irrigation are important aspects of proper crop management. Flower abortion is common in some areas and the crop is affected by several diseases and pests. The harvesting takes place over a prolonged period and timing of harvest of individual fruits is based on skin colour. There are significant price differences based on size grade. Seasonality of the crop causes problems with marketing and price fluctuation. It is recommended to improve the farmer's knowledge on variety characteristics, to improve the seed systems and train the farmers in improved crop management. ©2011 Academic Journals.


Jeyaramraja P.R.,Hamelmalo Agricultural College | Thushara S.S.,Karpagam Arts and Science College
Photosynthetica | Year: 2013

Responses of drought-tolerant (DT) and drought-susceptible (DS) pot-grown groundnut (Arachis hypogaea L.) varieties to changes in leaf relative water content (RWC) were studied. Water stress (WS) was imposed on 30-day-old plants for 2 weeks. Leaf RWC decreased significantly under WS conditions with simultaneous decrease in net photosynthetic rate (P N) and stomatal conductance (g s). Even though no significant difference was observed between DT and DS varieties with regard to RWC, DT varieties were able to maintain significantly higher P N than DS varieties. Higher values of water use efficiency (WUE) were also observed in DT varieties during WS conditions. The decline in P N due to WS could be attributed to both reduction in g s (i.e. stomatal limitation) and to reduction in chlorophyll content (Chl). No significant difference in leaf area index (LAI) was found between DT and DS types and LAI was not reduced by WS. Significant differences were found among the studied groundnut varieties, but not between DT and DS types, in terms of root, aboveground, and total dry mass. These growth parameters significantly decreased under WS conditions. Based on the results, a sequence of physiological responses in groundnut crop subjected to WS was postulated. © 2013 Springer Science+Business Media Dordrecht.


Aregay F.A.,Northwest University, China | Aregay F.A.,Hamelmalo Agricultural College | Zhao M.,Northwest University, China | Li X.,Northwest University, China | And 2 more authors.
Sustainability (Switzerland) | Year: 2016

This paper analyzes public awareness and perception about current issues of environmental and water resources in China in comparison to the socio-economic issues. The ranking, Likert scale, and ordered logit analysis were applied to data from 1773 sample residents in northwest China. The results show that the residents rank the degradation of the ecological environment and water resources as the most important issue, and education, political involvement, gender, employment, and residential location play significant roles in explaining the observed differences in concern. Of the possible environmental and water resource restoration policies, residents ranked water quantity and quality, agricultural and industrial water use, erosion control, vegetation restoration, wildlife habitat, animal brooding and migration services, biodiversity landscape, and eco-tourism from one to nine in order of importance, respectively. The results are relevant for policymaking and imply that environmental restoration is a high public demand. Welfare gains from investments in it would be higher or equal to gains from other socio-economic and livelihood activities. Thus, public policies must emphasize restoring and maintaining a sustainable ecological environment. © 2016 by the authors.


Bill M.,University of Pretoria | Bill M.,Tshwane University of Technology | Sivakumar D.,Tshwane University of Technology | Korsten L.,University of Pretoria | And 2 more authors.
Crop Protection | Year: 2014

Avocado fruit has high economic value; however, major post-harvest losses are encountered throughout the supply chain mostly due to anthracnose disease caused by the fungus Colletotrichum gloeosporioides. Increasing consumer concern regarding food safety and demand for organically produced fruits makes it necessary to search for natural environmentally friendly alternative products and processes for the fruit industry; particularly in disease control. Antifungal effects of Gum Arabic (GA) (10%), Aloe vera (AL) (2%), chitosan (CH) (1%) alone or in combination with thyme oil (1%) were investigated invitro. CH+thyme oil and AL+thyme oil [1:1 or 3:1 v/v] showed fungicidal effects while AL, CH, GA and GA+thyme oil [3:1 v/v] showed fungistatic effects on mycelial growth of C.gloeosporioides invitro. CH and AL coatings alone or in combination with thyme oil [3:1 v/v], either as preventative or curative treatments in comparison with commercial treatment (prochloraz, 0.05%) and untreated control were evaluated on incidence and severity (lesion diameter) of anthracnose invivo. Preventative CH+thyme oil treatments significantly reduced the severity of anthracnose (8.9mm) compared to thyme oil (12.7mm), AL+TO (14.4mm), CH (17.8mm), AL (20.6mm), PZ (18.3mm) and untreated samples (34.8mm). As curative method, the CH+thyme oil combination also reduced the severity of anthracnose by at least 4mm compared to the other treatments. The total phenols, polyphenol oxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, chitinase, catalase and superoxide dismutase activities, firmness and flesh colour were also determined. Results showed an increase in peroxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, chitinase, catalase and superoxide dismutase activities and total phenolics with reduced loss of firmness and flesh colour following CH+thyme oil treatments. This investigation recommends CH+thyme oil [3:1 v/v] combination treatment as a suitable alternative to the currently adopted prochloraz applications in controlling anthracnose disease in avocado fruit during storage. © 2014 Elsevier Ltd.


Yohannes T.,National Agricultural Research Institute | Yohannes T.,University of Nairobi | Tesfamichael A.,Hamelmalo Agricultural College | Kiambi D.,African Biodiversity Conservation and Innovations Center | And 10 more authors.
Field Crops Research | Year: 2015

The parasitic weed Striga hermonthica hampers the production of sorghum, the most important cereal crop in Eritrea. This weed has a complex mode of infestation that adapts to many hosts and environments, complicating conventional breeding for resistance, which is the only form of crop improvement available to Eritrean breeders, but has failed. This study aimed at improving resistance against this parasite by transferring 5 Striga resistant Quantitative Trait Loci (QTLs) from resistance donor N13 to Striga susceptible Farmer-Preferred Sorghum Variety (FPSV) Hugurtay from Eritrea. The method involved backcrossing using marker-assisted selection (MAS) and evaluation of the best introgressed lines for Striga resistance in artificially infested fields. Foreground selection was performed with up to 11 polymorphic simple sequence repeat (SSR) markers linked to Striga resistance QTLs, while background selection was conducted in the BC3F2 generation with 27 polymorphic unlinked SSR markers to identify the best recovery of the recurrent parent (RP) genetic background. Out of 84 BC3F3 lines, L2P3-B, L1P5-A and L2P5P35 performed best with respect to both grain yield and reduced Striga infestation. These lines were more resistant to Striga than Hugurtay, but less resistant than N13. The three lines yielded twice as much as N13, with Area Under Striga Number Progression Curve (AUSNPC) values on average 18% higher than that of N13 and 38% lower than that of Hugurtay. This suggests that the introgressed QTLs conferred significant Striga resistance and yield advantage to these BC3F3 backcross progenies under Striga pressure. These lines have good potential for future release and demonstrate that when MAS is available to conventional breeders, even in countries with no genotyping facilities, it is a useful tool for enhancement, expediency and precision in crop improvement. © 2015.

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