Phenotypic variation in the agronomic and morphological traits of Pisum sativum L. germplasm obtained from different parts of the world

A total of 286 genotypes were collected from 39 countries of the world and were evaluated to determine the phenotypic diversity for 17 quantitative traits. Higher degree of coefficient of variation were recorded for grain yield(-5) (52.46%), biomass(-5) (45.73%), fresh pod width(-10) (47.24%), dry pod weight(-1) (40.33%), plant height(-1) (35.25%), harvest index (32.70%) and number of branches(-5). Cluster-II clearly reflected that late genotypes were having lightest pods weight, shortest pod width, and pod length; low grain yield, biomass and harvest index. While genotypes in Cluster-III were in contrast to Cluster-II having heaviest pods weight, longest pods width and length, highest grain yield, biomass and harvest index. Higher PC(-1) values have been determined for days to flower initiation which consequently were contributing weighed positive to days to pods picking, days to flower completion, days to dry pod appearance, days to plant harvesting while negatively contributed to yield producing traits, indicating that late flowering pea germplasm emphasizes more on the vegetative growth and was low yielding. However, higher PC(-2) values have been obtained for number of branches(-5), grain yield and biomass while lower values for days to flowering, days to pods picking, days to flower completion, days to dry pod appearance and days to plant harvesting confirming the fact that early genotypes were high yielding.     

Growth and yield of groundnut (Arachis hypogaea L.) as influenced by weed management practices and Rhizobium inoculation

Groundnut (Arachis hypogaea L.) productivity in India is low, because of many problems beset in its cultivation. One of the serious problems are weeds. Groundnut yield losses due to weeds have been estimated as high as 24 to 70 percent. This has created a scope for using herbicides in groundnut crop. A field investigation was carried out during kharif (rainy) season of 2001-2002 on a sandy loam soil at College Agronomy Farm, B.A. College of Agriculture, Gujarat Agricultural University, Anand, India to study the effect of weed management practices and Rhizobium inoculation on growth and yield of groundnut (Arachis hypogaea L.). Ten weed control treatments, comprising four treatments of sole application of fluchloralin, pendimethalin, butachlor and metolachlor, respectively each applied at 1.0 kg ha(-1); four treatments comprising of an application of the same herbicides at the same levels coupled with one hand weeding at 30 DAS; one weed-free treatment (hand weedings at 15, 30, 45 DAS); and one unweeded control. All 10 treatmets were combined with and without Rhizobium inoculation (i.e. a total of 20 treatment combinations) under a factorial randomized complete block design (FRBD) with four replications. Minimum weed dry matter accumulation (70 kg/ha) with higher weed control efficiency (90.70%) was recorded under an integrated method i.e. pendimethalin at 1.0 kg ha(-1) + hand weeding at 30 DAS, which also resulted in maximum pod yield (1773.50 kg ha(-1)). This treatment was comparable to fluchloralin applied at 1.0 kg ha(-1) combined with hand- weeding at 30 DAS. Weedy conditions in the unweeded control treatment reduced pod yield by 29.90-35.95% as compared to integrated method. Significantly higher pod yield was obtained with Rhizobium inoculation than the mean value of all treatments without inoculation. For most agronomical parameters examined, Rhizobium inoculation and weed control treatments were independent in their effect.     

Phenotypic variation in the agronomic and morphological traits of <Emphasis Type="Italic">Pisum sativum</Emphasis> L. Germplasm obtained from different parts of the world

