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Application of microsatellite markers for hybrid verification and genetic analysis of oil palm (Elaeis guineensis Jacq.)

The legitimacy of parents and progenies used in crop improvement programmes is vital for any meaningful progress in selection. While acknowledging the shortcomings of controlled pollination in oil palm breeding and commercial seed production, the legitimacy of 20 oil palm progenies from the Nigerian Institute for Oil Palm Research (NIFOR) breeding programme was determined using 16 fluorescently-labeled microsatellite markers. The genotyping of parents and progenies was conducted by capillary electrophoresis using the ABI 3730 DNA Genetic Analyzer (Applied Biosystems, USA). Results revealed a complementary expression of the parents’ alleles in 18 out of the 20 individual progenies screened, confirming their hybridity and genetic identity. The two illegitimate progenies detected could be attributed to pollination and planting errors, respectively. A subset of three sufficiently informative loci (sMg00016, sMg00179 and sMo00102) was identified for routine quality control genotyping. The detection of illegitimate progenies provided ample evidence to substantiate the importance of assessing hybrid fidelity in breeding programmes. Furthermore, the usefulness of microsatellite markers as a reliable technique for routine assessment and unambiguous identification of oil palm crosses was established. The implications of microsatellite- based hybrid identification in oil palm varietal improvement programmes have been adequately discussed. Key words: Contamination, Genetic identity, Illegitimacy, NIFOR, Parent-Progeny relationships, seed productio

Evaluation of the nutritional composition ofthe seeds of some selected African yam bean (Sphenostylis stenocarpa Hochst Ex. A. Rich (Harms)) accessions

African yam bean (AYB) is an important but neglected and underutilized crop producing edible seeds and tubers. The poor awareness of the nutritional values of AYB constitutes one of the major problems limiting its utilization. This study was, therefore, carried out to determine the nutritional potentials of five accessions of African yam bean (TSs 125, TSs 116, TSs 86, TSs 69 and TSs 60) by analyzing their proximate composition and micronutrients (Iron (Fe), Zinc (Zn) and Selenium (Se)). The experiment was laid out in completely randomized design (CRD) with three replications. The results obtained showed significant (p < 0.05) variations in the proximate composition of the AYB accession. The crude protein was in the range of 21.84-23.41 %, crude fat 3.40-3.86 %, fibre 6.17- 6.76 %, carbohydrate 52.8-54.48 %, dry matter 90.42 - 90.6 %, ash 4.22 - 4.35 %, and moisture 9.4 - 9.58 %.The Se concentration varied from 312 mg/100 g in TSs 116 to 58 mg/100 g in TSs 60 while Fe ranged between 10.40 mg/100g in TSs 60 and 6.07mg/100gin TSs 86. Zinc varied between 8.83 mg/100g in TSs116 and 6.37 mg/100 g in TSs 69.TSs 116 was best accession in terms of crude protein, dry matter, ash, selenium and zinc, while TSs 60 was best in terms of iron. The study revealed AYB seeds as a food crop rich in protein, carbohydrate, fibre, selenium, iron and zinc. The genotypic variability can be exploited in developing African yam bean varieties with better qualities in terms of nutrient density.Keywords: Neglected, underutilized, nutrient-dense, micronutrient and protei

Heritability Relationships and Variability of Yield and Yield components in Vegetable Cowpea

Six populations from two crosses of vegetable cowpea ( Vigna unguiculata (L.) Walp) were studied for heritable relationships between yield and yield components. Highly significant differences were observed for all traits. Phenotypic coefficient of variation was higher than the corresponding genotypic coefficient of variation, indicating the influence of genotype x environment interaction in the expression of all characters. Broad and narrow sense heritability estimates were determined for pod length (71 and 65%, cross 1; 66 and 52%, cross 2), for number of seeds pod-1 (74 and 52 %, cross 1; 76 and 52% cross 2), and for number of pods plant-1 (64 and 49%, cross 1; 69 and 49 %, cross 2). Although the heritability values for pod length were relatively high, the non-significant genotypic correlation of pod length with grain yield seems to negate its usefulness as a trait for improvement of yield. The moderate to high heritability values of pods plant-1 and seeds pod-1 and their highly significant positive correlation with yield suggested that pods plant-1 and seeds pod-1 are major yield contributing components

