Influence of eco-friendly control strategies on the germination of mycotoxin secreted Fusarium verticillioides infested maize

Fusarium verticillioides is a major seed borne fungal pathogen of maize causing rots and seedling blight, and secretion of toxigenic compounds in grains. This study aimed at reducing the seedling blight and mycotoxin contamination level of maize caused by F. verticillioides with environmentally friendly antagonistic microorganisms. One gram of ground mycelia of each of the species of Trichoderma, B. subtilis and P. fluorescens was suspended in 100, 200, 300 and 400ml of distilled water to determine the inoculum concentrations. Maize seeds were treated with inoculum and planted at least 2 seeds per pot in replicates of 3 pots. Two grams of ground mycelial mat of the pathogen was added (at planting) per ten (10) kilogram of sterile soil. Germination percentage of these seeds was taken on the 14, 21, and 28 days after planting. Observations were on incidence and severity of the disease, from germination period till harvest. T. pseudokoningii at its C3 gave the best germination percentage, and P. fluorescens inoculum at C2 was the best for the control of the pathogen, which is comparatively effective as Benomyl against F. verticillioides. The use of ecofriendly control alternative like T. pseudokoningii and P. fluorescens should be used to in place Benomyl; it has no residual effect on the environment.Keywords: maize, mycotoxin, biocontrol agents, Fusarium sp

Evaluation of genetic diversity in some Amaranthus spp. using morphological and Random Amplified Polymorphic DNA(RAPD) analysis

Amaranth, is an annual plant used as leafy vegetables, grains and ornamentals. It is a plant with a wide range of variability. Ten Amaranth genotypes were selected based on their morphological features and were evaluated over two seasons in 2016 at the Teaching and Research Farms, Federal University of Agriculture, Abeokuta, (FUNAAB), while the molecular analyses were carried out at the Laboratory of the Biotechnology Centre, FUNAAB. DNA extracted from young amaranth leaves were amplified using four Random Amplified Polymorphic DNA (RAPD) primers (OPA-02, OPA-10, OPB-11 and OPB-12). Data collected were subjected to statistical analyses. The Analysis of Variance revealed significant variation in the accessions with respect to height at flowering and number of branches only. Heritability estimates ranged from 60 – 94% for petiole length and number of branches, respectively. A significant and negative correlation was observed between number of branches and seed weight (-0.35**). Molecular cluster analysis showed that all the accessions studied shared a similarity at a coefficient of 0.55 and two major clusters were formed at a coefficient of 0.60. For hybridization studies, accessions NGB-96 and NGB/09/09 which were from distant cluster could be used as parents to take advantage of the inherent variability. Other markers such as Simple Sequence Repeats (SSR) could be used to further reveal diversity in the accessions

Genetic diversity in Amaranth (Amaranthus spp.) based on phenotypic and RAPD markers

Genetic similarities, which can be detected with phenotypic and molecular markers, are important for effective use of available germplasm. It provides information on genetic diversity for reliable gene recombination. Thirty accessions of amaranth were assessed for variation with 15 phenotypic characters and 10 random amplified polymorphic DNA (RAPD) primers. Significant (p < 0.05) phenotypic variation was observed among the accession at the vegetative phase and most of the accessions had leaves with green pigmentation. Sink factor such as leaf, stem and root weights, and dry matter, were homogenous traits which contributed significantly to diversity among the accessions. The RAPD primers produced 115 bands with 88 (77%) polymorphic loci. The DNA classification between some of the accessions was similar to the phenotypic diversity. Information on phenotypic diversity and traits contributing to the diversity can be used deductively with genetic diversity to guide effective hybrid program.Keywords: Accession, genetic divergence, Mahanalobis, oligonucleotide, polymorphism, UPGM

Genetic diversity in some Nigerian kenaf (Hibiscus cannabinus L.) genotypes as assessed by agro-morphological traits and seed protein markers

