non-Bt Cotton Research Articles

EFFECT OF SAW GINNING ON THE FIBRE QUALITY OF Bt AND NON-Bt COTTON

Bt cotton refers to a plant which has Bacillus thuringiensis (Bt) toxins in many of its cells. This naturally occurring soil bacterium will be used to reduce insect damage from bollworm, pink bollworm, and budworm. Therefore, farmers who are cultivating the Bt cotton variety will not be subjected to spray pesticides to control these worms. Whereas in this study, the non-Bt cotton (DP-90) refers to the commercially known variety which have no Bacillus thuringiensis (Bt) toxins in its cells. During the cultivation of non-Bt cotton varieties, the control of bollworms is done through the application of pesticides, which is a costly exercise in terms of cost of pesticides, spray equipment and labour. Along with the cost of cultivation, the best index to cotton quality is the performance of the fibres during spinning at the textile mill. In the present study the effect of saw ginning to the quality of both varieties was studied. The result could help the spinners to predict the preperformance of both varieties when subjected to the mechanical action of modern high rotating spinning machines parts. Ginning results a significant effect (at 0.05 level of significance) in all other measured fibre quality properties (upper half mean length, length uniformity index, short fibre content by number and by weight, level of neps, single fibre tenacity and elongation) of both Bt and non-Bt (DP-90) cotton varieties. The impact of ginning on the studied fibre quality properties was relatively severer on Bt cotton varieties than non-Bt (DP-90) varieties.

Response of foliage- and ground-dwelling arthropods to insecticide application: Early step for cotton IPM in the Brazilian semiarid

Foliage- and ground-dwelling arthropods provide ecosystem services, including decomposition and biological control of agricultural pests. Despite this, there is little information on the ground-dwelling arthropod community associated with cotton crops and about their role under pest control practices. Identifying these communities and their preservation would assist smallholder cotton growers in considering an Integrated Pest Management (IPM) approach to pest control. In this context, the strategy of using selective- or broad-spectrum insecticides (both applied only once the pests reached an economic threshold) was assessed using field plots set up within non-Bt cotton structured refuge of a grower field measuring the response of both foliage- and ground-dwelling arthropods and yield. The abundance, species richness, dominance indices, and foliage-dwelling predators and pest species and ground-dwelling predators and decomposers were compared between untreated and insecticide treatments, as was the crop yield. In response to pest monitoring, insecticides were applied 5 and 3 times during the 2018 and 2020 growing seasons, respectively. In 2018 and 2020, 16 and 12 foliage-dwelling predator arthropods and 43 and 47 ground-dwelling predator and decomposer arthropods were collected, respectively. During the 2018 season, broad-spectrum insecticide applications reduced the abundance of foliage-dwelling predators, but had no significant impact on the ground-dwelling community. Principal response curves (PRC) indicated a negative impact of broad-spectrum insecticides only on the foliage-dwelling community, particularly among the Formicidae and Araneae species. Insecticide applications in the 2020 season were only required at the end of the crop season and did not significantly influence the foliage- or ground-dwelling communities. The selective insecticide regime yielded as well as the broad-spectrum insecticide regimes higher yielded than untreated plots. These results demonstrated to the small landholders engaging conservation biological control for the first time, the advantages of an IPM approach to pest management.

Prey-mediated effects of mCry51Aa2-producing cotton on the predatory nontarget bug Orius majusculus (Reuter).

