Main Cotton Research Articles

Eficácia da mistura Acetamiprid + Fipronil, aplicados em tratamento de sementes de algodão, no controle de Aphis gossypii Glover (Hemiptera: Aphididae)

The cotton aphid, Aphis gossypii Glover (Hemiptera; Aphididae), is one of the main cotton crop pests and the use of insecticides is important in its control. The objective of this study was to evaluate of the efficiency of mixture of acetamiprid and fipronil insecticides, in dry cotton seed coating, in controlling A. gossypii aphids. The experimental design was of randomized plots with seven treatments and four replications. Cotton seeds, from cv. Delta Opal, were submitted to the following treatments – at g of active ingredient (AI).100kg-1 of seeds: acetamiprid+fipronil - 200+50, 240+60 e 280+70, acetamiprid – 210, fipronil - 70, tiametoxam - 210 and control (without insecticide). After plants emergency, aphids on leafs of ten plants per plot were evaluated. The pest population was least on cotton crop under seed treatment with acetamiprid+fipronil, acetamiprid and tiametoxam. The mixture of acetamiprid and fipronil was effective in controlling A. gossypii in cotton crop, even at 200+50 g AI.100kg-1 of seeds, by causing 93, 82 and 93% of mortality, at 11th, 15 th and 21th days after seedling emergence, respectively.

Isolation of five new monosomic alien addition lines of Gossypium australe F. Muell in G. hirsutum L. by SSR and GISH analyses

With 2 figures and 3 tables Abstract Gossypium australe F. Muell (2n = 2x = 26) is a wild perennial species possessing agronomic useful traits that would be interesting to introgress into G. hirsutum L. (2n = 4x = 52), the main cultivated cotton species. To isolate monosomic alien addition lines (MAALs) of G. australe in G. hirsutum, the [2(G. hirsutum × G. australe) × G. hirsutum] pentaploid (2n = 5x = 65) was backcrossed as male parent to G. hirsutum. Analysis of 42 BC1 plants and seven alien addition lines, already available, with 150 SSR markers developed from G. hirsutum revealed a cross‐species amplification rate of 100% and a polymorphism rate of 56%. Eighty polymorphic SSR markers generated 87 G. australe‐specific loci that have been assigned by a hierarchical cluster analysis to 13 linkage groups corresponding to the 13 chromosomes of G. australe. Analysis by SSR markers and genomic in situ hybridization of the self‐progeny of disomic alien addition lines, backcross progeny of the pentaploid, allowed the isolation of five new MAALs.

Characterization of Rhizoctonia spp. Isolates Associated with Damping-Off Disease in Cotton and Tobacco Seedlings in Greece.

Isolates of Rhizoctonia spp. were obtained during the spring of 2007 from diseased cotton and tobacco seedlings showing damping-off symptoms. The sampled fields were located in the main cotton- and tobacco-cultivating regions of central and northern Greece. Among the 79 isolates obtained from cotton plants, 17 were binucleate and 62 were multinucleate whereas, among the 89 isolates obtained from tobacco plants, 87 were multinucleate and only 2 were binucleate. Characterization of anastomosis groups (AGs) was performed with hyphal anastomosis reactions using tester isolates of known AG groups. Anastomosis reactions in cotton mutlinucleate isolates showed that 54 of them belonged in Rhizoctonia solani AG-4, 6 in AG-7, 1 in AG-2, and 1 in AG-3. In the 87 tobacco multinucleate isolates, anastomosis reactions showed that 70 of them belonged in R. solani AG-2, 16 in AG-4, and 1 in AG-5. In addition, molecular characterization was carried out using the specific ribosomal DNA internal transcribed spacer region, in a randomly selected number of isolates. In cotton, the most prevalent AG was AG-4, with 18 isolates to the subgroup HG-I, 1 isolate to the subgroup HG-II, and 7 isolates to the subgroup HG-III, followed by AG-7 (7 isolates), AG-2-1 (1 isolate), and AG-3 (1 isolate). In tobacco, the most prevalent group was AG-2-1 (70 isolates), followed by AG-4 (6 isolates to the subgroup HG-I and 5 isolates to the subgroup HG-III) and a single isolate belonging to AG-5. Phylogenetic analysis showed that the isolates were distinctly separated based on their AG types. Pathogenicity and aggressiveness of the isolates to several hosts was determined. AG-4 isolates from either cotton or tobacco were the most aggressive on the hosts tested, while AG-2-1 isolates were of moderate aggressiveness and were not pathogenic on barley.

