Higher Seed Cotton Yield Research Articles

Relay cropping of wheat (Triticum aestivum L.) in cotton (Gossypium hirsutum L.) improves the profitability of cotton-wheat cropping system in Punjab, Pakistan.

Delayed sowing of wheat (Triticum aestivum L.) in cotton-based system reduces the productivity and profitability of the cotton-wheat cropping system. In this scenario, relay cropping of wheat in standing cotton might be a viable option to ensure the timely wheat sowing with simultaneous improvement in wheat yields and system profitability. This 2-year study (2012-2013 and 2013-2014) aimed to evaluate the influence of sowing dates and relay cropping combined with different management techniques of cotton sticks on the wheat yield, soil physical properties, and the profitability of the cotton-wheat system. The experiment consisted of five treatments viz. (S1) sowing of wheat at the 7th of November by conventional tillage (two disc harrows + one rotavator + two plankings) after the removal of cotton sticks, (S2) sowing of wheat at the 7th of November by conventional tillage (two disc harrows + two plankings) after the incorporation of cotton sticks in the field with a rotavator, (S3) sowing of wheat at the 7th of November as relay crop in standing cotton with broadcast method, (S4) sowing of wheat at the 15th of December by conventional tillage (two disc harrows + one rotavator + two plankings) after the removal of cotton sticks, and (S5) sowing of wheat at the 15th of December by conventional tillage (two disc harrows + two plankings) after the incorporation of cotton sticks in the field with a rotavator. The highest seed cotton yield was observed in the S5 treatment which was statistically similar with the S3 and S4 treatments; seed cotton yield in the S1 and S2 treatments has been the lowest in both years of experimentation. However, the S2 treatment produced substantially higher root length, biological yield, and grain yield of wheat than the other treatments. The lower soil bulk density at 0-10-cm depth was recorded in the S2 treatment which was statistically similar with the S5 treatment during both years of experimentation. The volumetric water contents, net benefit, and benefit-cost ratio were the highest in the S3 treatment during both years of experimentation. Thus, relay cropping of wheat in standing cotton might be a viable option to improve the soil physical environment and profitability of the cotton-wheat cropping system.

Title: Potassium application regulates nitrogen metabolism and osmotic adjustment in cotton (Gossypium hirsutum L.) functional leaf under drought stress

To evaluate the role of potassium (K) in maintaining nitrogen metabolism and osmotic adjustment development of cotton functional leaves to sustain growth under soil drought and rewatering conditions, the plants of two cotton cultivars Siza 3 (low-K sensitive) and Simian 3 (low-K tolerant), were grown under three different K rates (K0, K1, and K2; 0, 150, and 300kgK2Oha−1, respectively) and exposed to drought stress with 40±5% soil relative water content (SRWC). The drought stress was applied at flowering stage by withholding water for eight days followed by rewatering to a well-watered level (75±5% SRWC). The results showed that drought-stressed plants of both cultivars showed a decrease in leaf relative water content (RWC) and osmotic potential in the functional leaves and developed osmotic adjustment with an increase in the contents of free amino acids, soluble sugars, inorganic K, and nitrate as compared to well-watered plants. In drought-stressed plants, nitrogen-metabolizing enzyme activities of nitrogen reductase (NR), glutamine synthetase (GS), and glutamate synthase (GOGAT) were diminished significantly (P≤0.05) along with decreased chlorophyll content and soluble proteins. However, drought-stressed plants under K application not only exhibited higher osmotic adjustment with greater accumulation of osmolytes but also regulated nitrogen metabolism by maintaining higher enzyme activities, soluble proteins, and chlorophyll content in functional leaves as compared to the plants without K application. Siza 3 showed better stability in enzyme activities and resulted in 89% higher seed cotton yield under K2 as compared to K0 in drought-stressed plants, whereas this increase was 53% in the case of Simian 3. The results of the study suggested that K application enhances cotton plants’ potential for sustaining high nitrogen-metabolizing enzyme activities and related components to supplement osmotic adjustment under soil drought conditions.