Genetically engineered (GE) cotton, MON88702, is protected against certain sucking pests, such as plant bugs and thrips, by producing mCry51Aa2, a modified protein from Bacillus thuringiensis (Bt). Predatory pirate bugs (Orius spp.), natural enemies contributing to biological pest control, are also sensitive to the insecticidal protein when exposed continuously to high concentrations. We evaluated effects of MON88702 on Orius majusculus when fed prey types with different mCry51Aa2 concentrations. When neonates were provided exclusively Tetranychus urticae spider mites reared on MON88702 (high mCry51Aa2 content), adverse effects on predator survival and development were confirmed, compared with specimens fed prey from near-isogenic non-Bt cotton. When fed a mixture of T. urticae and Ephestia kuehniella eggs (mCry51Aa2-free), predator life table parameters were similar to the treatment where eggs were fed exclusively. When mCry51Aa2-containing spider mites were provided for a limited time at the beginning or the end of juvenile development, effects were less pronounced. While pirate bug nymphs showed similar consumption rates for prey from Bt and non-Bt cotton, choice experiments revealed a preference for E. kuehniella eggs over spider mites. Lepidopteran larvae (Spodoptera littoralis, high mCry51Aa2 content) or cotton aphids (Aphis gossypii, mCry51Aa2-free) reared on MON88702 as alternative prey did not result in adverse effects on O. majusculus. Our study suggests limited risk of mCry51Aa2-producing cotton for O. majusculus, because its sensitivity for the Bt protein is relatively low and its natural food consists of diverse prey species with varying concentrations of Bt protein.

Retraction: The influence of transgenic (Bt) and non-transgenic (non-Bt) cotton mulches on weed dynamics, soil properties and productivity of different winter crops.

Retraction: The influence of transgenic (Bt) and non-transgenic (non-Bt) cotton mulches on weed dynamics, soil properties and productivity of different winter crops.

Determination of Silicon Accumulation in Non-Bt Cotton (Gossypium hirsutum) Plants and Its Impact on Fecundity and Biology of Whitefly (Bemisia tabaci) under Controlled Conditions

Considering the resistance development-potential of whitefly (Bemisia tabaci) against control tactics with limited action mechanisms, the present study investigated the accumulation of two different silicon (Si) sources (SiO2 and K2SiO3) in cotton plants. The tested dose rates (0, 200, and 400 mg/L) of both Si sources were applied directly to the soil or through foliar application on cotton leaves. Moreover, a laboratory bioassay was also conducted to evaluate the performance of applied Si sources against the oviposition preference and biology of B. tabaci. A significantly higher Si accumulation, reduction in oviposition preference, and prolonged developmental period of all nymphs and total life cycle of B. tabaci was observed in the case of foliar-applied silicon. Similarly, among Si sources, a significant decline in the number of oviposited eggs and delay in the developmental period of B. tabaci was observed in the case of SiO2, followed by K2SiO3. Moreover, cotton plants subjected to SiO2 treatments possessed higher Si contents in their leaves than K2SiO3 treated plants. The results further revealed that both Si sources showed promising results at their higher concentrations regarding the tested parameters of Si accumulation, fecundity, and developmental period of B. tabaci. Our results strongly suggest that among emerging pest control strategies in cotton plants lies the use of foliar application of Si, which can also be incorporated in different integrated pest management programs due to its safety for humans and beneficial insect fauna.

Incidence of Mirid Bug Species Complex in Bt and Non-Bt Cotton Genotypes

The present study on the incidence of mirid bugs in relation to weather factors in Bt and non Bt cotton hybrids was carried out at the KVK, Haradanahalli, Chamarajanagar. During the study three species of mirid bugs viz., Creontiades biseratense (Distant), Helopeltis theivora (Waterhouse) and Taylorilygus apicalis (Fiber) were observed, of which C. biseratense was the dominant. Maximum incidence of C. biseratense (6.56/ 10 squares/ plant), Helopeltis theivora (3.60/ 10 squares/plant) and Taylorilygus apicalis (2.40/ 10 squares/ plant) was observed at 42nd, 45th, 43rd standard meteorological weeks. Correlation coefficients revealed that maximum temperature has a significant negative association with incidence. However, non-significant negative association was exhibited by evening relative humidity (RH) and rainfall. In contrast to this, significant positive association was observed with morning RH, a non-significant positive one with minimum temperature.

