IITA Bibliography System: Recent submissions

Now showing items 1881-1900 of 8126

    • Can introduced and indigenous rhizobial strains compete for nodule formation by promiscuous soybean in the moist savanna agroecological zone of Nigeria? 

      Okogun, J.A; Sanginga, N. (2003)
      Promiscuous soybean lines have been bred on the basis that they would nodulate freely without artificial inoculation. However, our recent studies have demonstrated that the indigenous rhizobia are not able to meet their full nitrogen (N) requirement. Rhizobia inoculation might be necessary. We examined the competition for nodule formation among native Rhizobia spp. and two inoculated Bradyrhizobia strains (R25B indigenous strain and a mixture of R25B+IRj 2180A indigenous strain from soybean lines ...

    • Relationship between dormancy and its release and external factors in tubers of water yam (Dioscorea alata L.) 

      Park, B.J.; Onjo, M.; Tominaga, S.; Shiwachi, H.; Hayashi, M. (2003)
      To analyze the mechanism of dormancy in tubers of water yam (Dioscorea alata L.), we studied the relationship between external factors and dormancy and its release in tubers. Several strains of water yam that have been introduced into Japan from Southeast Asia and Oceania were grown in Kagoshima, Japan. Dormancy period ranging from 2 to 4 months in length (from harvest to sprouting), has been observed in 48 strains that were tested at 25 ℃. It was found that the duration of the dormancy period ...

    • An international public partnership for genetic enhancement of cowpea using a holistic approach to biotechnology 

      Ortiz, R. (2003)
      Cowpea is the most important product in African dryland agriculture. Its protein-rich grains are the main product of the crop, which are commonly eaten in different forms by rural and urban peoples. African farmers growing cowpea in their fields often harvest low yields because many biotic and abiotic factors affect the crop. Cultural practices, together with genetic manipulation through breeding (including biotechnology), can ameliorate yield-limiting factors affecting the farming of cowpea in ...

    • Dynamics of refuge use: diurnal vertical migration of predatory and herbivorous mites within cassava plants 

      Onzo, A.; Hanna, R.; Zannou, I.; Sabelis, M.W.; Yaninek, J.S. (2003)

    • Diploid banana hybrids TMB2x51051 and TMB2x91283 with good combining ability, resistance to black sigatoka and nematodes 

      Tenkouano, A.; Vuylsteke, D.; Okoro, J.; Makumbi, D.; Swennen, R.; Ortiz, R. (2003)

    • iMap: a databasedriven utility to integrate and access the genetic and physical maps of maize 

      Fang, Z.; Cone, K.; Sanchez-Villeda, H.; Polacco, M.; McMullen, M.; Schroeder, S.; Gardiner, J.; Davis, G.; Havermann, S.; Yim, Y.; Vroh, I.; Coe, E.; Bi, I.V. (2003)
      Motivation: Because of the unique biological features, a bioinformatic platform for the integrated genetic and physical map of maize is required for storing, integrating, accessing and visualizing the underlying data. Results: The goal of the Maize Mapping Project is to develop a fully integrated genetic and physical map for maize. To display this integrated map, we have developed iMap. iMap has three main components: a relational database (iMapDB), a map graphic browser (iMap Viewer) and a search ...

    • Recent progress on cowpea improvement 

      Singh, B.B.; Hartmann, P.; Fatokun, C.; Tamo, M.; Tarawali, S.; Ortiz, R. (2003)

    • Biology and integrated pest management for the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) 

      Gold, C.S.; Pena, J.E.; Karamura, E.B. (2003)
      The banana weevil Cosmopolites sordidus (Germar) is the most important insect pest of bananas and plantains (Musa spp.). The larvae bore in the corm, reducing nutrient uptake and weakening the stability of the plant. Attack in newly planted banana stands can lead to crop failure. In established fields, weevil damage can result in reduced bunch weights, mat die-out and shortened stand life. Damage and yield losses tend to increase with time. This paper reviews the research on the taxonomy, distribution, ...