Identifying and assessing genetic diversity in kenaf (Hibiscus cannabinus L.) using agromorphological markers is problematic, thus, necessitating the use of biochemical markers. Thirty five kenaf genotypes were evaluated for genetic diversity using 13 agromorphological characters and seed proteins. The field experiment was laid out in a Randomized Complete Block Design with three replications; the data were subjected to Principal Component Analysis (PCA) and Cluster Analysis (CA) to group the genotypes. The observed genetic diversity among the genotypes based on Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of seed proteins was presented in the form of a dendrogram generated by the UPGMA cluster analysis. The relative effectiveness of the two types of markers in assessing the diversity among the genotypes was investigated. The CA grouped the 35 genotypes into eight clusters; the PCA revealed that the first three principal components accounted for 66.60% of the total variation among the genotypes. Plant height, stalk height, internode distance, number of seeds/pod, basal stem diameter, number of pods/plant, pod length and seed yield/plant were identified as traits that best described the genotypes. The seed protein dendrogram, in addition to grouping the 35 genotypes into four major clusters, was able to identify duplicates within the population.Keywords: Biochemical markers, principal components analysis, dendrogram, duplicate

RELATIVE DISCRIMINATING POWERS OF GGE AND AMMI MODELS IN THE SELECTION OF TROPICAL SOYBEAN GENOTYPES

Selection of crops is preceded by multi-locational testing in plant breeding; however, it becomes difficult for breeders to determine which genotypes should be selected in the presence of genotype by environment (GEI). Six genotypes of soybean ( Glycine max (L.) Merr.) were evaluated at ten locations in Nigeria for grain yield and stability. The analysis of variance revealed significant (P 640.05) GEI effect. Mean grain yield of the soybean genotypes ranged from 1148 kg ha-1 for genotype M351 to 1584 kg ha-1 for TGx 1448-2E. Ilorin in the southern guinea savanna of Nigeria was the most variable with high interaction principal component axes (IPCA); while Bauch in the northern guinea savanna was identified as more stable location in evaluating the soybean genotype. Mega-environments and the best yielding soybean genotypes in each mega-environment were revealed by the GGE biplot analysis. Furthermore, TGx 1448-2E and TGx 1440-1E, were established as the most promising, and stable genotypes across the test locations. Stability model of GGE biplot was superior, effective and informative in mega-environment analysis compared to AMMI analysis.La s\ue9lection des cultures est pr\ue9c\ue9d\ue9e de tests multilocaux en am\ue9lioration des plantes; cependant, il appara\ueet difficile pour les am\ue9liorateurs de d\ue9terminer quels types de g\ue9notypes s\ue9lectionner en pr\ue9sence du g\ue9notype x environnement (GEI). Six g\ue9notypes du Soja ( Glycine max (L.) Merr.) \ue9taient \ue9valu\ue9s dans dix milieux au Nigeria pour le rendement en grains et la stabilit\ue9. L\u2019analyse de la variance a r\ue9v\ue9l\ue9 un effet significatif (P 64 0.05) du GEI. Le rendement moyen en grains des g\ue9notypes du soja variait de 1148 kg ha-1 pour le g\ue9notype M351 \ue0 1584 kg ha-1 pour TGx 1448-2E. Ilorin au sud de la savanne guin\ue9enne au Nigeria \ue9tait le plus variable avec une interaction \ue9lev\ue9e des axes de la composante principale (IPCA); pendant que Bauch dans le nord de la savanne guinn\ue9enne \ue9tait identifi\ue9 comme milieu le plus stable dans l\u2019\ue9valuation du g\ue9notype du soja. Les Mega-environments et le meilleur g\ue9notype du soja du point de vue rendement dans chaque mega-environment \ue9taient r\ue9v\ue9l\ue9s par l\u2019analyse du biplot. En plus, TGx 1448-2E et TGx 1440-1E, \ue9taient jug\ue9s les plus promettants et g\ue9notypes stables \ue0 travers le test de milieu. Le mod\ue8le de stabilit\ue9 du biplot GGE \ue9tait sup\ue9rieur, effective et informative dans l\u2019analyse m\ue9ga-environmentale en comparaison avec l\u2019analyse du AMMI

Effect of iodine biofortification on incidence and severity of Fusarium wilt and yield of tomato (Solanum lycopersicum L.)