EVALUATION OF TRANSGENIC COTTON CULTIVARS CONTAINING CRY TOXINS FROM BACILLUS THURINGIENSIS AGAINST THRIPS

Cotton (Gossypium hirsutum L.) is a significant fiber crop that is contributing 7 to 10% in the GDP of Pakistan. In the production of cotton, Pakistan is ranked at 4th position among the major cotton growing countries. Various insect pests, especially sucking and chewing pests, attack cotton crop. Among the sucking pests, thrips (Thrips tabaci Lindeman) causes the most significant damage to cotton at seedling stage. Due to tremendous usage of insecticides, these pests have developed resistance against insecticides. Therefore, cultivation of resistant cotton varieties is the best tactic that can minimize the attack of thrips on this crop. In the present study, five Bt cotton varieties with different cry toxins were evaluated for their resistance/susceptible response to thrips. The cotton cultivars selected for this study were including four Bt cotton cultivars (two single and two double toxins) and one non-Bt cotton cultivar. The experiment was carried out under climatic conditions of Faisalabad, Pakistan. There was not any pronounced difference in thrips population on different Bt cotton cultivars either they were single or dual toxin gene cotton cultivars. MNH-186 and FH-141 showed decreasing trend in population of thrips with the passage of time as compared to other Bt cotton cultivars. The little variation in thrips population among the Bt cotton cultivars showed that all Bt cotton varieties had good control effect on the thrips population. Thrips population was insignificant with respect to leaf position i.e. upper, middle and lower leaves. Correlation study of thrips population with different environmental factors exhibited r values of -0.2213, 0.49837 and 0.41735 for temperature, humidity and rain fall, respectively.

Population Dynamics of Aphid, Aphis gossypii Glover on Bt and non-Bt Cotton and Correlation with weather Parameters

Investigations on the population dynamics of aphid Aphis gossypii Glover on Bt (G.Cot.Hy.8 BG II) and non-Bt (G.Cot.Hy.8) were carried out at Main Cotton Research Station, Navsari Agricultural University, Surat, Gujarat during the Kharif, 2020-21. The incidence of aphids initiated in the first week of July (27th SW) in Bt cotton hybrid and in the second week of July (28th SW) in non-Bt cotton hybrid and continued till the crop harvest in the second week of January (2nd SW) in both the hybrids. The peak activity of aphids was recorded during the third week of December (51st SW) in Bt as well as non-Bt cotton hybrid. In both Bt and non-Bt cotton, the aphid population had a significant negative correlation with morning relative humidity. There was a highly significant negative correlation with minimum temperature, evening relative humidity, rainfall, rainy days, and a positive correlation with sunshine hours.

Antimicrobial Efficacy of Gossypium hirsutum L. (Bt and Non-Bt) Phytochemical Extracts: The Most Widely Cultivated Species of Cotton in the World

The phytochemical analysis of Gossypium hirsutum was carried out using standardized methods for the evaluation of active compounds and provided opportunities for use in the preparation of new drugs. Bacillus thuringiensis (Bt) and non-Bacillus thuringiensis (non-Bt) cotton species are picked for the current study and during this, different solvents such as acetone, ethanol, methanol, pet-ether, chloroform, water used for phytochemical and antimicrobial screening from cotton leaves and seeds in the year 2013. The phytochemical analysis found the presence and absence of flavonoids, phenols, glycosides, saponins, amino acids and tannins, alkaloids, anthraquinones, steroids, terpenoids, sugars respectively. The investigation on the antibacterial efficacy against pathogenic strains of bacteria has been conducted and the highest inhibitory effect is present in leaf chloroform extract of non-Bt cotton against Pseudomonas fluorescens, whereas leaf methanol extract of Bt cotton was found to be most potent against Escherichia coli. Ethyl acetate and chloroform extracts have been effective against the remaining bacterial strains. Water extracts have a great inhibiting effect on all fungal pathogens tested. Results suggest that some samples may contain various pharmacologically active compounds with moderate antimicrobial properties.

Sowing Date influences cotton leaf curl disease (CLCuD) incidence and productivity of non-Bt cotton cultivars

Sowing Date influences cotton leaf curl disease (CLCuD) incidence and productivity of non-Bt cotton cultivars

Sowing Date influences cotton leaf curl disease (CLCuD) incidence and productivity of non-Bt cotton cultivars

Sowing Date influences cotton leaf curl disease (CLCuD) incidence and productivity of non-Bt cotton cultivars

Drop-off behaviour of Bt-resistant and Bt-susceptible Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larvae on Bt-cotton and non-Bt cotton plants.

