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Wide variability does not exist in okra [Abelmoschus esculentus (L.) Moench], requiring induction of genetic variability. Mutagenesis creates desired variability among genotypes without altering the agronomic base which is sometimes difficult to induce using other breeding methods. Seed germination/seedling emergence and seedling growth were evaluated under laboratory and field conditions by imposing 300 to 1000 Gy (Gray, the SI unit of radiation) gamma radiation to determine median lethal (LD50) and median growth reduction (GR50) doses with Co60gamma rays. The LD50 and GR50 doses varied for both growing conditions. More than 80% of seed exposed to the LD50 dose of gamma radiation in the laboratory did not emerge under field condition. The LD50 and GR50 doses of gamma radiation determined under field condition exhibited close correspondence and presented a reliable picture regarding lethality and injury in the M1 generation (the first generation from the irradiated seed). The R2 for the linear model for seedling emergence, shoot and root length, fresh and dry weight of seedlings under field condition were 0.908, 0.902, 0.911, 0.983 and 0.972, respectively. Determination of the LD50/GR50 is important to optimize the radiation dose to isolate desired utilizable mutants. Dose optimization should be determined through use of LD50 and GR50 under field condition. The gamma radiation dose between 350 Gy and 450 Gy was optimum to create desirable mutants in okra. The optimal dose could induce a higher rate of mutation with little biological damage in succeeding generations of okra. [ABSTRACT FROM AUTHOR]

Micronutrient malnourishment is a problem in developing countries, most especially among women and preschool children. Breeding okra [Abelmoschus esculentus (L) Moench] for high seed contents of micronutrients in a high pod yielding background may contribute to correcting this problem. This requires evaluating micronutrients association with agro-morphological and seed elemental traits. Field evaluations were conducted with 20 okra landraces during 2016 and 2017 at Abeokuta, Nigeria. Genotypic correlation, regression and path analyses were performed to determine key driving traits of high pod yield, and seed iron and zinc contents. There were significant differences in landraces in the agronomic and nutritional traits. Correlation analysis indicated a positive, significant, relationship between plant height at flowering and maturity, and number of seed per pod with pod yield. Regression analysis indicated number of pods per plant was the most important trait for pod yield improvement as it retained the highest coefficient of determination. Path analysis identified tall plants with more pods be used for improvement of pod yield. Heavier seed should be used for improvement of seed iron content, seed magnesium and potassium contents should be targeted to achieve seed zinc content improvement. Plant height and number of pods per plant should be focused on in improvement of pod yield in okra. The 100-seed weight could serve as a major selection criterion to achieve increased seed iron content. Determination of other yield-related, and nutritional, traits might provide additional insight into improving pod yield and seed elemental minerals in okra. [ABSTRACT FROM AUTHOR]

The type of production environment can affect agronomic performance of West African okra [Abelmoschus caillei (A.Chev) Stevels] breeding lines and their progenies. The study was conducted to (1) compare agronomic performance of West African okra lines and F2 populations under upland and bottomland environments, (2) identify sources of genes with potential to improve pod yield, (3) estimate genetic and phenotypic correlations for evaluated traits, and (4) estimate expected response to selection for pod yield and other agronomic traits through intergeneration correlation and regression. Twenty-three genotypes (9 F2 populations and their corresponding 14 parents) were grown in two production environments at the research farms of the Federal University of Agriculture, Abeokuta, Nigeria. Results were analyzed using principal component analysis, correlation and regression analyses. Unique trait profiles in genotypes responses to production environments occurred. Most genotypes indicated adaptation to the bottomland environment by reducing days to physiological maturity. Hybrid AGA97/066/5780 × NGAE-96–-0062-2, which combines early maturity with superior expression of pod yield between production environments, may be used to improve earliness in West African okra. Principal component analysis revealed three major factors that explained more than 66% and 69% of interrelation among traits in upland and bottomland, respectively. Changes of genotypic correlations between pod yield and other agronomic traits occurred between environments indicating the influence of environmental factors to trait correlation. A significant, positive correlation, and regression coefficients, between parents and the F2 generation for pod yield occurred between production environments, indicating the effectiveness of selection for pod yield in the early segregating generation. Generally, bottomland production environment offered a higher potential for agronomic trait expression in breeding lines and F2 population of West African okra. [ABSTRACT FROM AUTHOR]

