Overview of Biological Methods of Weed Control

Exotic plants in new ecosystems where they may be of no economic importance and where their original biological enemies may be absent become weeds, difficult to manage by crop farmers. They limit the productivity of the lands and hence affect crop development and yield. Efforts towards reducing reliance on herbicides and other methods for environmental, health, economic and sustainability reasons have led to increasing interest in the biological approach to controlling these weeds. This work therefore presents an overview of the biological approach to weed control with focus on the basic concepts, underlying principles, procedures and current practices, cases and causes of failure and successes. Specifically, this chapter has discussed the underlying principles, general procedures, reasons for relatively slow popularity and adoption of biological weed control, examples of successful biological control of weeds with introduced insects and pathogens, when is weed biological control successful?, things to consider when making the choice of agents to be introduced to control weeds and steps to identifying and introducing biological control agents

Evaluation of different packaging types for adoption in safe handling and transportation of fresh tomato fruits in Nigeria

ABSTRACTThis work evaluated plastic, wooden and carton crates and compared the best of them to traditional basket for possible adoption in safe handling and transportation of fresh tomato fruits in Nigeria. This was achieved through laboratory experiments and analysis involving static tests, simulating storage conditions (at average temperature and humidity of 28.920C and 62.08% respectively) and dynamic tests, simulating handling and transportation conditions involving dropping from different heights and vibration at different amplitudes and frequency. Based on experimental results and economic considerations, carton crate was adjudged the best and a new modified design of it was developed. The performance of the designed crate and the traditional basket presently in use in Nigeria was compared. Results of comparative predictive analysis between the carton and the traditional basket revealed that losses that can be incurred using traditional basket while on transit is about 6.25-7.08%; which can be reduced to an average of 5.71% when carton crates are used. In case of accident, the traditional method can incur an average loss of 51.59%, which can be reduced to an average of 37.88% when carton crates are used. In case of delay in travel (2-3weeks), the traditional method may lose an average of 23.81-88.10%, but this can be reduced to 14-67% when carton crates are used

Molecular Genetic Diversity in Bambara groundnut [Vigna subterranea (L.) Verdc] Assessed by Microsatellite Markers

Bambara groundnut is a valuable leguminous crop with many landraces. A study was carried out to establish genetic diversity and phylogenetic relationship, among 33 Bambara groundnut accessions based on simple sequence repeat (SSR) markers. The nine microsatellite markers amplified a total of 27 alleles with a mean of 6.00 alleles per locus. Marker P 36 had the highest number of polymorphic bands while makers P131 and P68 were monomorphic. Genetic distance among the accessions based on Jaccard’s similarity coefficient ranged from 0.84 to 1.00. Cluster analysis resolved the accessions into five major groups with subgroups. Each group had a combination of distinct accessions from different geographical origin. A substantial level of intra-accession polymorphism was obtained among the evaluated collection of Bambara groundnut. The significant genetic diversity observed can support the selection of appropriate parental genotypes for the improvement of Bambara groundnut through various breeding programmes

Effect of organic photovoltaic and red-foil transmittance on yield, growth and photosynthesis of two spinach genoty

The galloping rise in global population in recent years and the accompanying increase in food and energy demands has created land use crisis between food and energy production, and eventual loss of agricultural lands to the more lucrative photovoltaics (PV) energy production. This experiment was carried out to investigate the effect of organic photovoltaics (OPV) and red-foil (RF) transmittance on growth, yield, photosynthesis and SPAD value of spinach under greenhouse and field conditions. Three OPV levels (P0: control; P1: transmittance peak of 0.11 in blue light (BL) and 0.64 in red light (RL); P2: transmittance peak of 0.09 in BL and 0.11 in RL) and two spinach genotypes (bufflehead, eland) were combined in a 3 × 2 factorial arrangement in a completely randomized design with 4 replications in the greenhouse, while two RF levels (RF0: control; RF1: transmittance peak of 0.01 in BL and 0.89 in RL) and two spinach genotypes were combined in a 2 × 2 factorial in randomized complete block design with four replications in the field. Data were collected on growth, yield, photosynthesis and chlorophyll content. Analysis of variance (ANOVA) showed significant reduction in shoot weight and total biomass of spinach grown under very low light intensities as a function of the transmittance properties of the OPV cell used (P2). P1 competed comparably (p > 0.05) with control in most growth and yield traits measured. In addition, shoot to root distribution was higher in P1 than control. RF reduced shoot and total biomass production of spinach in the field due to its inability to transmit other spectra of light. OPV-RF transmittance did not affect plant height (PH), leaf number (LN), and SPAD value but leaf area (LA) was highest in P2. Photochemical energy conversion was higher in P1, P2 and RF1 in contrast to control due to lower levels of non-photochemical energy losses through the Y(NO) and Y(NPQ) pathways. Photo-irradiance curves showed that plants grown under reduced light (P2) did not efficiently manage excess light when exposed to high light intensities. Bufflehead genotype showed superior growth and yield traits than eland across OPV and RF levels. It is therefore recommended that OPV cells with transmittance properties greater than or equal to 11% in BL and 64% in RL be used in APV systems for improved photochemical and land use efficiency