A total of 286 genotypes were collected from 39 countries of the world and were evaluated to determine the phenotypic diversity for 17 quantitative traits. Higher degree of coefficient of variation were recorded for grain yield⁻⁵ (52.46%), biomass⁻⁵ (45.73%), fresh pod width-10 (47.24%), dry pod weight⁻¹⁰ (40.33%), plant height⁻¹ (35.25%), harvest index (32.70%) and number of branches⁻⁵. Cluster-II clearly reflected that late genotypes were having lightest pods weight, shortest pod width, and pod length; low grain yield, biomass and harvest index. Width, and pod length; low grain yield, biomass and harvest index. While genotypes in Cluster-III were in contrast to Cluster-II having heaviest pods weight, longest pods width and length, highest grain yield, biomass and harvest index. Higher PC₋₁ values have been determined for days to flower initiation which consequently were contributing weighed positive to days to pods picking, days to flower completion, days to dry pod appearance, days to plant harvesting while negatively contributed to yield producing traits, indicating that late flowering pea germplasm emphasizes more on the vegetative growth and was low yielding. However, higher PC₋₂ values have been obtained for number of branches⁻⁵, grain yield and biomass while lower values for days to flowering, days to pods picking, days to flower completion, days to dry pod appearance and days to plant harvesting confirming the fact that early genotypes were high yielding.     

Yield response of cowpea, Vigna unguiculata L. (Walp), to infestation of Aspavia armigera F. (Hem., Pentatomidae)

Abstract:  Yield-related responses of cowpea plants to artificial infestation of Aspavia armigera , at the onset of podding, at different densities, 0, 1, 2, 4, 8, 16 and 32 pairs per cage were studied on cowpea in caged pots and field plots. With increasing insect density there was a corresponding significant increase (P < 0.05) in pod and seed damage, and reduction in pod length, numbers of pods per plant and seeds per pod, seed weight and total yield. Pod production was significantly higher (P < 0.05) in infested plants than in the control; at 1- and 16-pair levels, pod production increased by 75% and 81% over the uninfested control in the pot and field experiments respectively. Then again, with increase in insect density there was a progressive high-magnitude increase in pod abortion reaching 252.6% and 200% at the 32-pair level on potted and field cowpea, respectively, resulting in drastic reductions in the number of harvestable pods. Cowpea compensation mechanism was lost completely as insect population increased. The lowest density of A. armigera at which significant reduction (P < 0.05) occurred in total seed yield compared with the control was one pair. The relationship between insect density and pod damage, and yield was best described by a quadratic + linear fit, while that between insect density and seed damage was best fit as polynomial with very high significant r -values. Chi-squared analysis showed that the models derived from pot and field data were similar.     

Yield,development, and quality response of dual‐toxin Bt cotton to Helicoverpa spp. infestations in Australia

To verify current thresholds for Bollgard II^® cotton in Australia, the impact of Helicoverpa spp. (Lepidoptera: Noctuidae) larvae on yield, development, and quality under various infestation intensities and durations, and stages of growth, was tested using small plot field experiments over two seasons. Infestation with up to 80 eggs m^?1 of Helicoverpa armigera (Hübner) and Helicoverpa punctigera Wallengren showed that species, infestation level, and stage of growth had no significant effect on yields of seed‐cotton or lint and on maturity and fibre quality. The duration of infestation of white flowers with H. punctigera neonates (maximum of every day for up to 4 weeks) had no impact on the yield of seed‐cotton or lint, maturity, and fibre quality, but when 100% of flowers were infested (compared with 0 or 50%), seed‐cotton and lint yields were significantly reduced and maturity was delayed. Infestation with up to 18 medium H. armigera larvae m^?1 at several plant stages did not significantly affect yields of seed‐cotton and lint, maturity, and fibre quality. A heliocide spray applied on a commercial farm at the current threshold resulted in a significantly higher lint yield, compared with a farm where no spray was applied. In conclusion, Bollgard II^® cotton is highly resistant to Helicoverpa spp. infestation.     