Drought causes severe reduction in okra [Abelmoschus esculentus (L.) Moench] yield. However, the impact of drought on okra physiology has been impeding breeding where relative degrees of tolerance need to be quantified. The okra, cv. NHAe 47-4, was exposed to 25, 50, 75, or 100% field capacity (FC) to impose water deficit for 5 or 10 days, at the vegetative (V), vegetative and reproductive (VR), or reproductive (R) stages, and effects on growth and yield, leaf relative water content (LRWC), leaf photosynthetic pigments, proline, and cysteine accumulation assessed. Simulated drought reduced LRWC, leaf chlorophyll content, biomass accumulation, and okra growth compared to the control (100% FC). The effect was more severe on plants subjected to water deficit of 10 days duration at vegetative and reproductive stages at 25% FC. Plants treated at the vegetative stage alone recovered faster than those treated at the reproductive stage alone and treatment at the two stages together. After recovery, plants exposed to water deficit at the vegetative stage alone produced more chlorophyll than the control. Okra plants exposed to water deficit produced more proline, cysteine, and carotenoids than untreated plants, with the least recorded in control, and the response varied based on duration and different FC at every growth stage. The highest values for proline and carotenoids were at 25% FC for 10 days duration at every growth stage. Plants exposed to water deficit produced more fruit than the control, especially those exposed at the vegetative stage only. Under prolonged water deficit for 10 days at the vegetative stage, there was 90.95, 70.80, and 131.18% increase in fruit yield at 25, 50, and 75% FC, respectively, compared to the control. Soil water maintained at 75% FC throughout the growing period enhanced fruit production compared to other field capacities including control. Okra response depends on water deficit severity, duration, and growth stage. Production of proline and carotenoid could be a strategy employed by okra plants for tolerance under water deficit. [ABSTRACT FROM AUTHOR]

Water deficit in semi-arid areas is a limiting factor affecting crop production and quality. The Middle East suffers from low rainfall and high temperatures. Foliar fertilization with Tecamin max®, compensates for nutrient deficiency by roots due to water deficit. The water soluble fertilizer Tecamin max® was applied to foliage to determine effects on morphological traits of the okra [Abelmoschus esculentus (L.) Moench], cvs. Samara and Ptira, under water deficit. There were irrigation levels of 50 and 100% based on field capacity, and concentrations of Tecamin max® (0, 2.5 and 5.0 mL∙L−1). 'Samara' had the tallest plants (115.50 cm), most leaves/plant (~ 31), longest time to flowering (30.44 days), most fruit/plant (51.38) and highest total yield (1.120 kg∙m−2). The 100% irrigation level produced values for plant height (107.66 cm), number of branches/plant (12.72), number of leaves/plant (29.77), total leaf area (492.00 dm2/plant), number of fruit/plant (46.27), and total yield (0.982 kg∙m−2) that were higher than for the 50% level. The 2.5 mL∙L−1 application of Tecamin max® produced plants that were 110.75 cm tall, having 14.25 branches/plant, a total leaf area of 529.33 dm2/plant, ~ 48 fruit/plant and total yield of 1.056 kg∙m−2 that were greater than for the other treatments. Foliar application of Tecamin max®, regardless of cultivar, improves vegetative growth under normal, and water deficit, conditions. [ABSTRACT FROM AUTHOR]

Okra [Abelmoschus esculenntus (L.) Moench] production is constrained by insect pests. Botanical insecticide may be an alternative to synthetics in pest management. Insecticide of all types can affect the physiology of crops. Three botanical insecticides, one synthetic insecticide, and two solvents, applied at three concentrations, were evaluated to determine effects on nutrient and antinutrient composition of okra. The materials were extracted on a weight/volume basis. The highest Ca, K, and Cr contents were in the botanical Morinda lucida (Benth) when tissues were extracted with 80% ethanol. The highest magnesium, iron, and zinc contents were in the botanical Vernonia amygdalina (Delile) when tissues were extracted with water at 90% concentration. The highest Mn and P contents were in M. lucida when botanical tissues were extracted with 90% ethanol and V. amygdalina when botanical tissues were extracted with water at 80%, respectively. No insecticide, the botanical V. amygdalina tissues extracted with 85% ethanol, the botanical M. lucida tissues extracted with 80% ethanol, and M. lucida tissues extracted with 90% ethanol produced the highest total phenolic, total flavonoid, flavonol, and tannin contents, respectively. The highest phytate and oxalate contents were okra treated with the botanical Andrographis paniculata (Burm. F.) tissues extracted with water at 90%. The highest 2,2-diphenyl-1-picrylhydrazyl content and total antioxidant capacity were in okra treated with M. lucida tissues extracted with 90% ethanol and M. lucida tissues extracted with water at 90%, respectively; okra treated with the botanical V. amygdalina tissues extracted with water at 85% had the highest ferric reducing power and metal chelating activity. Most botanicals supported high yield/plot. The effect of pesticide on nutrient composition of okra varied, with most botanicals producing higher nutritional values and yield. These botanicals appear to be beneficial for pest management. [ABSTRACT FROM AUTHOR]