FIELD EFFICACY OF SOME INSECTICIDES FOR CONTROL OF BOLLWORMS AND IMPACT ON NON-TARGET BENEFICIAL ARTHROPODS IN COTTON

SUMMARYLarvae of bollworms (Helicoverpa armigera (Hubner), Earias sp., Diparopsis watersii (Rothschild) and Pectinophora gossypiella (Saunders)) feed on cotton flower buds (squares) and developing bolls causing severe yield losses. While endosulfan, an organochlorine insecticide was the most effective and widely used insecticide for bollworm control in Ghana, it has been banned due to abuse and hazard to the environment. Field experiments were conducted during the rainy seasons of 2012 and 2013 to determine the efficacy of foliar insecticides tihan (spirotetramat + flubendiamide), thunder (imidacloprid + betacyfluthrin), belt expert (flubendiamide +thiaclopride), dursban 4EC (chlorpyrifos-ethyl), lambda super 2.5EC (lambda cyhalothrin) and polytrin C (profenophos + cypermethrin) for control of bollworms and their impact on non-target beneficial organisms in Ghana. All the insecticides tested lowered bollworm densities and boll damage but applications of tihan or belt expert alternated with thunder resulted in the highest seed cotton yield. The treatments generally did not lower populations of predators such as ladybird beetles and lacewings and could be included in an integrated pest management programme for bollworms in cotton. These results suggest that alternate applications of tihan or belt expert with thunder can be recommended as a replacement for endosulfan for control of cotton bollworms and improvement of cotton yield in Ghana.

Assessment of genetic variability and correlation analysis of seed and seed cotton yield attributing traits of tetraploid cotton genotypes (G. hirsutum L.)

The nature and magnitude of genetic divergence, variability and correlation were estimated in 110 extant varieties of cotton using Mahalanobis D 2 statistics by considering 20 quantitative characters to reveal a considerable amount of diversity in the material. The genotypes were grouped into ten clusters. Cluster I constituted a maximum number of accessions (80). The genotypes falling in cluster VIII (32.329) had the maximum divergence, which was closely followed by cluster IX (28.032), cluster X (23.674) and cluster I (15.717). The inter cluster distance was maximum between cluster VIII and IX (45.242) suggesting that the genotypes representing these clusters may be used as parents for future crop improvement programme. Traits like yield per plant, number of bolls per plant, sympodial length, number of sympodia per plant, dry matter of seedlings and plant height were the major contributors for genetic divergence. ANOVA revealed the presence of considerable amount of variability among the genotypes. High estimates of the genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were observed for yield per plant, number of bolls per plant, sympodial length, number of sympodia per plant, dry matter of seedlings and plant height. High heritability coupled with high genetic advance as per cent of mean was recorded for yield per plant, number of bolls per plant, dry matter of seedlings, sympodial length, number of sympodia per plant, plant height, speed of germination, shoot length, boll weight per plant, vigour index and fibre fineness. In correlation analysis, seed cotton yield was significant and positively correlated with number of bolls per plant followed by boll weight, plant height, seed index and fibre length. Hence, selections based on the above characters will result in genotypes with high seed cotton yield.

Effect of Soil and Foliar Application of Potassium on Pests and Disease Incidence in Bt Cotton in Vertisol