大豆小区产量及其相关性状QTL间的上位性和环境互作效应

以晋豆23栽培大豆(Glycine max)为母本、灰布支黑豆(ZDD2315,半野生大豆)为父本衍生出447个RIL群体,通过构建SSR遗传图谱及利用混合线性模型分析方法,对2年大豆小区产量及主要植物学性状进行QTL定位,并作加性效应、加性×加性上位互作效应及环境互作效应分析。结果显示,共检测到12个与小区产量、单株粒重、单株茎重、单株粒茎比、有效分枝、主茎节数、株高和结荚高度相关的QTL,分别位于A1、A2、H_1、I、J_2和M连锁群上。其中小区产量、株高、单株粒重、有效分枝和主茎节数均表现为遗传正效应,即增加其性状的等位基因来源于母本晋豆23。同时,检测到11对影响小区产量、单株粒重、单株茎重、株高和结荚高度的加性×加性上位互作效应及环境互作效应的QTL,发现22个QTL与环境存在互作。实验结果表明,上位效应和QE互作效应对大豆小区产量及主要农艺性状的遗传影响很大。进行大豆分子标记辅助育种时,既要考虑效应起主要作用的QTL,又要注重上位性QTL,这样有利于性状的稳定表达和遗传。     

Standardization of cage techniques to screen chickpeas for resistance to Helicoverpa armigera (Lepidoptera: Noctuidae) in greenhouse and field conditions

Because of variations in insect populations and staggered flowering of chickpea, Cicer arietinum L., genotypes, it is difficult to compare the genotypic performance across seasons and locations. We standardized a cage technique to screen chickpeas for resistance to Helicoverpa armigera (Hübner). Leaf feeding by the larvae was significantly lower on ICC 506 than on ICCC 37 when the seedlings were infested with 20 neonates per five plants at 15 d after seedling emergence or 10 neonates per three plants at the flowering stage. Maximum differences in pod damage were observed when the plants were infested with six third-instar larvae per three plants in the greenhouse, and with eight larvae per plant under field conditions. Larval weights were significantly lower on ICC 506 than on ICCC 37 across growth stages and infestation levels. At the podding stage, percentage of reduction in grain yield was significantly greater on ICCC 37 and Annigeri than on ICCV 2 and ICC 506. The no-choice test can be used to screen segregating breeding material and mapping populations for resistance to H. armigera. It also provides useful information on antibiosis mechanism of resistance to H. armigera.     

Effects of Aphis fabae Scop, and of its attendant ants and insect predators on yields of field beans (Vicia faba L.)

Predators (mainly coccinellid adults and larvae and syrphid larvae), although few, were important in decreasing numbers of Aphis fabae on a small plot of field beans during the early stages of infestation in a year favourable to the aphid. At the same time, ants (Lasius niger L.), attending aphids on other plants on the same plot, effectively protected the aphids from predators for about 2 weeks, enabling the attended aphids to multiply faster than the unattended. When all aphid populations started to decline, predators became more numerous and accelerated the decline on both sets of plants. Bean plants without aphids yielded fifty-six seeds per plant; those with aphids but free from ants gave seventeen; and those with ant-attended aphids, eight seeds per plant. The damage and loss of yield was caused by the large aphid populations that developed when the pods were maturing, and not by the fewer aphids present when the plants were in flower. It appears that small, temporary infestations during flowering might increase the yield of field beans.     

Assessment of transpiration efficiency in peanut (Arachis hypogaea L.) under drought using a lysimetric system

Transpiration efficiency (TE) is an important trait for drought tolerance in peanut ( Arachis hypogaea L.). The variation in TE was assessed gravimetrically using a long time interval in nine peanut genotypes (Chico, ICGS 44, ICGV 00350, ICGV 86015, ICGV 86031, ICGV 91114, JL 24, TAG 24 and TMV 2) grown in lysimeters under well-watered or drought conditions. Transpiration was measured by regularly weighing the lysimeters, in which the soil surface was mulched with a 2-cm layer of polythene beads. TE in the nine genotypes used varied from 1.4 to 2.9 g kg⁻¹ under well-watered and 1.7 to 2.9 g kg⁻¹ under drought conditions, showing consistent variation in TE among genotypes. A higher TE was found in ICGV 86031 in both well-watered and drought conditions and lower TE was found in TAG-24 under both water regimes. Although total water extraction differed little across genotypes, the pattern of water extraction from the soil profile varied among genotypes. High water extraction within 24 days following stress imposition was negatively related to pod yield ( r ²   =   0.36), and negatively related to water extraction during a subsequent period of 32 days ( r ²   =   0.73). By contrast, the latter, i.e. water extraction during a period corresponding to grain filling (24 to 56 days after flowering) was positively related to pod yield ( r ²   =   0.36). TE was positively correlated with pod weight ( r ²   =   0.30) under drought condition. Our data show that under an intermittent drought regime, TE and water extraction from the soil profile during a period corresponding to pod filling were the most important components.     

