Genomics,genetics and breeding of tropical legumes for better livelihoods of smallholder farmers

Legumes are important components of sustainable agricultural production, food, nutrition and income systems of developing countries. In spite of their importance, legume crop production is challenged by a number of biotic (diseases and pests) and abiotic stresses (heat, frost, drought and salinity), edaphic factors (associated with soil nutrient deficits) and policy issues (where less emphasis is put on legumes compared to priority starchy staples). Significant research and development work have been done in the past decade on important grain legumes through collaborative bilateral and multilateral projects as well as the CGIAR Research Program on Grain Legumes (CRP‐GL). Through these initiatives, genomic resources and genomic tools such as draft genome sequence, resequencing data, large‐scale genomewide markers, dense genetic maps, quantitative trait loci (QTLs) and diagnostic markers have been developed for further use in multiple genetic and breeding applications. Also, these mega‐initiatives facilitated release of a number of new varieties and also dissemination of on‐the‐shelf varieties to the farmers. More efforts are needed to enhance genetic gains by reducing the time required in cultivar development through integration of genomics‐assisted breeding approaches and rapid generation advancement.     

Comparison of quality of induction of anaesthesia between intramuscularly administered ketamine, intravenously administered ketamine and intravenously administered propofol in xylazine premedicated cats

The quality of induction of general anesthesia produced by ketamine and propofol, 2 of the most commonly used anaesthetic agents in cats, was assessed. Eighteen cats admitted for elective procedures were randomly assigned to 3 groups and then premedicated with xylazine 0.75 mg/kg intramuscularly before anaesthesia was induced with ketamine 15 mg/kg intramuscularly (KetIM group), ketamine 10 mg/kg intravenously (KetIV group) or propofol 4 mg/kg intravenously (PropIV group). Quality of induction of general anaesthesia was determined by scoring ease of intubation, degree of struggling, and vocalisation during the induction period. The quality of induction of anaesthesia of intramuscularly administered ketamine was inferior to that of intravenously administered ketamine, while intravenously administered propofol showed little difference in quality of induction from ketamine administered by both the intramuscular and intravenous routes. There were no significant differences between groups in the ease of intubation scores, while vocalisation and struggling were more common in cats that received ketamine intramuscularly than in those that received intravenously administered ketamine or propofol for induction of anaesthesia. Laryngospasms occurred in 2 cats that received propofol. The heart rates and respiratory rates decreased after xylazine premedication and either remained the same or decreased further after induction for all 3 groups, but remained within normal acceptable limits. This study indicates that the 3 regimens are associated with acceptable induction characteristics, but administration of ketamine intravenously is superior to its administration intramuscularly and laryngeal desensitisation is recommended to avoid laryngospasms.     

Preparation of Chito-Oligomers by Hydrolysis of Chitosan in the Presence of Zeolite as Adsorbent

An increasing interest has recently been shown to use chitin/chitosan oligomers (chito-oligomers) in medicine and food fields because they are not only water-soluble, nontoxic, and biocompatible materials, but they also exhibit numerous biological properties, including antibacterial, antifungal, and antitumor activities, as well as immuno-enhancing effects on animals. Conventional depolymerization methods of chitosan to chito-oligomers are either chemical by acid-hydrolysis under harsh conditions or by enzymatic degradation. In this work, hydrolysis of chitosan to chito-oligomers has been achieved by applying adsorption-separation technique using diluted HCl in the presence of different types of zeolite as adsorbents. The chito-oligomers were retrieved from adsorbents and characterized by differential scanning calorimetry (DSC), liquid chromatography/mass spectroscopy (LC/MS), and ninhydrin test.     

Diallel analysis of grain yield and resistance to seven diseases of 12 African maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) inbred lines

Maize (Zea mays L.) is grown on 15 million ha in eastern and southern Africa. Several diseases are of common occurrence in the region and regularly result in significant yield losses. A collaborative regional disease nursery (REGNUR) project was initiated in 1998 to identify and increase access to disease resistant germplasm, generate and disseminate information on disease and insect resistance sources, and facilitate the development of resistant cultivars by project partners. A diallel among 12 elite inbred lines was formed with the specific objective of evaluating the combining ability of these inbred lines for grain yield and resistance to seven diseases. The trial was grown at six sites in 2001. Results showed that both general (GCA) and specific combining ability effects were significant for most diseases. On the average, GCA accounted for 69% of resistance to diseases and only 37% of variation for grain yield. Correlations between GCA effects for disease scores were generally non-significant, implying that it is possible to pyramid genes for disease resistance in inbred lines. This underscores the need for screening for resistance to prevailing diseases using artificial inoculation or reliable hot-spots. Based on GCA effects for grain yield and across diseases, P12 and P6 were the best inbred lines. The crosses P4 × P9 (6.7 t ha⁻¹) and P4 × P12 (6.9 t ha⁻¹) were the best hybrids in the earlier maturity group, while P3 × P9 (8.3 t ha⁻¹) and P2 × P8 (7.4 t ha⁻¹) were the best hybrids in the late maturity group.     

