Crop Science Research Papers/Topics

Seasonal dynamics and alternate hosts of thrips transmitted Iris yellow spot virus in Kenya

Abstract: Thrips-transmitted Iris yellow spot virus (IYSV) (Family Tospoviridae, Genus Orthotospovirus) is a major constraint to onion (Allium cepa L.) production in Kenya. Determining seasonal patterns of the vector and alternate hosts of the virus could help onion farmers plan Integrated Pest Management strategies; while allowing them to move away from calendar-based applications of insecticides. The objective of this study was to determine the distribution, seasonal variations and alterna...

Organisation du pool génique de Vigna unguiculata (L.) Walp. : croisements entre les formes sauvages et cultivées du niébé

Abstract: Organization of the genic pool of Vigna unguiculata (L.) Walp.: crosses between the wild and cultivated forms of cowpea. Cowpea (Vigna unguiculata (L.) Walp.) gene pool organization is studied on the basis of intra-specifi c crossing between cultivated (cv-gr. Unguiculata, cv-gr. Bifl ora) and wild forms of the species (var. spontanea, subsp. alba, subsp. stenophylla, subsp. pawekiae, subsp. baoulensis). The rate of crosses success, the rate of the obtained pods fruitfulness and th...

Reduction of initial occurrence of rice blast (Pyricularia oryzae) inocula on seeds by microbial and hot water seed treatments

Abstract: Rice blast disease resulting from infected rice seed can be avoided by using treated seeds. Seed treatment using chemical fungicide has many limitations such as development of resistance to pathogens, damage to the natural environment and the health of farmers and consumers. Such limitations have raised the need for alternative non-chemical seed treatment methods such as antagonist microbial agents and hot water. Laboratory and the screen house experiments were carried out with the...

Insect pollination and pollinator supplementation enhances fruit weight, quality, and marketability of avocado (Persea americana)

Abstract: Avocado is a pollinator-dependent crop rich in fiber, monounsaturated oils, vitamins, and minerals, which is seeing an increase in global demand. While some studies have shown that insect pollination improves avocado fruit set, the effects of pollinators on fruit quality and the nutritional profile remain unclear. Furthermore, it remains untested whether a potential pollination deficit can be compensated by the supplementation of farms with extra pollinators. We quantified the cont...

Management options for Rice Stem borers in irrigated low land rice ecosystems in Tanzania

Abstract: Studies were carried out to establish the role and significance of rice stem borers as pests of rice crop in irrigated low land rice ecosystems in Tanzania; and to evaluate the effectiveness of some management options against the pest. A survey by means of structured questionnaire was init ially used to assess the farmer’s perception on rice stem borers and their management practices in three wards of Kilombero district in Morogoro Region, namely, Mkula, Sanje and Signali. This w...

Analysis of Chemical Composition of Cowpea Floral Volatiles and Nectar

Abstract: Cowpea is one of the 14 species of grain legumes. It rewards insects by producing nectar and it advertises to the pollinators by producing floral volatiles. The volatiles act as cues that guide insect pollinators in terms of pollen and nectar. Floral volatile quality also influences the efficiency of pollination. Genetic manipulations involving selection of varieties with high quality floral volatiles and nectar can therefore increase pollination efficiency and hence cowpea yields....

Oviposition and Feeding Allelochemicals for Chilo partellus from Sorghum and Maize Cultivars; Bioassay, Isolation and Characterization

Abstract: A study was carried out to isolate and identify the chemicals from sorghum and maize that determine the oviposition and feeding responses, respectively, of the moth and larvae of Chilo partellus a serious pest of these crops. Studies were carried out on a resistant and a susceptible cul ti var of maize (MP 704 resistant; INBRED A susceptible) as well as sorghum (IS 1044 resistant; IS 18363 susceptible). The allelochemicals were extracted sequentially with petroleum ether, ethyl ace...

Evaluation of Growth and Yield Responses of Taro (Colocasia Esculenta) to Plant Spacing and Npk Fertilizer in the Plains of Nsukka, Nigeria.

ABSTRACT Two field experiments were conducted in 2008 and 2009 cropping seasons at the linkage farm of the University of Nigeria, Nsukka to evaluate growth and yield response of (Taro) Colocasia esculenta to plant spacing and NPK fertilizer on the plains of Nsukka with the objectives of identifying best performing cultivar, optimum plant spacing and NPK fertilizer rate. Experiment one was laid out in a 3x5 factorial in Randomized Complete Block Design (RCBD) in which Factor A is plant spacin...