The highest natural mortality rate of larval Lepidoptera in field populations occurs in the first instar, but it is highly variable. The pattern and degree of survival is not easily predicted but depends on their ability to establish on host plants. Lepidopteran larval dispersal behaviour, known as 'drop-off', happens when the host is unsuitable for larvae to settle and begin feeding. Understanding drop-off behaviour of Helicoverpa armigera (Hübner) with and without physiological resistance to Bt toxins on Bt and non-Bt cotton plants is an important component for resistance management strategies for this insect. We examined the drop-off behaviour of H. armigera to determine: (1) whether they move the same way or differently in response to Bt and non-Bt, and (2) could H. armigera larvae detect Bt toxin levels in cotton plants or did they move independently of toxin levels? In this study, we assessed the drop-off behaviour of Bt-resistant and Bt-susceptible H. armigera neonates on artificial diets and cotton plants with and without Bt toxin during the first 12 h after hatching. Bt-resistant and Bt-susceptible H. armigera neonates behaved differently on Bt and non-Bt substrates. The percentages of Bt-resistant larvae that dropped off Bt and non-Bt cotton plants were not significantly different. In contrast, significantly more Bt-susceptible larvae dropped off Bt cotton than non-Bt cotton plants over time. Although Bt-susceptible larvae could not detect Bt toxin, they showed preference on non-Bt toxin substrates and were more likely to drop off substrates with Bt toxin.

Estimation of Combining Ability Influence on F1 Generation for Various Quantitative and Qualitative Traits in BT and Non-BT Cotton Gossypium hirsutum L.

General and specific combining ability is one of the important plant breeding tools used for best selection of F1 group based on the growth and yield contributing factors. This experiment was carried out during 2014 under agro-ecological condition of Tandojam, Sindh Pakistan. In this study three lines of Bt-008, IR-1525 and neelam-131 as female parents and three testers such as NIA Sadori, NIA Ufaq and NIA Perkh as male parents were investigated based on randomized complete block design which were replicated thrice. In F1 generation, the mean squares for combining ability for target characteristics displayed highly significant GCA effects in lines for all traits except lint index. But in case of testers, the GCA effects were significant for sympodial branches plant-1, seed index and seedcotton yield plant-1 and highly significant only for monopodial branches plant-1, GOT%, staple length. While, mean squares values for the interaction of line x tester revealed highly significant SCA effects for plant height, monopodial branches plant-1, boll weight and GOT%. The two parents Neelam-131 and NIA Ufaq manifested higher general combining ability effects and were good general combiners for yield and yield components and can make a potential material for varietal seed development. For yield contributing characters, crosses IR-1525 x NIA Ufaq and IR-1525 x Perkh showed significant SCA effects among the rest of crosses. Consequently, it is advised that those crosses to be selected having high SCA with better GCA for refining a specific trait.

Assessing fitness costs of the resistance of Spodoptera frugiperda (Lepidoptera: Noctuidae) to pyramided Cry1 and Cry2 insecticidal proteins on different host plants