Co-Processed Chitin-Mannitol as a New Excipient for Oro-Dispersible Tablets

This study describes the preparation, characterization and performance of a novel excipient for use in oro-dispersible tablets (ODT). The excipient (Cop–CM) consists of chitin and mannitol. The excipient with optimal physicochemical properties was obtained at a chitin: mannitol ratio of 2:8 (w/w) and produced by roll compaction (RC). Differential scanning calorimetry (DSC), Fourier transform-Infrared (FT-IR), X-ray powder diffraction (XRPD) and scanning electron microscope (SEM) techniques were used to characterize Cop–CM, in addition to characterization of its powder and ODT dosage form. The effect of particle size distribution of Cop–CM was investigated and found to have no significant influence on the overall tablet physical properties. The compressibility parameter (a) for Cop–CM was calculated from a Kawakita plot and found to be higher (0.661) than that of mannitol (0.576) due to the presence of the highly compressible chitin (0.818). Montelukast sodium and domperidone ODTs produced, using Cop–CM, displayed excellent physicochemical properties. The exceptional binding, fast wetting and superdisintegration properties of Cop–CM, in comparison with commercially available co-processed ODT excipients, results in a unique multifunctional base which can successfully be used in the formulation of oro-dispersible and fast immediate release tablets.     

Activities of Carbon and Nitrogen Metabolism Enzymes of Sorghum (<Emphasis Type="Italic">Sorghum bicolor</Emphasis> L. Moench) During Seed Development

Carbon and nitrogen metabolism pathways are regulated by complex mechanisms in order to optimize growth and development of plants and play a major role in determining the amount of protein stored in cereal grains. This study was conducted to contribute to determine the roles of certain key enzymes of carbon and nitrogen metabolism in developing sorghum seeds. Sorghum bicolor (L.) Moench was grown in a growth chamber. Seeds were harvested at various stages of development and used to the analysis of certain key enzymes of carbon and nitrogen metabolism. The results were subjected to stastistical analysis using one-way analysis of variance (ANOVA) followed by the Tukey test. The results showed that during the seed development the highest activities of glutamine synthetase, glutamate dehydrogenase, phosphoenolpyruvate carboxylase, malate dehydrogenase, isocitrate dehydrogenase, and aspartate aminotransferase were detected at the time of maximum seed filling stages (15-20 DAP). Hence, higher activities of these enzymes at the time of maximum seed-filling stages could be effectively linked to amino acids synthesis and therefore the deposition of protein reserves.     

Toxicity of neem (Azadirachta Indica) seed kernel extracts prepared with different solvents,on the spider chiracanthium mildei

The toxicity of neem seed kernel extracts prepared with different solvents against the predatory spider,Chiracanthium mildei L. Koch, was investigated. The order of toxicity of the 4% extracts was pentane < acetone < ethanol << methanol = water (nontoxic). All extracts were nontoxic at 2.5%.     

Market‐led options to scale up legume seeds in developing countries: Experiences from the Tropical Legumes Project

There are several hurdles to ensure sustainable seed production and consistent flow of improved legume varieties in sub‐Saharan Africa (SSA) and South Asia (SA). The unreliable demand, autogamous nature of most of the grain legumes, and slow variety replacement rate by smallholder farmers do not provide strong incentive for private seed companies to invest in legume seed business. Unless a well thought‐out and comprehensive approach to legume seed delivery is developed, current seed shortages will continue, eroding emerging market opportunities. The experiences reported here are collated through a 10‐year partnership project, the Tropical Legumes in SSA and SA. It fostered innovative public–private partnerships in joint testing of innovative market‐led seed systems, skills and knowledge enhancement, de‐risking private sector initiatives that introduced in new approaches and previously overlooked entities in technology delivery. As new public and private seed companies, individual seed entrepreneurs and farmer organizations emerged, the existing ones enhanced their capacities. This resulted in significant rise in production, availability and accessibility of various seed grades of newly improved and farmer demanded legume varieties in the target countries.     

Genetics,genomics and breeding of groundnut (Arachis hypogaea L.)

Groundnut is an important food and oil crop in the semiarid tropics, contributing to household food consumption and cash income. In Asia and Africa, yields are low attributed to various production constraints. This review paper highlights advances in genetics, genomics and breeding to improve the productivity of groundnut. Genetic studies concerning inheritance, genetic variability and heritability, combining ability and trait correlations have provided a better understanding of the crop's genetics to develop appropriate breeding strategies for target traits. Several improved lines and sources of variability have been identified or developed for various economically important traits through conventional breeding. Significant advances have also been made in groundnut genomics including genome sequencing, marker development and genetic and trait mapping. These advances have led to a better understanding of the groundnut genome, discovery of genes/variants for traits of interest and integration of marker‐assisted breeding for selected traits. The integration of genomic tools into the breeding process accompanied with increased precision of yield trialing and phenotyping will increase the efficiency and enhance the genetic gain for release of improved groundnut varieties.     

effects of neem(Azadirachta indica) seed kernel extracts from different solvents on the predacious mitePhytoseiulus persimilis and the phytophagous miteTetranychus cinnabarinus

The effects of neem seed kernel extracts from different solvents on the predacious mitePhytoseiulus persimilis Athias-Henriot and the phytophagous miteTetranychus cinnabarinus (Boisd.) were compared. All extracts were much more toxic to the latter pest than to the former. Using the respective LC₅₀ for the two species, the toxicity index (LC₅₀ Phytoseiulus/LC₅₀ Tetranychus) was found to be 3 for the methanol, 4 for the ethanol, 23 for the acetone, and 58 for the pentane extract. The order of toxicity of the extracts (pentane > acetone > ethanol > methanol) was valid only forT. cinnabarinus. The EC₅₀s for reduction of fecundity were rather close for the two species.