Use of plant residues for improving soil fertility, pod nutrients, root growth and pod weight of okra (Abelmoschus esculentum L)

The effect of wood ash, sawdust, ground cocoa husk, spent grain and rice bran upon root development, ash content, pod yield and nutrient status and soil fertility for okra (Abelmoschus esculentum L NHAe 47 variety) was studied. The five organic fertilizer treatments were compared to chemical fertilizer (400kg/ha/crop NPK 15-15-15) and unfertilized controls in four field experiments replicated four times in a randomized complete block design. The results showed that the application of 6tha(-1) of plant residues increased (P<0.05) the soil N, P, K, Ca, Mg, pH, and SOM; pod N, P, K, Ca, Mg and ash; root length; and pod yield of okra in all four experiments relative to the control treatment. For instance, spent grain treatment increased the okra pod yield by 99%, 33%, 50%, 49%, 65% and 67% compared to control, NPK, wood ash, cocoa husk, rice bran and sawdust treatments respectively. In the stepwise regression, out of the total R(2) value of 0.83 for the soil nutrients to the pod yield of okra; soil N accounted for 50% of the soil fertility improvement and yield of okra. Spent grain, wood ash and cocoa husk were the most effective in improving okra pod weight, pod nutrients, ash content, root length and soil fertility whereas the rice bran and sawdust were the least effective. This was because the spent grain, wood ash and cocoa husk had lower C/N ratio and higher nutrient composition than rice bran and sawdust, thus, the former enhanced an increase in pod nutrients, composition for better human dietary intake, increased the root length, pod weight of okra and improved soil fertility and plant nutrition crop. The significance of the increases in okra mineral nutrition concentration by plant residues is that consumers will consume more of these minerals in their meals and monetarily spend less for purchasing vitamins and mineral supplement drugs to meet health requirements. In addition, the increase in plant nutrition and soil fertility would help to reduce the high cost of buying synthetic inorganic fertilizers and maintain the long term productivity of soils for sustainable cultivation of okra.     

Mating disruption of pea moth (Cydia nigricana) in organic peas (Pisum sativum)

We appraised mating disruption (MD) to control pea moth, Cydia nigricana (Fabricius) (Lepidoptera: Tortricidae), by assessing male attraction to monitor traps, larval pod infestation, and larval age structure in pheromone‐treated and untreated grain pea fields [Pisum sativum L. (Fabaceae)], over a 5‐year period. Cellulose pheromone dispensers were manually attached to the top shoots of pea plants and released 540 mg ha^?1 day^?1 synthetic pheromone E8,E10‐dodecadien‐1‐yl acetate in a first test series (2000–2001) and ca. 4 200 mg pheromone ha^?1 day^?1 in a second series (2004–2006). The dispensers had a half‐life of about 30 days. Although male attraction to pheromone monitoring traps was largely suppressed at the edges and within MD fields in both test series, MD treatments did not reduce pod infestation in the open field in 2000 and 2001. In the 2004–2006 series, larval damage reduction was achieved in the majority of the trials but overall MD efficacy in the open field was only 61% and not significant. In contrast, in field cages placed within the experimental sites and supplied with unmated pea moths, MD control was consistently high and significant. There were no obvious differences in the larval age distribution in all MD and control treatments, suggesting that infestations started and developed further similarly. As a univoltine species, C. nigricana larvae stay in the soil of pea fields for hibernation and pupate. The following year, emerging adults disperse and fly to the closest pea crop. Combined emergence site and pea crop treatments were conducted over 2 years to include this early migration phase of C. nigricana adults. However, the emergence site treatments did not enhance MD‐control efficacy. We conclude that mating activity was only prevented in cage tests, whereas substantial mating occurred during the transit phase outside the pheromone‐treated fields either within non‐crop vegetation and/or at the edges of pheromone‐treated pea fields orientated upwind. Thus, resulting gravid female entry can be regarded as the major constraint to reliable MD control.     