Heritability Relationships and Variability of Yield and Yield components in Vegetable Cowpea

Six populations from two crosses of vegetable cowpea ( Vigna unguiculata (L.) Walp) were studied for heritable relationships between yield and yield components. Highly significant differences were observed for all traits. Phenotypic coefficient of variation was higher than the corresponding genotypic coefficient of variation, indicating the influence of genotype x environment interaction in the expression of all characters. Broad and narrow sense heritability estimates were determined for pod length (71 and 65%, cross 1; 66 and 52%, cross 2), for number of seeds pod-1 (74 and 52 %, cross 1; 76 and 52% cross 2), and for number of pods plant-1 (64 and 49%, cross 1; 69 and 49 %, cross 2). Although the heritability values for pod length were relatively high, the non-significant genotypic correlation of pod length with grain yield seems to negate its usefulness as a trait for improvement of yield. The moderate to high heritability values of pods plant-1 and seeds pod-1 and their highly significant positive correlation with yield suggested that pods plant-1 and seeds pod-1 are major yield contributing components

Implications of polyembryony on the growth and yield of fluted pumpkin (Telfairia occidentalis hook. f.)

Two experiments were conducted during the wet seasons of 2004 and 2005 to investigate the performance of polyembryonic lines with respect to growth and yield of fluted pumpkin. The results revealed three morphotypes of polyembryony, namely: twin (bi-embryony), triple (tri-embryony) and quadruple (tetra-embryony). In the first year (2004), the triple and quadruple embryo types had the highest (54.52%) and lowest (2.02%) frequencies of occurrence, respectively. In the second year (2005), the frequencies of the triple and quadruple embryo types were 60.99% and 4.78%, respectively. There was no clear trend across all the embryo types investigated with respect to the characters measured. However, generally, the triple and the single (mono-embryony) lines performed better than the twin and quadruple lines. The impressive performance of the single and triple embryo types over the twin and quadruple embryo types with respect to the weight of pods, in 2004 and 2005 suggests that these embryo types are good candidates multiplication and distribution to farmers using the micropropagation technique.Key words: Polyembryony, growth, yield, fluted pumpkin, Telfairia occidentalis

Pathogenicity of Meloidogyne Incognita Race 1 on Tomato as Influenced by Different Arbuscular Mycorrhizal Fungi and Bioformulated Paecilomyces Lilacinus in a Dysteric Cambisol Soil

A greenhouse experiment was conducted to investigate the single and combined effects of different arbuscular mycorrhizal fungi (AMF) and bioformulated Paecilomyces lilacinus against M. incognita race 1 on tomato. Dysteric Cambisol soil was used. The experiment took place in Calabar, Cross River State, Nigeria. The experiment was laid out as a 3x6 factorial in a completely randomized design (CRD) with three replications. Three applications of the bionematicide were combined with five species of AMF plus an uninoculated control. The results indicated that AMF species differed significantly (p ≤ 0.05) in their efficacy of gall and egg mass inhibition, tomato root colonization rate as well as growth and fresh fruit yield enhancement. Glomus etunicatum and G. deserticola were the most efficient species. Two applications of the bionematicide more significantly (p ≤ 0.05) reduced galling and egg production than a single application. Individual combinations of two AMF (G. etunicatum and G. deserticola) with a double application of the bionematicide, resulted in the greatest gall and egg mass inhibition and consequently the greatest growth and fresh fruit yield enhancement

Evaluation of elite and local African yam bean cultivars for yield and yield-related traits

