Shading effects of intercropping roselle (Hibiscus sabdariffa) genotypes on plant development, assimilate partitioning and leaf nutrient content

An experiment was conducted to determine the effects of shade on plant development, macronutrient and secondary metabolites in roselle (Hibiscus sabdariffa). Three roselle accessions (ZM 5729, ZM 5738 and ZM ZM5748) acquired from the Zambia National Plant Genetic Resource Centre were used and shade was imposed by intercropping roselle with maize (Zea mays). A Split plot design with shade as main plot and genotype as split- plot was used. Nutritional and development parameters were monitored. At 14 weeks shaded plants had about a three-fold decrease in branches numbers compared to unshaded ones. Plant height was higher in unshaded treatments (120 cm) compared to shaded (83 cm). Plant height of ZM 5738 was significantly higher than the other two accessions. Shading reduced dry matter accumulation by almost 75 % across genotypes with about 20 g per plant in shaded treatments and 73 g in unshaded treatments. Nutrient reductions were highest in fat (60.6 %), fibre (48.4 %), protein (37.8 %), and lowest in ash (27.3 %). In terms of strength of partitioning the pattern was: branches ˃ leaves ˃ roots ˃ squares ˃ flowers. The carbohydrate content increased with shading (10.6 %). Vitamin C content was higher in unshaded treatments in comparison with shaded conditions. ZM 5738 had the highest content followed by ZM 5748 and ZM 5729 had the least content. Oxalates which are an anti- nutrition factor increased with shade. The findings showed that there is significant variation among genotypes and in future selections can be made to choose the most productive genotypes.Int. J. Agril. Res. Innov. & Tech. 8 (1): 7-13, June, 201

Comparative effects of jatropha seedcake, chicken and kraal manures on selected soil properties, growth and yield of tomato (Lycopersicon esculentum)

A field trial was conducted to evaluate the comparative effects of jatropha seedcake, chicken and kraal manures on selected soil properties, growth and yield of tomato in Zambia during the cropping season of 2012-13. A Randomized Complete Block Design (RCBD) with four replicates and six treatments, namely- jatropha seedcake (5.0 t ha-1), chicken manure (5.0 t ha-1), kraal manure (5.0 t ha-1), jatropha seedcake (2.5 t ha-1) + chicken manure (2.5 t ha-1), jatropha seedcake (2.5 t ha-1) + kraal manure (2.5 t ha-1) and control (0.0 t ha-1) was used. Soil total N, P, K, Ca, Mg, SOM, soil pH, bulk density, plant height, number of branches, number of fruits plant-1, and mean fruit weight effects were subsequently monitored. Organic manures significantly increased total N, available P, exchangeable K, Ca, Mg, SOM, soil pH, plant height, number of branches, number of fruits, mean fruit weight and yield of tomato compared to the control. Organic manures also significantly reduced soil bulk density compared to the control. Among the organic amendments treated alone, jatropha seedcake gave the highest yield of 28.62 t ha-1 compared to chicken manure (28.20 t ha-1) and kraal manure (27.50 t ha-1). Maximum yield benefits came from a mixture of jatropha seedcake + chicken manure (29.60 t ha-1)and jatropha seedcake + kraal manure (29.00 t ha- 1) which could have been due to balanced proportions of major nutrients required for tomato growth. Jatropha seedcake mostly performed favourably the same or better than chicken and kraal manures in many aspects.Int. J. Agril. Res. Innov. & Tech. 8 (1): 1-6, June, 201

Morpho-physiological and Yield Responses Associated with Plant Density Variation in Soybean (Glycine max L. (Merrill))

Understanding morpho-physiological factors associated with yield decline at high density in soybean (Glycine max L.) can assist in optimizing productivity and seed quality. The objective of this study was to determine effects of different spacing on development and seed quality. The study tested the concept of yield plasticity. Five varieties that included determinate (SC Safari, Dina and Magoye) and indeterminate (Kaleya and Pan 1867) and three densities (300,000, 400,000 and 550,000 plants/ha) were used. A randomized complete block design arranged in 2 factor- factorial with variety and plant density and 4 replications was used. The experiment was done at Seed Control and Certification Institute in Chilanga, Zambia in 2015. Parameters assessed included: height, branches/plant, chlorophyll, nitrogen, 50 % flowering, pod-fill time, maturity duration, biomass, seed quality, yield and yield components. Significant effects for variety were present for all parameters while plant density effects were highly significant for number of branches/plant, biomass yield, pods/plant, seeds/pod and yield. Interaction effects were observed for pods/plant and seeds/plant. Traits positively and significantly correlated to yield were height, canopy biomass yield, pods/plant and seeds/plant. Biomass, pods/plant, seeds/plant and 100 seed weight contributed significantly to total variation of grain yield. Plant height, biomass yield, number of pods/plant, number of seeds/plant and hundred seed weight were critical parameters determining yield elasticity. Kaleya, Pan 1867 and Dina appeared more tolerant of planting at high density