    • Grouping locations for efficient cassava evaluation in Malawi 

      Mkumbira, J.; Mahungu, N.M.; Gullberg, U. (2003)
      Cassava, a crop widely adapted in the tropics, has the important attribute of withstanding adverse environmental conditions better than do many other staple crops. The performance of an individual genotype, however, is influenced by the environment in which it grows. In Malawi, the heterogeneity of agro-ecologies requires the cumbersome and costly assessment of new cassava genotypes at many sites. This study was conducted, therefore, to test the feasibility of selecting only a few locations for ...

    • Effects of mulch location on banana weevil, nutrients, soil water, and biomass in banana 

      McIntyre, B.D.; Gold, C.S.; Ssali, H.; Riha, S.J. (2003)
      Major constraints to banana (Musa spp., genome group AAA) production, a dietary staple for over 70 million people in sub-Saharan Africa, are pest infestations, poor nutrition and inadequate water. Although mulch can improve soil water and nutrient status, many farmers believe it also promotes the proliferation of banana weevil (Cosmopolites sordidus), one of the most serious banana pests. In this study, we evaluated the effects of mulch location (mulch to base of banana pseudostem; mulch recessed ...

    • Agronomic performance of maize (Zea mays L.) breeding lines derived from a low nitrogen maize population 

      Kamara, A.Y; Kling, J.G; Menkir, A.; Ibikunle, O. (2003)
      Eighteen S1 lines of maize (Zea mays L.) derived from a low nitrogen tolerant pool and two inbred lines were evaluated for agronomic performance under moderate N conditions in the southern Guinea savannah of Nigeria. Generally, the breeding lines differed in yield, growth, vertical rootpulling resistance, N-uptake and N-use efficiency. Breeding lines with high vertical root-pulling resistance took up more N and utilized it more efficiently. They also showed better agronomic performance and recorded ...

    • Root characteristics in cowpea related to drought tolerance in seedlings 

      Matsui, T.; Singh, B.B. (2003)
      Cowpea (Vigna unguiculata) has relatively higher drought tolerance than other legume crops. It is widely grown in semi-arid regions, particularly in West Africa. One objective of the present study was to determine the effects of soil moisture stress on the length, dry matter and distribution of the roots of two cowpea varieties with different drought tolerances. Another objective was to evaluate the pin-board root-box as a method for identifying the role of root characteristics in drought tolerance. ...

    • The influence of drought stress on growth, yield, and yield components of some maize genotypes 

      Kamara, A.Y.; Menkir, A.; Badu-Apraku, B.; Ibikunle, O. (2003)
      The risk of drought is high in the Sudan savannah zone of West and Central Africa because rainfall in this area is unpredictable in quantity and distribution. Thus, improved maize genotypes tolerant to drought could stabilize maize grain yield in this zone, where recurrent drought threatens grain production. Six maize genotypes, two each of hybrids, open-pollinated varieties (OPVs) and landraces, were evaluated for tolerance to terminal water deficit before flowering. Water deficit significantly ...

    • Effects of photo regime on the timing of male responses to sex pheromones in male Cnaphalocrocis medinalis (Lepidoptera: Crambidae) 

      Kawazu, K.; Adati, T.; Tatsuki, S. (2003)
      We examined the effect of moth age and photoregime on the timing of male response to sex pheromones in male Cnaphalocrocis medinalis. The responsiveness of males varied with age, increasing up to 3-days and then remaining constant to 7-days. In male responses to the pheromone throughout the scotophase under five different photoregimes, it was shown that the time to reach the maximal response level after lights-off was rather constant (ca. 4 h), regardless of the duration of the scotophase in a ...