Effect of Soil and Foliar Application of Potassium on Pests and Disease Incidence in Bt Cotton in Vertisol A field study was conducted to evaluate the effect of soil and foliar applied potassium on pest and disease incidence on Bt cotton hybrid MRC-7351 at Main Agricultural Research Station, UAS, Dharwad in Vertisol during 2012-13 and 2013-14. The crop was sown in a randomized complete block design and was replicated thrice. Pooled data of two years indicated that the best results were found when cotton plants were treated with 100:50:75 (RDNP+ 150% RDK) + 2% KNO3 foliar spray at 70, 90 and 110 DAS (T8 ) for higher total number of bolls (46.91), highest seed cotton yield (2689 kg ha- 1 ), lower incidence of pests viz., thrips (2.39 and 1.53 per 3 leaves), jassids (1.68 and 1.57 per 3 leaves), aphids (2.31 and 1.44 per 3 leaves) and shoot weevil (4.19 and 2.60 per 10 plants) populations at 70 and 90 DAS, respectively over rest of the treatments. Significantly lower disease incidence viz., grey mildew (Ramularia areola) (13.89 PDI), leaf rust (14.16 PDI), Alternaria leaf blight (8.05 PDI), Cercospora leaf spot (12.78 PDI) and Rhizactonia wilt (0.72 PDI) were also recorded in the treatment receiving 100:50:75 (RDNP+ 150% RDK) + 2% KNO3 foliar spray at 70, 90 and 110 DAS (T8 ). Thus, it can be concluded that significant reduction in pests population, disease incidence and higher economic yield can be achieved with higher levels of soil applied potassium fertilizers plus foliar spray of KNO3 in Vertisol...

Effect of Different Time of Sowing and Weed Management Methods on Weed Interference, Productivity and Profitability of Bt Cotton in Western Zone of Tamil Nadu

A field experiment was conducted at Tamil Nadu Agricultural University; Coimbatore during winter season of 2015-16 and 2016-17 to evaluates the influence of time of sowing and weed management on weed interference and productivity, profitability of Bt cotton hybrid. Result reveled that, Distinctive time of sowing in cotton impact the weeds and cotton growth. Advance sowing of cotton (1st August) with pre-emergence application of pendimethalin 38.7% CS followed by post-emergence pyrithiobac sodium 5% EC 62.5 g/ha significantly recorded lower total weed density and dry weight and better crop growth, higher seed cotton yield, net return and B: C ratio in both years of the experiment.

Effect of Organic Nutrient Management Practices in Comparison with Conventional Method on Performance of Cotton in Tamil Nadu

A field experiment was conducted in Tamil Nadu Agricultural University farm, Coimbatore to compare the organic nutrient management packages with integrated nutrient management (INM) in cotton. The experiment was consisted of eighteen treatments, laid out in Randomized Complete Block Design and replicated thrice. The results revealed that INM practices increased the plant height over other treatments. Significant increase in yield components like sympodial branches plant-1, number of bolls plant-1 and boll weight were observed under INM treatment and was at par with recommended dose of fertilizers (RDF), Farm yard manure and poultry manure compared to all other treatment combinations. The INM practice resulted in significantly higher seed cotton yield and was comparable with RDF. The quality characters did not exhibit any significant variation among the nutrient management practices. Higher gross and net returns and B:C ratio were also recorded in INM practices.

Effect of tillage and nutrient management on seed cotton yield, yield contributing characters and total uptake by cotton

The field experiment was conducted at the Research farm, Department of Soil Science and Agricultural Chemistry, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola to study the effect of integrated nutrient management on soil quality and cotton productivity under different tillage practices in vertisol. The treatments thus involved two main treatments and eight sub treatments. The experiment main plot comprised of two treatments i.e. conservation tillage (CNS) and CNV. In which one harrowing and two weeding and in conventional tillage (CNV) one ploughing and one harrowing, two hoeing and two hand weeding operations were carried out in eight sub plot treatments of nutrient management. The seed cotton yield was slightly higher under conservation tillage as compared to conventional tillage. Highest seed cotton yield was recorded in the treatment receiving 100 % RDF (60:30:30 NPK kg ha-1 (15.57 q ha-1) followed by 50 % RDF + 50% N (FYM) (14.84 q ha-1).Significantly highest bolls per plant in conservation tillage (19.95 bolls per plant) than in CNV (17.51 bolls per plant) while bolls per plant was recorded in the treatment receiving 100 % RDF (60:30:30 NPK kg ha-1 (20.38 bolls per plant) followed by 50% RDF + 50% N (FYM) (T3) (19.47 bolls per plant).Significantly higher uptake of major and micronutrients was recorded under conservation over conventional tillage. Significantly higher content of macronutrients viz., N, P, K, S and Mg were recorded in the treatment receiving 100 % RDF (60:30:30 NPK kg ha-1) followed by 50 % RDF + 50 % N (FYM). The total uptake of macronutrients at boll development stage was found to be significantly higher in the treatment receiving 100 % RDF (60:30:30 NPK kg ha-1) followed by 50 % RDF + 50 % N (FYM). It was also noticed that the total uptake of nutrients increased from square initiation to boll development stage as the age of the crop advances towards maturity.