The influence of plant age on tolerance of rice to injury by the rice water weevil,Lissorhoptrus oryzophilus (Coleoptera: Curculionidae)

For most plant species, tolerance to many types of herbivory increases as plants age, but the applicability of this pattern to root herbivory has not been tested. Injury to roots of rice plants by larvae of the rice water weevil, Lissorhoptrus oryzophilus Kuschel, causes severe reductions in yields in the United States. It is generally thought that young rice plants, because their root systems are smaller, are less tolerant than older plants of root feeding by L. oryzophilus. Field experiments were conducted to test this hypothesis. Plots of rice (4.7 to 6.5 m2) were established and subjected to natural infestations of L. oryzophilus larvae. A soil insecticide was applied to plots at different times during the tillering phase of rice in order to manipulate the timing of weevil infestation. The impact of these treatments (timings of insecticide applications) was assessed by comparing relationships between yield loss and larval pressure for each treatment using analysis of covariance. Yield losses ranged from 13% to over 40% in plots not treated with insecticide. Patterns of yield losses from plots treated with insecticide at different times were best explained by the hypothesis that yield loss is determined both by the age of plants infested and by the size of larvae infesting plants. Young plants appear to be less tolerant than older plants, and feeding by large larvae appears to be more deleterious than feeding by smaller larvae. Management practices that delay infestation of rice by L. oryzophilus until plants are older may be an important component of management programmes for this pest.     

水分亏缺对蚕豆光合特性影响的初步研究

本文报道了蚕豆现蕾至饱荚期不同时间土壤水分亏缺情况下的光合特性、光合产量及蚕豆水分亏缺敏感期。蚕豆现蕾后给予土壤干旱处理,光合速率、叶绿素含量、叶面积、气孔开度、生物产量及籽粒产量下降,但气孔密度和呼吸速率增加。水分亏缺使叶片光饱和点由50kLx降至30kLx,气孔开度日变化呈单峰(9—11时)曲线。始荚至盛荚期对土壤干旱最敏感,此期是蚕豆灌水的关键时期。     

Effect of sorghum phenology on the control of Chilo partellus with Nosema marucae (microspora: Nosematidae)

An aqueous suspension of Nosema marucae spores was sprayed on foliage of sorghum plants that had been infested with neonate Chilo partellus larvae at 3, 5, 7 and 9 weeks after (plant) emergence (WAE). These periods corresponded to plants at the tillering, early booting, soft dough and late maturation phenological stages, respectively. The extent of borer infestation and plant damage was monitored until crop harvest, and compared with plants which had been similarly infested but not sprayed with the pathogen, and with plants in insect‐free control plots. When applied early, infestation with neonate borer larvae caused most damage to the plants and the greatest reduction in yield in the untreated plots. Early treatment with N. marucae spores at 3 and 5 WAE resulted in the greatest reduction in damage to plants and the highest improvement in yield of seeds. It is apparent, therefore, that for maximum crop protection the microsporidian needs to be applied when sorghum is in an early phenological stage.     