Tomato is often attacked by wilt caused by Fusarium oxysporium. Iodine is known to have fungistatic effect in pathogen control. The present experiment was aimed at determining the effect of iodine compounds (potassium iodide, KI and potassium iodate, KIO3) on incidence and severity of Fusarium wilt and yield of two tomato accessions, FUNAABTO/106 and FUNAABTO/123. The experiment was conducted in the screenhouse and on the field. KI was applied at concentrations of 1, 2, 3, 5 mM while KIO3 was applied at concentrations of 0.5, 1, 2, 3 mM. The untreated plots served as control. Results showed that FUNAABTO/106 treated with 0.5 mM KIO3 in the screenhouse and on the field had the least (0.00%) disease incidence. Disease severity was significantly (p ≤ 0.05) lower (1.00) in the screenhouse in pots containing FUNAABTO/106 treated with 1 mM KIO3. On the field, FUNAABTO/106 treated with 0.5 mM KIO3 had the least (1.17) disease severity. FUNAABTO/106 treated with 0.5 mM KIO3 in the screenhouse and on the field were significantly higher (1.65t/ha and 18.54t/ha respectively) in yield. The study concluded that application of iodine compounds at lower concentrations reduced the incidence and severity of Fusarium wilt and increased the yield of tomato.Keywords: Potassium iodate (KIO3), Potassium iodide (KI), Fusarium oxysporiu

Genetic variability and associations between grain yield and related traits in Amaranthus cruentus and Amaranthus hypochondriacus grown at two locations

For plant genetic improvement, it is paramount to determine genetic components for the selection of desirable traits. Eighteen Amaranthus cruentus and 11 Amaranthus hypochondriacus genotypes were evaluated at two locations in Nigeria differing in temperature/precipitation to determine the influence of environment on genetic gain. Genotype × environment was significant for all analysed morphological parameters and for grain yield, 1000 seed weight and no. of days to 50% flowering in A. cruentus. In A. hypochondriacus genotype × environment was significant for plant height, leaf length and width, leaf area, inflorescence length, 1000 seed weight and grain yield. Higher genotypic coefficient of variability, heritability estimates, and genetic advance was observed for the traits at Abeokuta (more wet) than Ibadan (more dry) conditions. Grain yield had positive association with the traits at the two locations except the number of leaves and inflorescence length. Inflorescence length was positively associated with grain yield at Abeokuta and negatively associated at Ibadan. Path analysis indicated simultaneous improvement of grain yield with petiole length and leaf length at Abeokuta but with petiole length and leaf area at Ibadan. In general, the locations had potential for genetic improvement of traits of amaranth grain; therefore, selection criteria for improving grain yield should be considered with respect to environment

Heterosis and combining ability study in African eggplant (Solanum aethiopicum L.)