Shelf life responses of ‘Akito’ rose (Rosa spp.) cut flowers treated with growth regulator benzyl amino purine and microbiocide aluminium sulphate

Rose (Rosa spp.) production for cut flowers is an integral part of the horticultural industry. However, because roses are exotic plants they exhibit serious problems related to poor climatic adaptation. A study was conducted at the School of Agricultural Sciences, University of Zambia to evaluate chemicals to extend flower shelf life. The cultivar ‘Akito’ was used as the test variety. Benzyl amino purine ([6- (benzylamino) purine]) (BAP), a growth regulator and aluminium sulphate (an acidifying reagent) were applied to cut flowers at 0, 5, 10, 15, and 20 mg L-l and 0, 400, 800 and 1200 mg L-l, concentration, respectively. BAP was applied to the plants in the greenhouse 2 days before harvest. A randomised complete block design arranged as a two- factor- factorial arrangement with three replications was used. Harvesting was done at the loose open calyx stage. Aluminium sulphate was applied to the holding solution where flowers were kept after harvest. The pH of the holding solution, blossoming (flower opening), leaf color of subtending leaves and bacterial population were monitored. The 400 mg L-l aluminium sulphate treatment caused an increase in acidity. There was concurrent decline in bacterial count in the first three days of application at less than 1 x 106 which was five times lower than the water control treatment. Bacterial population followed the trend of water acidity. The 20 mg L-l BAP application increased shelf life by 35 %. The results showed that BAP and aluminum sulphate treatment could enhance shelf life. Int. J. Agril. Res. Innov. Tech. 10(1): 6-12, June 202

Effect of apical dominance on bud take in Citrus vegetative propagation

The objective of the study was to identify the grafting method, which will have a higher success rate of scion development. The study was conducted at Mount Makulu Central Research station in Chilanga, Zambia (15o33S / 28o11E) from April 2010 to November 2011. The study had 4 vegetative propagation methods that varied in the treatment of the rootstock and scion. The four methods were Standard T- budding (STB); Modified TBudding with decapitation (TBD); T- budding with scion bending (TBB); Crown grafting (CG). Bud take, shoot growth, leaf emergence and Leaf area index were measured up to 11 weeks after treatment (WAT). With CG there was 100 % bud take. STB had a bud take of 58.3 %. TBD had a bud take of 50 %. The lowest bud take percentage was recorded in TBB, which had a bud take of 41.7 %. At 5 weeks the STB and TBB treatment had shoot length of 0.7 and 1.0 cm respectively which were the shortest; this was followed by the CG treatment at 15.3 cm and the modified TBD with apical shoot decapitation (21.7 cm). STB shoots did not start growing until about 5 weeks, which was 2 weeks after the rootstock was cut off. At 5 weeks, the TBB and STB were yet to form leaves. The CG had close to 20 leaves and the TBD had almost 15.2 leaves. At the end of 11 weeks, the TBB had the highest number of leaves. Across the grafting methods; the Leaf area exhibited a pattern similar to leaf number; it kept on doubling every 2 weeks to until the 9th week after which the increase was negligible. At 11 weeks, the highest leaf area was in the TBD followed by the STB and lowest in the CG treatment.Int. J. Agril. Res. Innov. & Tech. 7 (1): 64-70, June, 201

Cassava mosaic disease: incidence and yield performance of cassava cultivars in Zambia

Article purchasedCassava is the main food crop for an estimated 30% of the population in Zambia where yields of 5.8 t/ha are some of the lowest of any major cassava-producing country. A study was conducted to characterize yield responses of Zambian cassava genotypes to cassava mosaic disease (CMD), as well as the relative susceptibilities to the causal viruses. CMD-free planting material of four improved cultivars (Mweru, Chila, Tanganyika and Kampolombo), four officially-promoted landraces (Nalumino, Kapumba, Bangweulu and Katobamphunta) and a locally popular landrace (Manyopola) were evaluated at a field site in Rufunsa District, Lusaka Province (central-eastern Zambia). Manyopola and Bangweulu were found to be susceptible and had high foliar incidences of CMD (97.5% and 74.7%, respectively) based on visual CMD symptoms with high severity scores (3.5, 3.5), whilst cv. Kampolombo was resistant (incidence 0.7%, severity 2.0). Mweru had the highest root yield (17.6 t ha-1 ) while Kapumba, the second most susceptible cultivar, had the lowest root yield (3.2 t ha-1 ). Significant inverse regression 2 relationships were demonstrated between CMD incidence and CMD severity with root yield. Using these regressions together with published data on cassava production and countrywide CMD incidence in Zambia, it was possible to estimate annual losses due to CMD at ca. US$ 51.7 million. Evidence for resistance to CMD amongst several of the improved cassava cultivars tested suggests that there is great potential for the effective control and management of CMD in Zambia, if these materials could be widely disseminated