Comparing the Effects of Rust on Plot Yield, Plant Yield, Yield Components, and Vegetative Parts of Soybean

To determine the plant variable for coupling a disease model to a soybean growth model, effects of soybean rust (caused by Phakopsora pachyrhizi) on soybean were quantified at four levels: vegetative parts, yield components, plant yield, and plot yield. Path analysis was conducted to determine the most correlated components to disease in each level. The responses of vegetative parts, such as shoot weight and branches/plant, to disease effects were inconsistent among cultivars. Yield components responded consistently to disease effects among the cultivars, indicated by the high values of correlation coefficients between disease and the components. Path coefficients indicated that reduction of 100-seed weight was the most important cause of yield loss in this level. No significant within-plant compensation was detected using path coefficient analysis except for that between pod length to pod width. The most consistent response to disease effect was at population level. Correlation of disease to plant yield was as significant as these to plot yield. Correlations between disease and these plant levels were in the order of plot yield, plant yield, yield components, and vegetative parts. Regression between plot yield and green leaf area duration (GLAD) from flowering to seed full size was highly significant (P < 0,001). This study suggests that green leaf area at population level was the best variable for coupling disease model to crop model.     

Influence of weeding regimes and pearl millet genotypes on parasitism of the Oriental armyworm, <Emphasis Type="Italic">Mythimna separata</Emphasis>

We studied the effect of four weeding regimes (weed free, one manual weeding, one manual weeding+atrazine, and a weedy check) on larval density and leaf defoliation in four pear millet genotypes by the larvae of Oriental armyworm, Mythimna separata. Data were also recorded on the extent of larval parasitism under different weeding regimes, and the parasitoids involved. The leaf damage and larval densities were lower in weed free plots as compared to the weedy plots. This was also reflected in grain yield, as maximum grain yield was recorded in weed-free plots as compared to the weedy plots. Seven parasitoids (Cotesia ruficrus, Metopius rufus, Sturmiopsis inferens, Palexorista solemnis, P. laxa, Carcelia sp., and the entomopathogenic nematode Neoplectana sp. were recorded from M. separata larvae, of which M. rufus, Carceliasp., and Neoplectanasp. were the most abundant. Parasitism by M. rufus was greater in plots with a weed cover and least in weed-free plots, while parasitsm by Carcelia sp. was lower in plots with one hand weeding than in weedy plots. Numerically, parasitism by Neopletana sp. was low in plots treated with atrazine, and maximum in plots weeded manually. Therefore, the minimum level of weeding, which does not affect the crop adversely should be undertaken to promote the biological control of M. separata in pearl millet.     

Impact of yellow mite (Polyphagotarsonemus latus [Banks]) density on host's (Corchorus capsularis L.) phenology and assessment of yield loss under field conditions

Yellow mite, Polyphagotarsonemus latus [Banks] (Acari: Tarsonemidae) is one of the major pests of jute crops (Corchorus capsularis L.) in Bangladesh. In this study, indigenous varieties of jute were used for treatments, namely, CVL‐1, CVE‐3, BJC‐7370 and BJC‐83. The paired plot treatments (treated and untreated controls) were laid out under field conditions. The effects of yellow mite were studied at three stages of the jute plants: 60 days after sowing (DAS), 90 DAS and 120 DAS. A higher number of mite stages was observed up to 90 DAS and then declined up to 120 DAS in var. BJC‐7370 among two other varieties, Deshi and Tossa. The percentage of infestation and damage indexes (scale 0–5) were measured to relate yellow mite injuries to the number of leaves, leaf area, fresh leaf weight, dry leaf weight, soluble solids, plant height, base diameter, fiber weight, stick weight, number of flowers per plant, number of pods, pod weight per plant, seeds per pod, seed weight and 1000 seeds' weight of plants infested at three different phenological stages. The highest fiber yield loss was found in the variety BJC‐7370 (59.75%), followed by BJC‐83 (55.56%), CVE‐3 (54.30%) and CVL‐1 (50.05). The highest stick yield losses were found in the following order: BJC‐7370 (54.54%) > BJC‐83 (51.17%) > CVL‐1 (43.68%) > CVE‐3 (37.80%) and BJC‐7370 (30.33%) > CVL‐1 (27.83%) > BJC‐83 (24.16%) > CVE‐3 (22.11%) for the highest seed yield under field conditions for Corchorus capsularis. High yellow mite population in untreated checks decreased plant growth and showed significant losses in yield production for the variety BJC‐7370.     