Conservation of okra [Abelmoschus esculentus(L.)Moench] germplasm is mainly by seed storage in gene banks. Efficient management of seed collections, especially under tropical conditions, requires the ability to quantify and predict seed viability during storage. To quantify longevity of okra seed for purposes of viability prediction, two controlled deterioration (CD) experiments were conducted. In the first experiment, seed of six accessions of okra were stored at 45°C and 60% relative humidity (RH), and germination determined at 0, 3, 5, 10, 20 35, 50, 70, and 100 days to estimate probit seed longevity parameters. Mean probit seed longevity (P50) was 102.59 ± 38.21 days, indicating that okra seed are long-lived compared to a longevity marker species,Brassica napus(L.). In the second experiment, constants of a model for predicting viability were determined for okra seed stored for 300 days at 45°C and 2.19 to 12.9% seed moisture content (MC). The fit of log σ and log MC wasR2= 0.90 when log σ data for okra seed dried below 4.09% MC were not included in the fit. Estimates of derived viability constants wereKE= 6.659 andCW= 2.448. Estimated viability constants should be used for viability predictions under typical tropical ambient storage and practical gene bank storage conditions. [ABSTRACT FROM AUTHOR]

Continuous use of previous generation acaricides in okra [Abelmoschus esculentus(L.) Moench] has increased resistance to pesticides and pest resurgence. The project was undertaken to evaluate a new acaricide, fenazaquin 10 EC, for effective control of two-spotted spider mites [Tetranychus urticaeKoch (Acari: Tetranychidae)] in pot culture and under field conditions. Fenazaquin was used at 75, 100, 125, or 150 g·ha−1a.i. and compared with the standard acaricide dicofol 18.5 EC at 250 g·ha−1a.i. and an untreated control. The adulticide bioassay, ovicidal action toT. urticaeand safety of Dwarf honey bees (Apis floreaFabricius), was performed under laboratory conditions. Pot culture and two field trials were conducted to evaluate efficacy. Impact on okra yield and phytotoxicity were determined. The LC50was 1.440 mg·L−1and LT50at 1.50 mg·L−1was ˜8 hours. Fenazaquin produced more than 70% egg mortality in all doses forT. urticae. Fenazaquin at 125 and 150 g·ha−1a.i. caused the highest reduction in numbers of mites in pot culture and field experiments. Fruit yields (9.89 Mt·ha−1, 10.59 Mt·ha−1) and cost–benefit ratio (1:3.25, 1:3.48) were higher in fenazaquin-treated plants at 150 g·ha−1a.i in field experiments. No test doses were phytotoxic and all doses were relatively safe to Dwarf honey bees. [ABSTRACT FROM PUBLISHER]

Okra, Abelmoschus esculentus (L.) Moench, is attacked by the adult chrysomelid flea beetles, Podagrica spp. Information on physiological disruptions that occur due to flea beetle infestation affecting okra yield loss is incomplete. Screenhouse and field experiments were established to examine the effects of insect populations on leaf abscission, chlorophyll concentration, and biomass partitioning. Okra plants were grown in wire mesh screen cages and artificially infested with flea beetles, P. uniforma Jac., at population densities of 0, 5, 10, 20, 30, and 40 pairs per plant at 3 weeks after sowing (1 pair = 1 male and 1 female). In both experiments, okra plants had increased leaf abscission up to 100% at the 40-pair level in response to P. uniforma–induced injury. There were no significant differences in chlorophyll concentrations of plants at 0-, 5-, and 10-pair levels of infestation, suggesting the use of a compensatory mechanism by plants; at the 20-pair level a significant reduction occurred. Number of leaves per plant, shoots, roots, and dry fruit and total dry matter yield were reduced with infestation above the 20-pair level. More biomass was partitioned into roots at the 5- and 10-pair levels, but insect damage at populations beyond these levels completely suppressed the plant's ability to partition biomass. Dry fruit yields were reduced more than 50% when beetle populations increased beyond 20 pairs in both experiments. There was a correlation between insect density and number of leaves per plant and shoot, root, dry fruit, and total dry matter yield. The reduction in okra leaf production and chlorophyll content and increase in leaf abscission as a result of flea beetle infestation apparently resulted in a reduction in dry matter yield. The 20-pair level appeared to be the damage threshold of the insects. Physiological disruptions induced by the flea beetle at this level overcame the plants' ability to compensate for damage and caused significant reductions in leaf production, chlorophyll content, and dry matter yield and an increase in leaf abscission. [ABSTRACT FROM AUTHOR]