Coupling effect of water and nitrogen on mechanically harvested cotton with drip irrigation under plastic film in arid area of western Inner Mongolia, China.

In order to understand the main and interactive effects of water and nitrogen on crop growth and development, yield, fiber quality, and water-nitrogen use efficiency of mechanically harvested cotton with drip irrigation under plastic film in arid area of western Inner Mongolia, a two-factorial experiment with irrigation water amount and nitrogen dosage in completely randomized block design was conducted in Alxa Left Banner of Alxa League in Inner Mongolia. The levels of water irrigation were 216 mm (W1), 288 mm (W2) and 360 mm (W3), and the nitrogen dosages were 127.5 kg·hm-2(N1), 195 kg·hm-2(N2) and 262.5 kg·hm-2(N3). The results showed that water was the decisive factor for cotton growth, and plant height and dry matter accumulation increased rapidly with increasing the water irrigation level, but the ratio of reproductive organs to shoot biomass decreased. Compared with the treatments W1 and W2, the average boll number per plant in W3 was increased by 25.4% and 17.5%, the seed cotton yield was improved by 18.1% and 11.9%, but the single boll mass was decreased by 5.8% and 4.6%, respectively. It indicated that an increase in boll number per plant was the determining factor in achieving high seed cotton yield. Moreover, there was also a significant interactive effect between water and nitrogen affecting the seed cotton yield. Under the condition with low-level irrigation (W1 and W2), the highest seed cotton yield was measured in N1; while for the condition in W3, the seed cotton yield in N2 was greater than that in N1 and N3 by 8.5% and 31.9%, respectively. In general, the regulation of water and nitrogen had no significant effect on fiber quality. Water use efficiencyin W1N1 was 1.37 kg·m-3, which was not significantly different with the value in W3N2, and the nitrogen partial factor productivityin W3N1 was the maximum (51.35 kg·kg-1). Therefore, irrigation had a significant effect on yield increasing, but nitrogen application promoted the seed cotton yield only under well-watered conditions. The treatment with irrigation amount of 360 mm and nitrogen fertilizer of 195 kg·hm-2 could promote the shoot biomass accumulation significantly and achieve the highest seed cotton yield, and its water use efficiency and nitrogen partial factor productivity were 1.37 kg·m-3 and 36.41 kg·kg-1, respectively, indicating the potential of water-saving and yield increasing. Therefore, it was recommended as a suitable water and nitrogen management for the mechanically harvested cotton in arid area of western Inner Mongolia.

Physiological Characters and Seed Cotton Yield of Bt Cotton (interspecific) as Influenced by Crop Geometry and Drip Fertigation