Characterization of foot-and-mouth disease viruses in Zambia-implications for the epidemiology of the disease in southern Africa

The livestock industry supports livelihood and nutritional security of at least 42% of people in the Southern African Development Community region. However, presence of animal diseases such as foot-and-mouth disease poses a major threat to the development of this industry. Samples collected from FMD outbreaks in Zambia during 2015–2020, comprising epithelial tissues samples (n = 47) and sera (n = 120), were analysed. FMD virus was serotyped in 26 samples, while 92 sera samples tested positive on NSP-ELISA. Phylogenetic analysis revealed notable changes in the epidemiology of FMD in Zambia, which included: (i) introduction of a novel FMDV SAT-3 (topotype II) causing FMD cases in cattle in Western Province; (ii) emergence of FMDV serotype O (topotype O/EA-2) in Central, Southern, Copperbelt, Western, Lusaka Provinces; and (iii) new outbreaks due to SAT -2 (topotypes I) in Eastern Zambia. Together, these data describe eight different epizootics that occurred in Zambia, four of which were outside the known FMD high-risk areas. This study highlights the complex epidemiology of FMD in Zambia, where the country represents an interface between East Africa (Pool 4) and Southern Africa (Pool 6). These changing viral dynamics have direct impacts on FMD vaccine selection in the SADC region.The Government of Zambia through the Ministry of Fisheries and Livestock, Department of Veterinary; the UK Department of the Environment, Food and Rural Affairs (Defra SE2944) and the European Union.http://www.mdpi.com/journal/virusespm2022Veterinary Tropical Disease

Seasonal Dynamics of Mobile Carbon Supply in Quercus aquifolioides at the Upper Elevational Limit

Many studies have tried to explain the physiological mechanisms of the alpine treeline phenomenon, but the debate on the alpine treeline formation remains controversial due to opposite results from different studies. The present study explored the carbon-physiology of an alpine shrub species (Quercus aquifolioides) grown at its upper elevational limit compared to lower elevations, to test whether the elevational limit of alpine shrubs (<3 m in height) are determined by carbon limitation or growth limitation. We studied the seasonal variations in non-structural carbohydrate (NSC) and its pool size in Q. aquifolioides grown at 3000 m, 3500 m, and at its elevational limit of 3950 m above sea level (a.s.l.) on Zheduo Mt., SW China. The tissue NSC concentrations along the elevational gradient varied significantly with season, reflecting the season-dependent carbon balance. The NSC levels in tissues were lowest at the beginning of the growing season, indicating that plants used the winter reserve storage for re-growth in the early spring. During the growing season, plants grown at the elevational limit did not show lower NSC concentrations compared to plants at lower elevations, but during the winter season, storage tissues, especially roots, had significantly lower NSC concentrations in plants at the elevational limit compared to lower elevations. The present results suggest the significance of winter reserve in storage tissues, which may determine the winter survival and early-spring re-growth of Q. aquifolioides shrubs at high elevation, leading to the formation of the uppermost distribution limit. This result is consistent with a recent hypothesis for the alpine treeline formation

Shading effects of intercropping roselle (Hibiscus sabdariffa) genotypes on plant development, assimilate partitioning and leaf nutrient content

An experiment was conducted to determine the effects of shade on plant development, macronutrient and secondary metabolites in roselle (Hibiscus sabdariffa). Three roselle accessions (ZM 5729, ZM 5738 and ZM ZM5748) acquired from the Zambia National Plant Genetic Resource Centre were used and shade was imposed by intercropping roselle with maize (Zea mays). A Split plot design with shade as main plot and genotype as split- plot was used. Nutritional and development parameters were monitored. At 14 weeks shaded plants had about a three-fold decrease in branches numbers compared to unshaded ones. Plant height was higher in unshaded treatments (120 cm) compared to shaded (83 cm). Plant height of ZM 5738 was significantly higher than the other two accessions. Shading reduced dry matter accumulation by almost 75 % across genotypes with about 20 g per plant in shaded treatments and 73 g in unshaded treatments. Nutrient reductions were highest in fat (60.6 %), fibre (48.4 %), protein (37.8 %), and lowest in ash (27.3 %). In terms of strength of partitioning the pattern was: branches ˃ leaves ˃ roots ˃ squares ˃ flowers. The carbohydrate content increased with shading (10.6 %). Vitamin C content was higher in unshaded treatments in comparison with shaded conditions. ZM 5738 had the highest content followed by ZM 5748 and ZM 5729 had the least content. Oxalates which are an anti- nutrition factor increased with shade. The findings showed that there is significant variation among genotypes and in future selections can be made to choose the most productive genotypes