Okra [Abelmoschus esculentus (L.) Moench] is susceptible to at least 19 plant viruses with Okra mosaic virus (OkMV) being reported to be the most severe. Alternative host plants have been suspected to harbor OkMV which have contributed in its transmission. A study was carried out to determine the incidence of OkMV in weed species found near cultivated okra. Weed species growing around okra field, and exhibiting virus, or virus-like disease, symptoms were sampled and serologically analyzed to determine whether they harbored OkMV. Vector transmission tests were carried out with Aphis craccivora, A. spiraecola, Podagrica unifoma, P. sjostedti and Syagrus spp. to determine if the virus was insect-transmitted from the weeds to healthy okra and indicator plants. In the second experiment, healthy okra plants were inoculated with OkMV, at 14, 21, and 28 days after emergence and the effect of OkMV on yield components was estimated. Presence of OkMV in some weed samples was confirmed by symptom expression, host range, and serology. Leaf extract from the weeds produced symptoms on at least two common indicator hosts upon mechanical inoculation. Datura spp. exhibited the greatest ability to harbor OkMV. Cucumber mosaic virus (CMV; genus Cucumovirus), a non-persistently transmitted virus was isolated as a result of differential transmission tests with candidate vectors of CMV from Datura sp. The effect of OkMV infection on okra growth and yield varied with time of inoculation. There was a positive correlation between fruit weight and numbers of fruit for all inoculation times. There was reduction in yield components due to infection with OkMV in all time of inoculation. [ABSTRACT FROM AUTHOR]

Small-scale vegetable growers need investment and cost guidelines for irrigation systems in order to evaluate the economics and profitability of growing crops with irrigation. Growth, yield, and economics of producing okra and amaranth under four irrigation methods—basin, drip, furrow, and sprinkler—were evaluated. The experiment was conducted at the Teaching and Research Farm at Obafemi Awolowo University, Ile-Ife, Nigeria, on a sandy loam soil during the dry season. Plant heights and leaf area index were measured at different stages of plant growth; yield was measured at maturity. Fixed and variable costs of all the methods were estimated using results from field experiments and data collected from 50 farms, as well as from the State Agricultural Development Authority. Economic analyses of crop growth under the four methods were carried out. Results indicated that plants receiving drip and sprinkler irrigation had significantly higher yield than furrow and basin for both amaranth (Amaranthus cruentus L.) and okra [Abelmoschus esculentus (L.) Moench]. However, drip irrigation had higher water use efficiency than the sprinkler system for both crops; for okra, water use efficiency with furrow irrigation was significantly higher than that for basin irrigation. Partial budgeting indicated that all systems were profitable. However, basin irrigation had the least cost-benefit ratio and drip had the highest. Economic analyses indicated that a minimum of a 2½- and 3-year period would be needed to pay off fixed assets for drip irrigation for amaranth and okra, respectively. It is recommended that drip irrigation be used for production of amaranth and okra, especially where labor is neither readily available nor cheap. [ABSTRACT FROM AUTHOR]

The high evaporative demand and deep percolation losses in the tropics require adequate irrigation and agronomic management practices that will improve crop water use efficiency in okra [Abelmoschus esculentus (L.) Moench]. Differences among okra varieties in growth indices and yield for plants treated with three irrigation intervals, with or without mulching with grass, were investigated. The variety NH99 produced the highest yield (8.2 Mt·ha-1). Irrigation at 30% moisture depletion produced the highest leaf area, stem diameter, and yield for plants in mulched and unmulched plots and also produced higher plant height and dry matter for mulched plots. Mulching and proper irrigation scheduling should be done to increase yield and save water and improve okra yield. [ABSTRACT FROM AUTHOR]

Understanding how an enterprise fits within a market chain, and the numerous links that connect all participants and transactions involved in the movement of agricultural goods from farm to consumer, allows better decisions to be made on how to produce most efficiently. Problems encountered by participants in the okra [Abelmoschus esculentus (L.) Moench] market chains were identified. The rapid market survey methodology was employed for the collection of primary data. Data were analyzed using descriptive statistics, budgetary analysis, and pairwise ranking. The main participants in the industry were producers, traders (wholesalers and retailers), and transporters, while the main governmental agency is the Osun State Agricultural Development Programme (OSSADEP). Common problems confronting the main participants in the industry were lack of access to funds, especially from formal institutions. Technical assistance needs to he provided in production and marketing of okra, and access to funds has to be improved to participants to improve the market chain. OSSADEP could play the role of co-coordinator among the participants in the industry. [ABSTRACT FROM AUTHOR]