    • Characterization of legume cover crops for weed suppression in the moist savanna of Nigeria 

      Ekeleme, F.; Akobundu, I.O.; Fadayomi, R.O.; Chikoye, D.; Abayomi, Y.A. (2003)
      Multilocational characterization of selected herbaceous and shrub legumes was carried out over a 3-yr period at lowland and midlatitude sites in the moist savanna agroecological zone in Nigeria where a south-north gradient exists for rainfall, length of growing season, and insolation. One study site each was located in coastal-derived savanna (DS), southern Guinea savanna (SGS), and northern Guinea savanna (NGS). A fourth site was located in the plateau of the NGS. Only one legume cover crop, ...

    • Cybrids and tetrad sterility for developing true potato seed hybrids 

      Golmirzaie, A.M.; Tenorio, J.; Serquen, F.; Ortiz, R. (2003)
      Potato cybrids result from the fusion between cytoplasm and nuclear gene donors. Such genetic materials are an alternative means to broaden the breeding pool by non‐sexual gene transfer. Tetrad pollen sterility provides also another source of male sterility with some potential for true potato seed breeding. The objective of this research was to investigate cybrid‐derived offspring for both agronomic and reproductive characteristics in two contrasting Peruvian locations, and to examine new exotic ...

    • Potential of ethyleneproducing pseudomonads in combination with effective N2fixing bradyrhizobial strains as supplements to legume rotation for the control of Striga hermonthica 

      Ahonsi, M.O.; Berner, D.K.; Emechebe, A.M.; Lagoke, S.T; Sanginga, N. (2003)
      Striga hermonthica (Del.) Benth. is an obligate, root-parasitic, flowering plant that limits cereal production in sub-Saharan Africa.Successful control depends on eliminating its seed reserves in soil, thereby preventing parasitism. Striga hermonthica seeds germinate only if adequately conditioned and exogenous stimulant initiates ethylene production within the seed, or if ethylene is directly supplied to the conditioned seed.Since S. hermonthica is an obligate root parasite, stimulating the seeds ...

    • Amelioration de la gestion des sols par lintroduction de legumineuses dans les systemes cerealiers des savannes africaines 

      Carsky, R.J.; Douthwaite, B.; Manyong, V.M.; Sanginga, N.; Schulz, S.; Vanlauwe, B.; Diels, J.; Keatinge, J.D.H. (2003)
      Lessons for appropriate soil management technology generation for the savannas and their application to the grain legume-cereal rotation system There are many legume-based techno logies capable of regenerating soi l ferti lity but few are being adopted by fa rmers in West Africa . At the Tn ternationa l Institute of Tro pica l Agriculture (TTTA) we found that alley cropping and cover cropping systems are biologica ll y sustainable but have low adoption by farmers in the medium term. Negacive ...

    • Plantparasitic nematodes associated with root and tuber crops in Uganda 

      Coyne, D.L.; Talwana, H.; Maslen, N.R. (2003)
      In a nematode survey of eight commonly grown root and tuber crops (cassava, sweet potato, potato, yam, tannia, taro, carrot and turmeric) from 430 fields in Uganda, 69 species of plant-parasitic nematodes representing 28 genera were extracted from soil and roots. About twice as many nematode species were recovered from soil (64) as from roots (36), while 32 species were found only in soil and four species only in roots, usually in mixed populations. Meloidogyne spp. (root-knot nematodes) were the ...

    • Field evaluation of cowpea cultivars (Vigna unguiculata L Walp.) for resistance to flower thrips (Megalurothrips sjostedti Trybom) (Thysanoptera: Thripidae) 

      Alabi, O.Y.; Odebiyi, J.A.; Jackai, L.E.N. (2003)
      Ten cowpea cultivars were screened for resistance to flower bud thrips, Megalurothrips sjostedti, in replicated field trials. Resistance was evaluated by measuring differences in populations and visual damage on the cultivars. Statistical correlation was employed to assess the degree of association between damage indices and thrips population in the cultivars for each season. In the first season cultivars were conveniently grouped into three, using damage indices and thrips populations size. In ...