Welcome to the International Institute of Tropical Agriculture Research Repository
Journal and Journal Articles: Recent submissions
Now showing items 1661-1680 of 5273
-
Genotype by environment interaction in Musa germplasm revealed by multisite evaluation in subSaharan Africa
(1995)A multilocational evaluation trial comprising 18 Musa genotypes was carried out from 1991 to 1994 in three representative locations in the humid forest (Onne, Nigeria and M'Balmayo, Cameroon) and the Forest-savanna Transstion (Ibadan, Nigeria) Zones of West and Central Africa. The main objective was to evaluate the performance of improved Musa germplasm under different agro-ecological conditions, thereby assessing the genotypes-by-environment interaction (GxE) for specific traits and yield stability. ... -
Transient gene expression in transformed banana (Musa cv. Bluggoe) protoplasts and embryogenic cell suspensions
(1995)In order to introduce currently-available genes with agronomical value into banana, two genetic transformation protocols have been optimized. Firstly, regenerable protoplasts isolated from embryogenic cell suspensions of the cultivar Bluggoe have been used for the introduction of several chimaeric uidA gene constructs by electroporation. With the inclusion of polyethylene glycol and heat shock, the frequency of transiently expressing protoplasts reached 1.8% as shown by an in situ β-glucuronidase ... -
Variability in storage potential of banana shoot cultures under medium term storage conditions
(1995)Shoot cultures of 401 banana clones were conserved under slow growth conditions (16±1°C, 25μmol m−2 s−1). Storage duration-defined as 60% survival time of 20 shoot cultures of a clone-averaged 334 days. However, large differences occurred among the different genomic (sub)groups and even within the same (sub)group. East-African highland bananas and non-plantain AAB bananas can be stored for significantly longer periods. Shoot tip cultures of another 41 banana clones conserved at higher ambient ... -
Phenotypic diversity and pattern of variation in West African plantains (Musa spp. AAB group)
(1995)Plantains (Musa spp., AAB group) are an important food crop and an integral component of the farming systems in the lowland humid forest zone of West and Central Africa. A group of 24 plantain cultivars, representing the major variability in West Africa, was evaluated for nine quantitative characters. The association between growth and yield parameters in this African plantain germplasm was examined to determine if the pattern of quantitative variation in inflorescence and vegetative traits agreed ... -
Genetic transformation in Musa species (Banana)
(1995)The term banana is meant throughout this chapter to cover dessert and cooking bananas as well as plantains. With an estimated total production of more than 76 million tons in 1992 (FAO 1993), banana is the no. 1 fruit crop in the world. Ninety-nine percent of world's annual production is cultivated in more than 110 developing countries. Approximately 90% of the total production is used for domestic consumption: banana is staple food for at least 400 million people. The remaining 10% product entering ... -
Changes in annual, seasonal and monthly rainfall in Nigeria during 1961-90 and consequences to agriculture
(1995)The focus of this study is to provide baseline data for agricultural development activities in Nigeria, with emphasis on understanding the dynamics of spatial and temporal change in annual, seasonal and monthly rainfall during the past 30 years (1961-1990), using daily rainfall data. It was found that annual rainfall has declined in Nigeria over both time and space. The rainfall decline is unprecedented in duration and seasonal expression. The greatest change occurred in the onset of the rainy ... -
Soil N, P, and land use efficiency under cassava/sweet potato intercropping system in Tanzania
(1995)Cassava sweet potato intercropping experiments were carried out at Ukiriguru (semiarid zone), Tanzania during the period from 1989-91. Four cassava varieties used were, Msitu Zanzibar, Alpim valenca, Mzimbirala and Liongo control. The second experiment tested four cassava planting densities, 6666, 10000, 13333 and 20000 plants per hectare. In the two trials, cassava was planted with single or double rows of sweet potato on the same ridge. Basal dressing of inorganic fertilizers at the rate of 60 ... -
Early nitrogen fixation and utilization in Albizia lebbeck, Leucocephala, and Gliiricidia sepium using nitrogen 15N labeling
(1995)High nitrogen (N2)‐fixing potential is a desirable characteristic for any candidate hedgerow tree. Thus a study was conducted to evaluate Albizia lebbeck as a N2‐fixing tree in comparison to Gliricidia sepium and Leucaena leucocephala currently used in alley cropping. Nitrogen fixation and utilization were assessed in a screenhouse at four months after planting by the 15N dilution technique using Senna siamea as the non N2‐fixing reference. A. lebbeck accumulated significantly more N than L. ... -
Phosphorus and liming effects on early growth of selected plant species grown on an Ultisol