Field experiments were conducted during 2012-2013 and 2013-14 at Tamil Nadu Agricultural University, Coimbatore to study the physiological characters of Bt cotton as influenced by crop geometry and drip fertigation. The experiment was laid out in a strip plot design with replicated thrice. The treatments in main plot consisted of four crop geometry levels (120 x 60 cm, 120 x 90 cm, 150 x 60 cm and 150 x 90 cm) and sub plots consisted of four nutrient levels viz., 75, 100 and 125 % of recommended dose as water soluble fertilizer (WSF) through drip system and conventional practice of irrigation and fertilizer application. Here, 75 % of the P as basal (single super phosphate) and remaining 25 % P as water soluble fertilizer and the entire quantity of N and K as water soluble fertilizer was applied based on recommended fertigation schedule. The experimental results revealed that crop growth rate was significantly higher under 120 x 60 cm and was comparable with crop geometry of 120 x 90 cm with application of 125 % of recommended dose as water soluble fertilizer over wider crop geometry level of 150 x 90 cm compared to conventional method of irrigation and fertilizer application. Higher seed cotton yield was recorded with crop geometry of 120 x 90 cm with 125 % as water soluble fertilizer over conventional method of cultivation.

Comparative response of Bt cotton to water under drip and check-basin methods of irrigation in semi-arid conditions of Punjab

Field experiments were conducted for two years to investigate the effect of various methods of planting and irrigation water levels on yield and water use efficiency in cotton irrigated through surface drip irrigation in semi-arid region of Punjab. The treatments comprised three methods of planting under drip irrigation (lateral in each row, lateral in between pair of rows and lateral in between pair of rows but third row missing) and one check-basin method of irrigation at three levels of irrigation (0.6, 0.8 and 1.0 Etc). The pooled results revealed that drip lateral along each row, irrespective of irrigation water levels, produced significantly higher (20.2%) seed cotton yield as compared with check basin method. The increase in irrigation water level, irrespective of methods of irrigation, failed to cause any significant effect on seed cotton yield but stick yield increased significantly with increase in quantity of irrigation water. Drip irrigation with laterals along each row, irrespective of levels of irrigation water, resulted in significant increase (49%) in water use efficiency as compared to check basin method of irrigation. Water use efficiency, irrespective of method of planting, spectaculary decreased with increase in irrigation water. The results of the present study revealed that drip irrigation with lateral along each row at the lowest level of water (0.6 Etc) resulted in highest water use efficiency (22.0 kg/ha/mm) accompanied by 25% higher seed cotton yield and 18% of saving in irrigation water as compared with check basin method of irrigation.

Assessment of yield and yield related traits to determine earliness in Egyptian cotton (Gossypium barbadense, L).

A field experiment was conducted to identify elite early maturing G. barbadense genotypes by evaluating morphological and fibre quality traits advanced genotypes developed at CICR, Regional Station, Coimbatore. Ten advanced genotypes of G. barbadense genotypes viz ., CCB-5, CCB-11, CCB-17, CCB-26, CCB-27, CCB-28, CCB-29, CCB-30, CCB-33 and CCB-36 were used in this study. In the present study, analysis of variance of genotypes was highly significant for all the traits studied. Three genotypes viz ,. CCB-29, CCB-36 and CCB-5 were found to be early maturing in terms of days to first flower, lower node no to first sympodial branch, boll formation in 90, 120 and 150 days after sowing and opening of bolls in 120 and 150 days after sowing. Regarding yield traits, maximum number of bolls per plant and higher seed cotton yield were recorded in the genotypes CCB-29, CCB-36 and CCB-5. It was also observed that maximum staple length, strength and desirable micronaire were registered in CCB-29, CCB-36, CCB-5 and CCB-11. The correlation coefficients showed that the days taken to first flower, number of nodes in lower first sympodial branch, bolls formed at 150 days, number of bolls per plant have significant positive correlations with seed cotton yield. The positive correlations of yield components with seed cotton yield are reliable and more effective and efficient indicators for selecting early maturing genotypes in Egyptian cotton.