Fall armyworm (FAW), Spodoptera frugiperda (Smith), is one of the major pests targeted by transgenic crops expressing insecticidal proteins from Bacillus thuringiensis (Bt) Berliner. However, FAW presents a high capacity to develop resistance to Bt protein-expressing crop lines, as reported in Brazil, Argentina, Puerto Rico and the southeastern U.S. Here, FAW genotypes resistant to pyramided maize events expressing Cry1F/Cry1A.105/Cry2Ab2 (P-R genotype) and Cry1A.105/Cry2Ab2 (Y-R genotype) from Brazil were used to investigate the interactions between non-Bt hosts (non-Bt maize, non-Bt cotton, millet and sorghum) and fitness costs. We also tested a FAW genotype susceptible to Bt maize and F1 hybrids of the resistant and susceptible genotypes (heterozygotes). Recessive fitness costs (i.e., costs affecting the resistant insects) were observed for pupal and neonate to adult survival of the P-R genotype on non-Bt cotton; larval developmental time of the P-R genotype on millet and sorghum; larval and neonate-to-adult developmental time of the Y-R genotype on non-Bt cotton and sorghum; the fecundity of the Y-R genotype on non-Bt cotton; and mean generation time of both resistant genotypes. However, on non-Bt cotton and non-Bt maize, the P-R genotype had a higher fitness (i.e., fitness benefits), displaying greater fecundity and rates of population increases than the Sus genotype. Non-recessive fitness costs (i.e., costs affecting heterozygotes) were found for fecundity and population increases on millet and sorghum. These findings suggest that, regardless of the disadvantages of the resistant genotypes in some hosts, the resistance of FAW to Cry1 and Cry2 Bt proteins is not linked with substantial fitness costs, and may persist in field conditions once present.

Mobility of N, P and K and root growth of Bt and nonBt cotton in clayey soil under different NPK levels

The mobility of applied nutrients in soil and root growth determines the interception and uptake of nutrients by crop. Present investigation includes two pot culture experiments under glass house condition. The objective of first experiment was to study the mobility of N, P and K in soil profile of cotton in respect to different NPK levels; whereas, in second experiment root growth of Bt and non-Bt cotton hybrids were studied under different NPK levels. The first experiment comprised of four NPK levels, i.e. control- 00:00:00, 50:25:25, 62.5:31.25:31.25 and 75:37.5:37.5 kg N, P2 O5 , K2 O ha-1 and four depth of sampling, i.e. 15, 30, 45 and 60 cm in soil column. Whereas, in second experiment Bt and non-Bt counterpart of same cotton hybrid were evaluated for root growth under above mention NPK levels. Both the experiments consist of four set of replications and experimental design was FRBD. Results illustrate that, concentration of available N, P and K in soil profile of cotton significantly increased with the highest rate of NPK than control. Irrespective of NPK levels, shallow depth of sampling (15 cm) recorded maximum concentration of available N, P and K throughout the period of experimentation. However, N was mobile up to 60 cm depth and K up to 45 cm depth in 90 days; whereas P mobility was restricted only up to 15 cm depth even in 90 days. Each increase in NPK level increased the downward mobility of N in soil by 15 cm at 30 days after fertilizer application. The increased in available P content with increase in NPK levels remains restricted to placement zone (15 cm) only and its downward mobility in soil profile over the period in response to NPK levels was absent. However, K was found mobile up to 45 cm depth under highest level of NPK at 30 days after fertilizer application. As regards root growth, Bt hybrid recorded longest root at initial stage whereas, at later stage it was in non-Bt. Application of the highest rate of NPK significantly increased root length over lower levels.

Effects of Grazing Dairy Cows on Bt and Non-Bt Cotton Crop Residues on the Ratios of each Ruminal Acetate and Propionate to Milk Palmitic Acid and the Correlation of both Ratios to Acetate to Propionate in Gezira State, Sudan

Effects of Grazing Dairy Cows on Bt and Non-Bt Cotton Crop Residues on the Ratios of each Ruminal Acetate and Propionate to Milk Palmitic Acid and the Correlation of both Ratios to Acetate to Propionate in Gezira State, Sudan

Effects of Grazing Dairy Cows on Bt and Non-Bt Cotton Crop Residues on the relationship between Rumen Total Bacterial Count and the proportion of Oleic acid in milk in Gezira State, Sudan

Effects of Grazing Dairy Cows on Bt and Non-Bt Cotton Crop Residues on the relationship between Rumen Total Bacterial Count and the proportion of Oleic acid in milk in Gezira State, Sudan

Effect of host plants on the oviposition preference of pink bollworm, Pectinophora gossypiella (Lepidoptera: Gelechiidae)