(1995)A series of pot experiments were conducted to test the effect of phosphorus (P) application and liming on early growth performance of Zea mays, Mucuna pruriens and nine woody species (Albizia ferruginea, Cajanus cajan, Dactyladenia barteri, Dalbergia sissoo, Enterolobium cyclocarpum, Flemingia macrophylla, Gliricidia sepium, Leucaena leucocephala, and Pentacletra macrophylla) on an Ultisol. Low reponse to liming and high response to P application were observed in this trial. Early top growth of ... -
Measuring host finding capacity and arrestment of natural enemies of the cassava mealbug, Phenacoccus manihoti, in the field
(1995)In uninfested fields, 80 cassava tips were artificially infested with 0, 1, 2, 4, 8, 16, 32, or 64 third instars, and 20 or 100 eggs of cassava mealybug, Phenacoccus manihoti Matile‐Ferrero (Hom., Pseudococcidae). Another 80 uninfested tips served as a control. Tips were arranged in a circle of 28 m diameter, in the centre of which the following exotic natural enemies of P. manihoti were released: Apoanagyrus (Epidinocarsis) lopezi De Santis and A. diversicornis (Howard) (Hym., Encyrtidae), ... -
Future prospects for cassava root yield in sub Saharan Africa
(1995)Primary data collected over a wide area in Africa show that average cassava root yield is not declining as the population increases because the land is being cultivated more intensively in response to demographic pressures. Although fallow periods are becoming shorter, organic manuring, improved market infrastructures and the use of purchased inputs such as labour compensate for this. The yields of improved cassava varieties in Nigeria show that technology can be relied upon to raise production ... -
Effects of prey deprivation on life table attributes of Neoseiulus idaeus Denmark and Muma (Acari: phytoseiidae)
(1995)Reproductive responses of Neoseiulus (= Amblyseius) idaeus Denmark and Muma ovipositing females were measured under three dietary regimes consisting of Mononychellus tanajoa (Bondar) or Oligonychus gossypii (Zacher) combined with specific periods (24, 48, 72, and 96 h) of starvation or periods of the same duration in which only cassava exudate was provided. These periods were applied after the females had laid at least one egg. The control treatments consisted of predators supplied with a continuous ... -
Assessement of crop loss in cowpea (Vigna unguiculata [L] Walp) caused by Sphaceloma sp., causal agent of scab disease
(1995)IT 84S-2140 and IT 85F-1517 (cowpea varieties) susceptible to scab disease caused by Sphaceloma sp. were treated with severely infected cowpea plants in 1989 and 1990 field trials. Different levels of disease intensity were generated by treatment with benomyl using two different methods of application: varying the frequency of application from 4- to 35-day intervals resulted in grain losses ranging between 25–70% in 1989 and 35–50% in 1990. When the concentration of benomyl was varied at a 10-day ... -
Sustainability of African smallholder farming systems: case study of highland areas of Central Africa
(1995)This article shows that the measurement of the sustainability of a production system should be conducted using a systems approach which corresponds best with the social, economic and bio-physical parameters of the African smallholder farming system. The case study shows that the system as a whole is not sustainable, that improvements would be possible if the system were made more efficient, and that it is vital to introduce new technologies if complete sustainability is the ultimate aim. It would ... -
Effect of temperature, humidity and photoperiod on mortality of Mononychellus tanajoa (Acari: tetranychidae) infected by Neozygites cf. floridana (Zygomycetes: entomophthorales)
(1995)The effect of temperature, humidity and photoperiod on the development of Neozygites cf. floridana (Weiser and Muma) in the cassava green mite, Mononychellus tanajoa (Bondar) was studied in the laboratory. Dead infected mites began to appear 2.5 days after inoculation. At 33 and 28°C peak mortalities were higher and occurred earlier (after 2.5 days), than at 23 and 18°C. Mean LT50 (time for half the infected mites to die) decreased with increasing temperature as follows: 3.9, 3.0, 2.9 and 2.5 days ... -
Evaluation of cowpea genotypes for field resistance to the legume pod borer, M. testulalis in Nigeria
(1995)Eighteen cowpea cultivars were screened for resistance to the legume pod borer, Maruca testulalis under field conditions at two locations (Mokwa and Ibadan) in Nigeria under unprotected and two types of insecticide protection levels. Unprotected plots gave zero yield due to their exposure to the entire cowpea pest complex. Plots that received a mixture of Cypermethrin and dimethoate (as Cymbush Super ED®) treatment were better (P < 0.05) than plots treated with monocrotophos (as Nuvacron 40EC) in ... -
Effect of the parthenocarpy gene P1 and ploidy in bunch and fruit traits of plantain and banana hybrids
(1995)Plantain and banana (Musa spp. AAB and AAA groups) are perennial giant herbs of the tropics which develop parthenocarpic fruits. At least three independent but complementary dominant genes control vegetative parthenocarpy in Musa. One of these genes, P1 segregates in euploid hybrid progenies derived from crosses between triploid 'French' plantains and a wild nonedible diploid banana. Linear correlation and regression analyses revealed that bunch weight and fruit weight and size were positively ...