Response of Cotton to Potassium Levels Under Water Regime

A field trial was conducted at Experimental Field of Field Crop Department of College of Agriculture-Abu-Graib during 2011 and 2012 seasons to investigate the effect of potassium level in growth, lint yield and its components of cotton (Gossypium hirsutum L.) cultivar Lashata was grown under abundance and deficit water conditions. Split plot arrangement with randomized complete block design was used with three replicates. Irrigation intervals occupied main plots (Irrigation weekly and each two weeks) while potassium levels (0, 220, 280, 340, 400 kg k2O5/ha) occupied subplots. The statistical analysis showed superiority of irrigation at two weeks of seed cotton yield (3.75 t/h), number of open bolls per plant (20.47), number of sympodium per plant (19.65 and 17.27), ginning percentage (37.47) and water use efficiency (0.38 kg/m3). There were significant effect of potassium in traits. The level 340 kg K2O5/ha was gave the highest seed cotton yield (3.87 t/ha) due to attained the highest number of open bolls (29.25 bolls per plant for first season and gave 3.71 t/ha at 280 kg K2O5/ha due to higher boll weight (3.57 g) for second season. It could be conclude irrigation at two weeks with apply 280 kg K2O5/ha hadk attained the highest seed cotton and ginning percentage to reduce water requirements of cotton in central region of Iraq.

Effect of different herbicides on growth and yield attributes and seed cotton yield inhirsutumcotton

A field experiment was conducted during kharif seasons of 2012 and 2014 at C. S. Azad University of Agriculture & Technology, Kanpur to study the effect of different uses of herbicides on growth and yield attributes and seed cotton yield in hirsutum cotton. Data indicated that application of pendimethalin @ 1 kg a. i./ha as PE+quizalofopethyl @ 50 g a. i./ha 30 DAS+one hoeing 50 DAS and weed free plot improved significantly all the growth and yield attributing characters over weedy check. Weed free check plot produced significantly highest seed cotton yield (1311 kg/ha) and lint yield (442 kg/ha) than weedy check. Herbicidal application of pendimethalin @ 1 kg a. i./ha as PE+Quizalofopethyl @ 50 g a. i./ha 30 DAS+one hoeing 50 DAS was found next best treatment of producing significantly higher seed cotton yield (1157 kg/ha) and lint yield (357 kg/ha) than weedy check (514 kg/ha) and (174 kg/ha) seed cotton yield and lint yield, respectively. Lowest dry weight (3.98 g/m2) of weeds was recorded with direct spray of glyphosate 45% SL @ 1 kg a. i./ha. Higher weed control efficiency (83.3%) was recorded with direct spray of glyphosate 45% SL @ 1 kg a. i./ha followed by pendimethalin @ 1 kg a. i./ha as PE+quizalofopethyl @ 50 g a. i./ha 30 DAS+one hoeing 50 DAS (63.5%). Highest net returns (Rs. 19824/ha) and B: C ratio (1.56) were obtained with herbicidal application of pendimethalin @ 1 kg a. i./ha as PE+quizalofopethyl @ 50 g a. i./ha 30 DAS+one hoeing 50 DAS.

Influence of Integrated Nutrient Management on Growth and Yield of Bt Cotton (Gossypium hirsutumL.) Hnder Dry Farming Condition

The field experiment was conducted during kharif seasons of 2008–2013 on medium black soil at Dry Farming Research Station, Junagadh Agricultural University; Targhadia to study the effect of integrated nutrient management (INM) techniques on seed cotton yield, economics and soil physico-chemical properties under dry farming condition. The experiment was laid out in randomized block design with ten different treatment combinations comprising of organic and inorganic fertilizers (NPK), gypsum, castor cake, compost and vermi-compost replicated in a thrice. The experimental result showed that the significantly higher seed cotton yield (2298 kg/ha) and highest net return (98289/ha) were recorded under treatment T9 (80 kg/ha + 10 tones compost/ha + 500 kg castor cake/ha + bio-fertilizer-Azotobacter + PSM). The highest number of branches/plant, numbers of balls/plant and plant height (cm) were also recorded under treatment T9.