Abstract Pink bollworm (Pectinophora gossypiella (Saunders, 1843)) (Lepidoptera: Gelechiidae) is an important pest of cotton. We aimed to study the effect of different host plants on the oviposition preference of pink bollworm under laboratory conditions. Cotton (Bt and non-Bt), okra and hibiscus plants were used, which vary in morphological characteristics. Significant differences were observed in the density of trichomes and it is positively correlated with oviposition behaviour of pink bollworm. In a no-choice test, we recorded a higher number of eggs on Bt and non-Bt cotton plants. In two-, three- and four-choice experiments, pink bollworm preferred to deposit the maximum number of eggs on non-Bt cotton among other host plants. A substantially higher number of eggs were laid on Bt cotton in combinations with okra and hibiscus and a considerably lower number on non-Bt cotton. We recorded fewer numbers of eggs on hibiscus in all combinations. Overall, pink bollworm moths showed greater affinity towards non-Bt cotton plants and deposited the maximum number of eggs there. From the practical point of view, the development of cotton genotypes which are devoid or have a lesser density of trichomes may be a possible solution to reduce the pink bollworm egg load on cotton.

Feeding Behavior and Fruiting Form Damage by Bollworm (Lepidoptera: Noctuidae) in Bt Cotton.

Bt technologies have played a major role in the control of bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), in cotton. Variation in expression levels among varieties and plant parts, along with selection pressure on bollworm populations, has led to the development of resistance to some Bt proteins. Trials were conducted to evaluate how cotton varieties expressing different Bt proteins affect bollworm larval behavior and their damage in flowering cotton. Differences in larval recovery were observed among cotton varieties at 3 d with 3-gene Bt cotton having the lowest recovery and non-Bt cotton having the greatest recovery. Loss of bloom tags and abscission of small bolls at the site of infestation affected bollworm larval recovery among varieties. Day after infestation was the main factor that affected bollworm movement across all varieties. Number of total damaged fruiting forms by an individual bollworm larva was different among all varieties. Overall, flower bud (square) and fruit (boll) damage by an individual larva was lower on 3-gene cotton than 2-gene cotton and non-Bt cotton. An individual larva damaged fewer squares on 2-gene cotton than non-Bt cotton, but boll damage from bollworm was similar among 2-gene cotton and non-Bt cotton. The level of square and boll damage in 2-gene cotton has increased compared to previous research further supporting the occurrence of bollworm resistance to Cry proteins. The 3-gene cotton containing the Vip3A gene experienced low levels of damage and survival. These results will be important for improving management recommendations of bollworm in Bt cotton technologies.

English

Whitefly is a serious threat to the cotton production. To find out the most suitable control measure a field experiment was conducted at District Layyah, to compare the efficacy of different pre-tank mix insecticides., viz. Legand (spiromesifen + abamectin), Actify (Isoprocarb + etiprole), Bila (Pyriproxyfen + acetamaprid), Best Guard (buprofezin + nitenpyram), Jeera (Pyriproxyfen + acetamaprid), Rugra (nitenpyram + chlorfenapyr), Editor (acetamaprid + ibiocydam), and Concept Plus (acephate + phenoxaprop) on BT-886 and Non-BT (Shahkar) cotton varieties. Maximum population reduction of adult whitefly after first application of insecticides was found in Legand on BT and Non-BT cotton crop exhibited, 24.37 and 37.66 after 2 days, 53.08 and 55.31 after 4 days and 73.29 and 68.17 after 6 days respectively. Maximum population reduction of nymph whitefly was found in Legand on BT and Non-BT cotton crop exhibited 33.85 and 34.07 after 2 days, 55.10 and 54.49 after 4 days and 74.66 and 75.28 after 6 days respectively. Maximum population reduction of adult whitefly after second application of insecticides was found in Legand on BT and Non-BT cotton crop exhibited, 24.56 and 39.57 after 2 days, 30.29 and 55.97 after 4 days and 71.34 and 69.62 4after 6 days respectively. Maximum population reduction of nymph whitefly was found in Legand on BT and Non-BT cotton crop exhibited 34.07 and 40.52 after 2 days, 54.49, after 4 days and 75.28 and 74.92 after 6 days respectively.