Published online: 12 Aug 2022The variability in African yam bean (AYB) accessions with respect to yield and other agronomic traits were studied for two cropping seasons (2012 and 2013) in field experiments to evaluate the growth, yield and yield components of 36 AYB accessions. The accessions differed significantly (P ≤ 0.05) in the traits studied. In 2012 Pearson correlation coefficients indicated that seed yield had significant (P ≤ 0.01) and positive relationships with total pod weight per plant (r = 0.80**), number of filled pods (r = 0.90**) and total number of pods per plant (r = 0.73**). Total pod weight per plant recorded significant and positive relationships with total number of pods per plant (r = 0.88**) and number of filled pods (r = 0.90**). In the 2013 cropping season, seed yield had positively significant (P ≤ 0.01) relationships with total pod weight per plant (r = 0.96**), number of pods per plant (r = 0.89**), number of filled pods (0.92**) and shrivelled pods (r = 0.72**). Total pod weight per plant had positively significant (P ≤ 0.01) relationships with number of pods per plant (r = 0.93**), number of filled pods (r = 0.92**) and shrivelled pods (r = 0.78**). Principal component analysis results identified seed yield, total pod weight, number of filled pods, percentage filled pods, number of days to first emergence, number of days to 50% emergence and number of seeds per pod as the most discriminating traits among the accessions. TSs 137, TSs 111, TSs 118, Tseagbaragba, TSs 60 and TSs 93 were the best performing accessions for seed yield. The evident variability in the AYB accessions evaluated should be made use of in developing improved African yam bean varieties

Ploidy and genome segregation in Musa breeding populations assessed by flow cytometry and randomly amplified polymorphic DNA markers

The majority of edible bananas (Musa L.) are triploid (2n = 3x = 33) cultivars known as dessert, plantain, or cooking bananas with predominant AAA, AAB, and ABB genomes, justifying the aim of breeding programs to develop improved hybrids of the different utilization classes in the triploid background. This usually involves crossing 3x landraces to 2x accessions that are donors of resistance genes, selecting 4x and 2x primary hybrids from the 3x-2x progenies, and crossing 4x-2x hybrids to produce secondary 3x hybrids. Ploidy and genome segregation routinely occurs during this process and constitutes a major hindrance for selection because this is not easily detectable at the morphological level. This study was carried out to assess the potential of early screening for discriminating ploidy and genome classes in 4x (AAAB)-2x (AA) breeding populations, based on flow cytometry and genome-specific RAPD analysis. Results indicate that progenies of 4x-2x crosses produced predominantly 3x progenies (94.1%). RAPD analysis identified seven genomic classes, dominated by AAA and AAB configurations segregating 1:1 (χ2 = 0.21, P = 0.05). Plant size and bunch weight increased with ploidy level, justifying ploidy-based grouping of progenies for homogenous field evaluation. Similarly, genome-based grouping within ploidy classes is recommended to allow proper evaluation of progenies according to targeted postharvest utilization. Thus, ploidy analysis by flow cytometry and genome determination by RAPD open prospects for enhancing breeding efficiency in the development of triploid bananas or plantains

Screening African Rice (Oryza glaberrima) for Tolerance to Abiotic Stresses: II. Lowland Drought

Drought is a major constraint to rice (Oryza spp.) production in sub-Saharan Africa. Oryza glaberrima Steud., the cultivated rice species that originated from West Africa, is well-adapted to its growing ecologies. This study was initiated to identify promising O. glaberrima accessions tolerant to lowland drought stress from the 2106 accessions held at the AfricaRice Genebank. Screening was done over a 3-yr period in West Africa using standardized protocol and involved evaluating for grain yield under drought and/or irrigated conditions, selecting the high-yielding lines, and repeating the testing with the newly selected lines. Four accessions (TOG 7400, TOG 6520, TOG 6519-A, and TOG 7442-B) with consistently higher grain yield under drought stress and irrigated conditions were selected. These four accessions originated from three countries in West Africa, namely, Ghana, Liberia, and Nigeria. The selected O. glaberrima accessions could be used as donors in breeding for drought tolerance in rice