Yield of cotton cultivars under different irrigation depths in the Brazilian semi-arid region

<title>ABSTRACT</title><p>The objective of this study was to evaluate the effect of irrigation depths on seed cotton yield and water-use efficiency of cotton cultivars in the Brazilian semi-arid region. Field experiment was conducted during two consecutive years in the Apodi region, RN, using sprinkler irrigation. The experiment consisted of factorial combination in split-plots, composed of four irrigation depths (130; 100; 70 and 40% ETc and four cotton cultivars - FiberMax 993, BRS 286, BRS 336 and BRS 335), in randomized block design with 4 replicates. Data were evaluated by mean test (Tukey) and regression analysis. Considering the irrigation depths of 40% ETc, cotton yield was 48% lower compared to the higher irrigation depth (130% ETc). The higher water-use efficiency (0.69 kg m<sup>-3</sup>) was obtained with 70% ETc irrigation depth. The highest seed cotton yield was achieved with the higher water depth for all evaluated cultivars. Yield response factor (Ky) was equal to 0.632, 0.711, 0.784 and 0.858, for FiberMax 993, BRS 286, BRS 335 and BRS 336 cultivars, respectively. FiberMax 993 and BRS 286 cultivars presented the best performance, showing that they are more suitable for irrigated farming in the semi-arid region.</p>

Bioefficacy of new chemistry molecules against sucking pests of Bt transgenic cotton

Studies were conducted to evaluate some new chemistry insecticide molecules as foliar application for their bioefficacy against major sucking pests and toxicity against predators of Bt transgenic cotton at Department of Entomology, Dr. Panjabrao Deshmukh Krishi Vidyapeth, Akola during 2013-2014 with eight treatment and three replications. After third spray the application of flonicamid 50 WG@ 0.02 per cent, dinotefuran 20 SG @ 0.008 per cent and imidacloprid 30.5 SC @ 0.005 per cent proved effective in recording minimum aphid population i.e. 1.27, 1.37 and 1.92 aphids per leaf, respectively. The treatment with dinotefuran 20 SG @ 0.008 per cent and 0.006 per cent, fipronil 5 SC @ 0.015 per cent, acetamiprid 20 SP @ 0.004 per cent and flonicamid 50 WG @ 0.02 per cent successfully checked the incidence of leafhopper with in the range of 0.63 to 0.93 leafhoppers/leaf at third spray. The application of fipronil 5 SC @ 0.015 per cent, flonicamid 50 WG @ 0.02 per cent, imidacloprid 30.5 SC @ 0.005 per cent, dinotefuran 20 SG @ 0.008 per cent and acetamiprid 20 SP @ 0.004 per cent effectively minimized the incidence of thrips population with in the range of 2.59 to 3.60 thrips per leaf at the end of third spray. Whereas, acetamiprid 20 SP @ 0.004 per cent proved effective in lowering down the whitefly population (0.99 whiteflies/leaf), which was closely followed by flonicamid 50 WG @ 0.02 per cent (1.10 whiteflies/leaf), fipronil 5SC @ 0.015 per cent (1.11 whiteflies/leaf), dinotefuran 20 SG @ 0.008 per cent (1.20 whiteflies/leaf), and imidacloprid 30.5 SC @ 0.005 per cent (1.34 whiteflies/leaf). However, during the present studies no deleterious effect of insecticidal treatments were observed on population of natural enemies. The highest seed cotton yield was recorded in the plot sprayed with fipronil0.015 per cent, which was closely followed by dinotefuran 0.008 per cent, flonicamid 0.02 per cent, imidacloprid 0.005 per cent, acetamiprid 0.004 per cent and dinotefuran 0.006 per cent. On the basis of economics, imidacloprid 0.005 per cent proved to be the most economically viable treatment followed by acetamiprid 0.004 per cent, fipronil 0.015 per cent, dinotefuran 0.006 per cent and flonicamid 0.02 per cent. The present findings indicates that these insecticides can be suitably incorporated in an integrated management programme of sucking pests of cotton.