The choice of breeding method for genetic improvement of a crop depends on the nature of gene action involved in the expression of its quantitative traits. Hybrid vigour has become a potential tool for genetic improvement of many crops. This study examined heterosis and gene action controlling yield and component traits for selection among eggplant accessions. Four accessions of Solanum aethiopicum (ACN.NH-165; ACN.NH-124; ACN.NH-159 and ACN.NH-125) were crossed using diallel mating designed to produce first filial generation without reciprocals. The four parents and six diallel-crosses generated were evaluated between July-December, 2014, at National Horticultural Research Institute Ibadan, using randomized complete block design with three replications. Data collected on days to 50% flowering, plant height (cm), number of leaves per plant, fruit length (cm), fruit diameter (cm), number of fruits per plant, fruit weight per plant (g) and 1000-seed weight (g) were analyzed for general combining ability (GCA), specific combining ability (SCA) and heterosis estimation. Significant genetic variation was observed among the lines used with respect to all traits evaluated. GCA mean square was significant for all the traits studied, while SCA mean square was not significant for plant height and number of fruits per plant. Almost all give specific figure or value the studied traits had >50% proportion of total genotypic sum of square due to GCA except number of leaves. Heterobeltiosis was observed in ACN.NH-165 × ACN.NH-124 for earliness (-1.15%), 1000-seed weight (21.03%), fruit length (28.50%), fruit diameter (26.65%); and ACN.NH-124 × ACN.NH-125 for number of fruits per plant (7.70%). ACN.NH-124, ACH.NH-165 and ACH.NH-125 which were good combiners in the present study can be used as parents in hybridization breeding program for earliness, higher fruit yield and bigger sized of fruits of Solanum aethiopicum

Genetic variability study and path coefficient analysis in African eggplant ( Solanum aethiopicum L.)

Genetically improved African eggplant is needed for the exploitation of its potential for commercial use. Heritability and knowledge of correlation among agronomic traits help plant breeders decide which selection methods will be effective in crop improvement. Ten genotypes were grown at the research farm of NIHORT in July, 2014, using Randomized Complete Block Design in three replications, to determine the extent of genetic variability, strength of association and level of heritability among nine agronomic traits. Estimates of phenotypic and genotypic coefficient of variance, broad sense heritability, genetic advance, phenotypic and genotypic correlation coefficients were computed. Number of leaves per plant had the highest genotypic variance (253.98), while number of leaves per plant had the highest phenotypic variance (281.06). Number of leaves per plant, days to 50% flowering and fruit weight per plant showed high genotypic and phenotypic variance indicating that the genotype could be reflected by the phenotype and selection based on the phenotype performance of these traits could be effective. High heritability and high genetic advance observed in days to 50% flowering, stem girth, number of leaves per plant and fruit weight per plant revealed the preponderance of additive gene action which shows that selection for these characters could be effective. At genotypic level, fruit diameter had the highest direct effect on fruit weight per plant, while at phenotypic level; fruit length had the highest direct effect on fruit weight per plant. These two characters can be used as selection index for fruit weight per plant in eggplant improvement

Seeds and seedlings vigour in tropical maize inbred lines

Seed and seedling vigour is an aspect of seed quality which affects field establishment and performance. Low maize yields have been reported  to be affected by several factors in which poor quality seed with low seed and seedling vigour. Information is scarce on seed and seedling vigour in maize inbred lines developed for tropical environments. Fifteen genotypes of tropical maize (Zea mays L.) inbred lines were evaluated to determine the level of differences in seed and seedling vigour traits, and extent of relationships among traits and their heritability. A substantial amount of genetic variability was found, which suggested that most of the traits under study could be improved through selection and utilized in breeding programs. Positive and signifi- cant interrelationship  among  seed germination  and seedling  traits  and  a positive  correlation  between  seed germination and seed vigour and field emergence showed that these could be given due consideration in crop improvement for seed and seedling vigour. High genotypic coefficient of variation, heritability and genetic advance were obtained for seed germination, seed emergence, shoot length and seedling vigour index I and II, revealing the possibility of improvement in these characters through direct selection. The principal component analysis (PCA) identified seed emergence, shoot length, seedling vigour index I and II and tetrazolium vigour as characters that contributed greatly to variation in seed vigour in the maize inbred lines. Cluster analysis partitioned the genotypes into two groups, with group I consisting of seven genotypes and group II comprised the other eight genotypes, which suggested that hybridization between the two groups could lead to high level of heterosis. Genotype V5  had superior seedling vigour traits compared to other genotypes. Seedling emer- gence, shoot length, seedling vigour index I, seedling vigour index II and tetrazolium vigour are effective characters for good seedling vigour traits in maize inbred lines investigated