The effects of the infestation ratio of spiny bollworm (Earias insulana) and pink bollworm (Pectinophora gossypiella) on cotton yield grown in semi-arid region of Turkey

Abstract:  Field studies were conducted in Harran Plain, Turkey, to investigate the infestation of spiny bollworm (SBW) and pink bollworm (PBW) in cotton blind bolls during the period 1999–2001. Blind bolls left on the cotton plants after the harvest were collected, and the PBW and SBW larvae, which are the causes of infection were counted in the laboratory by splitting the bolls. The statistical methods reveal that the infestation ratio variable plays an important role in reducing cotton yield. The infestation ratio variable was found to be statistically significant in all models used. Different soil types may have little effects on yield. We also estimate elasticity of yield with respect to infestation ratio variable. A 1% increase in infestation ratio would reduce about 2.5–6% of cotton yield. Although the infestation ratio of cotton yield is inelastic, which means that the yield is less responsive to the infestation ratio, the elasticity is however an economically important indication because additional cost spent on pests will increase total cost thereby increasing the level where marginal revenue equals the marginal cost.     

Evaluation of responses of five cowpea (Vigna unguiculata (L.) Walp.) varieties to field infestation by major insect pests of cowpea

The study was conducted to evaluate yield response of five cowpea (Vigna unguiculata (L.) Walp.) varieties to field infestation and damage by major insect pests of cowpea. Three local varieties of cowpea, namely, Sokoto, Oloyin and Drum, and two International Institute of Tropical Agriculture (IITA) varieties, IT 90K-277-2 and IT90K-76, were planted on the Teaching and Research Farm of University of Agriculture, Abeokuta (UNAAB), Ogun State, Nigeria in September, 2006 and repeated in September, 2007. The experiment was laid out in Randomised Complete Block Design in split plots arrangement. Insecticidal spray constitutes the main plot while variety was the sub-plot. The main plot size was 19.4 m × 19 m and each of the sub-plot was 2.4 m × 3 m. The space between sub-plots was 1 m. Data from the sprayed plots were significantly (P < 0.05) higher than the unsprayed ones in the two seasons. Irrespective of season, the unsprayed plot of IT 90K-277-2 has a significantly (P < 0.05) high incidence of Ootheca mutabilis. The local variety, “Drum” has the highest incidence of flower thrip – Megalurothrips sjostedti in the two planting seasons. The highest mean number of peduncles/plant and pods/plant was in “IT 90K-277-2”. In both seasons, “IT90K-76” has a significantly (P < 0.05) lower number of damaged seeds and pods and “Oloyin” a significantly (P < 0.05) higher mean number of total pod sucking bugs. The grain yield was in the order IT90K-76 > Oloyin > IT 90K-277-2 > Sokoto > Drum.     

Bio-efficacy of different oil carriers in ultra low volume sprayer for management of pod borer,Helicoverpa armigera (Hübner) in pigeonpea ecosystem

A study was conducted to evaluate the bioefficacy of different oil carriers (sunflower oil, seamum oil, neem oil, mineral oil), sugar solution and water formulation to be used in ultra low volume sprayer (ULV) along with rynaxypyr 18.5 SC (Coragen) for the management of pod borer at the Agricultural Research Station, Gulbarga, Karnataka, India during the kharif season of 2011–2012. The results revealed that the sesamum oil carrier fits well with rynaxypyr 18.5 SC and recorded the lowest mean pod borer larval population after last spray (1.0 per five plants) the lowest pod damage (23.20%), grain damage (18.30%) and higher grain yield (9.43?q/ha) with a high B:C ratio of 3.64 in the plot sprayed with the sesamum oil carrier. The findings suggested that the sesamum oil carrier in ULV sprayer is suitable and practicable in pigeonpea ecosystem for effective management of pod borer with no risk of phytotoxicity, spray drift and operational difficulties. The foregoing studies indicated that the performance of sesamum oil carriers was superior to other carriers in terms of suppression of larval population, reduction in pod damage and harnessing higher yield.