Effects of foliar application of nutrients on growth and yield of Bt cotton (Gossypium hirsutum L.)

Field experiments were conducted for three years during Kharif 2009-2011 to study the effect of foliar application of nutrients (N, Mg, Fe, Zn, Mn and B) on growth and yield parameters of Bt cotton. Pooled data indicated highest seed cotton yield (3421.4 kg/ha) with application of MgSO4 1.0%+ ZnSO4 0.5%. Better net returns ( 100760/ha) and improved B:C (4.06) ratio for MgSO4 1.0% + ZnSO4 0.5% clearly supported its application benefits to realize higher yield . DOI: http://dx.doi.org/10.3329/bjb.v44i1.22717 Bangladesh J. Bot. 44(1): 9-14, 2015 (March)

Growth, seed cotton yield and yield attributes of American cotton (Gossypium hirsutum L.) hybrids under different spacing and nitrogen levels

Field studies were conducted at Punjab Agricultural University, Regional Station, Faridkot during Kharif 2013 to evaluate the performance of two hirsutum hybrids (FHH200 and LHH144) in main, two spacing levels (67.5×75 cm and 67.5×90 cm) in sub and three nitrogen levels (i.e. 112,150 and 187 kg N/ha) in sub plots of Split Plot Design replicated thrice. FHH200 recorded significantly highest seed cotton yield (SCY) of 2953.1 kg/ha followed by LHH144 (2495.2 kg/ha), while among spacing levels differences were non-significant. Among tested N levels, 150 kg N resulted in highest SCY (2868.1 kg/ha) followed by 187kg N (2738.1 kg/ha) while statistically least SCY was recorded with 112 kg N (2566.3 kg/ha). Though cost of cultivation increased with each increase of nutrient levels, but gross as well as net returns improved significantly only up to 100 per cent RD and declined thereafter. B:C ratio was significantly higher under 150kg N/ha (2.34) as compared to 187 kgN/ha (2.15). Farmers should opt for FHH200 and a spacing level of 67.5×75cm for hirsutum hybrids and must apply N @150kg/ha to realize higher SCY and consequently remunerative returns.

Effect of Water Stress on the Growth and Yield of Cotton Crop (<i>Gossypium hirsutum</i> L.)

Cotton is one of the most important fibre crops playing a key role in economic and social affairs of the world. Water is a critical factor which influences on growth and yield of the cotton crop. Scarcity of water has put tremendous pressure on scientists to introduce drought tolerant cotton varieties. This study was aimed to determine water stress effects on the growth and yield of cotton. The present study was carried out to examine the effect of number of irrigations on the growth and yield of cotton during 2014. The field trial was conducted at the Experimental Fields of Agronomy Section, Agriculture Research Institute, Tandojam, Pakistan. A three replicated Randomized Complete Block Design (RCBD) was employed to layout the experiment having plot size of 2.5 m × 5 m (12.5 m2). Four cotton varieties i.e. NIAB-78, Shahbaz-95, Sindh-1 and TH-224/87 were chosen for this study based on their frequent farmer usage. All the agronomic practices were performed according to standard procedures. Results showed that all the growth and yield components of cotton were significantly (P 0.05) affected by irrigation frequencies. The cotton crop irrigated six times at 21 days interval showed better results with 138.16 cm plant height, 1.45 monopodial branches per plant, 21.83 sympodial branches per plant, 44.58 bolls per plant, 33.86% G.O.T., and 26.97 mm staple length, 149.84 g seed cotton yield per plant and 2271.16 kg·ha-1 seed cotton yield. This study concluded that variety NIAB-78 showed superiority over Shahbaz-95, Sindh-1 and TH-224/87 in almost all the characters of economic importance, and the cotton crop received 6 irrigations at 21 days interval resulted in significantly economical overall performance as compared with 5 irrigations or 4 irrigations with higher seed cotton yield.