Studies on the Genetic Pathway and Selection Response for Increased Fruit Size and Yield in Tomato (Solanum Species) Using a Modified Three-Way Cross

ABSTRACT Modified three-way crosses involving advanced interspecific tomato hybrids (W x R), (R x W) and (W x T) at F12 generation and commercially cultivated tomato varieties namely Supersteak (S), Beef (Florida) (BF) and Plumb (Rio grande) (PR) were made to generate F1 hybrids. The F1 hybrids were crossed to both the pollen and seed parents to produce the backcrosses and were also allowed to random mate to produce the F2 and F3 populations. The parents, F1s, F2s, F3s, and backcrosses were ...

Juvenile Morphological Markers for Maleness in Fluted Pumpkin (Telfairia Occidentalis Hook F.)

ABSTRACT  Six hundred seeds extracted from nine pods of fluted pumpkin (Telfairia occidentalis Hook F.) were sown in the field in 2004 and 2005 to determine the juvenile morphological markers for maleness. The results showed a significant difference (P < 0.05) between the male and female fluted pumpkin with respect to days to tendril emergence. The mean number of days to tendril emergence for the males was 19 (in 2004) and 20 (in 2005) days after planting while that of the females was 47 (in...

Studies on Aspects of Reproductive Biology and Pod Yield in Bambara Groundnut (Vigna Subterrenea (L.) Verdc)

ABSTRACT Two field experiments were conducted in April and August, 2007 cropping season at the Department of Crop Science research farm, University of Nigeria, Nsukka, to evaluate the pollen germination potentials, rate of pollen tube growth, floral, agronomic and yield attributes of thirteen bambara groundnut cultivars. The first experiment (early planting) was in April and the second (late planting) was in August 2007. The results obtained showed that 10 genotypes had significant effect on...

Management of Fungal Diseases Associated with Germination and Growth of Moringa Oleifera Lamarck with Botanicals

ABSTRACT  Studies were carried out at the Department of Crop science, University of Nigeria Nsukka (UNN) to evaluate botanicals control of diseases associated with growth and germination of Moringa seeds. Five accessions of Moringa seeds collected from Imo, Enugu, Kogi, Plateau and Kaduna states of Nigeria were used. The following experiments were carried out: seed viability test, isolation of fungal pathogens, determination of phytochemicals, in vitro control of the pathogens with six botan...

Planting Time, Spray Regime, Disease Expression and their Impacts on Six Cucumber Lines in a Derived Savanna Agroecology of Nsukka, Southeastern Nigeria.

ABSTRACT  Cucumber (Cucumis sativus L.) belongs to the Cucurbitaceae family. It is a major vegetable crop worldwide and develops rapidly, with a shorter time from planting to harvest than most crops. It is a monoecious annual climber or creeper that has been cultivated for over 3,000 years and is still widely cultivated today. The fruit is soft, succulent with high water content, roughly cylindrical and elongated with tapered ends. The plant shades one another, being allowed to creep on the ...

Studies on Fertilizer Nitrogen and Cutting Management of Sown Grass and Legume Pastures in Pure and Mixed Swards.

ABSTRACT  Three field experiments were conducted at the Teaching and Research Farm of the Department of Crop Science, Faculty of Agriculture, University of Nigeria, Nsukka. In the first experiment, the effects of fertilizer-N application and cutting management on establishment, growth and yield of guinea grass (Panicum maximum) were investigated. The experiment was a 4 x 4 factorial laid out in a randomized complete block design with three replications. Treatments comprised four levels of Ni...

Utilization of Wild Tomato Relative for the Development of Improved Tomato Lines for High Humidity Environment.

ABSTRACT An effort to obtain a tomato cultivar that would adapt to high temperature and high humidity condition in the southern part of Nigeria in order to increase tomato yield in this part of the country has been in progress for the past nine years (2000-2008).The research was carried out at the Faculty of Agriculture Research Farm, University of Nigeria, Nsukka located in the derived savanna zone latitude 0.6o 52, N, longitude 07o 24, E, 447.26 m altitude. Three cultivated tomato varieties...


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