BRS 293: A midseason high-yielding upland cotton cultivar for Brazilian savanna

Cotton cultivar BRS 293 is a midseason high-yield cultivar and has wide adaptation to the Brazilian savanna, yield stability, desirable resistance to main cotton diseases and good fiber quality. The cultivar BRS 293 meets growers' demands for competitive lint yield as well as fulfilling industrial textile requirements.

Using geographic information systems to map the prevalent weeds at an early stage of the cotton crop in relation to abiotic factors

Cotton is still one of the most important crops in Greece despite the changes in the country’s socioeconomic status which have reduced the total cultivated area. In order to minimize yield losses, weed control is essential during the cultivation period. The aim of this study was to determine the distribution of the prevalent weeds that escape the usual herbicide application in the main cotton zone, located in the Karditsa prefecture. The weed densities and the irrigation methods used were recorded in 101 sampling sites of 25 m2; the cotton crop had been grown for the last 5 years using similar weed control techniques. Existing soil maps of the area were also used, through which soil data (texture and carbonates content) were accessed. Among the 14 weed species that have been recorded, four were perennial (Cyperus rotundus, Convolvulus arvensis, Cynodon dactylon, Sorhum halepense) and were ranked as first, second, fourth and fifth, respectively, according to the mean density, indicating the inefficient herbicidal control. In the fields irrigated by sprinklers, the weeds occurred in greater populations than those that occurred in fields irrigated by drippers, at values of 4.64 and 3 weeds m-2, respectively. In terms of the studied soil properties, the distribution of C. arvensis was significantly correlated with carbonate content and soil texture in the surface soil layer. The autocorrelation analysis showed that only perennial weeds are spatially correlated whereas the interpolated maps showed this spatial trend of weed appearance.

La transición entre dos ciclos y sus efectos sociales en un territorio argentino: Conflictos de convivencia en el Chaco ante una nueva etapa colonizadora (1920-1940)

The years that pass from 1920 to 1940 represent an essential period to understand the territorial space known as “Chaco” ‐in the north of Argentina‐, particularly for their socioeconomic evolution. During that time its productive profile was formed characterize this jurisdiction by several decades, consolidating itself like the main cotton region of the country, and receiving internal and external immigrants. This process, known as the cotton cycle in distinction to the previous model denominated forest cycle, was characterized by the incorporation of human contingent destined to the colonization and manual tasks that the crops demanded and harvests of the textile. Social problems derived from this affluence; the conflicts of coexistence in the rural scopes; and the answers of the State and the society, are the field of study of this article.

The breeding of two polyploid rice lines with the characteristic of polyploid meiosis stability

Polyploidization is a basic feature of plant evolution. Nearly all of the main food, cotton and oil crops are polyploid. When ploidy levels increase, yields double; this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice. Because low seed set rates in polyploid rice usually makes it difficult to breed, the selection of Ph-liked gene lines was emphasized. After progenies of indica-japonica were identified and selected, two polyploid lines, PMeS-1 and PMeS-2 with Polyploid Meiosis Stability (PMeS) genes were bred. The procedure included seven steps: selecting parents, crossing or multiple crossing, back-crossing, doubling chromosomes, identifying the polyploid, and choosing plants with high seed set rates that can breed themselves into stable lines. The characteristics of PMeS were determined by observing meiotic behaviors and by cross-identification of seed sets. PMeS-1 and PMeS-2, (japonica rice), have several characteristics different from other polyploid rice lines, including a higher rate of seed set (more than 65%, increasing to more than 70% in their F1 offspring); and stable meiotic behaviors (pairing with bivalents and quarivalents nearly without over-quarivalent in prophase, nearly without lagging chromosomes in metaphase and without micronuclei in anaphase and telophase). The latter was obviously different from control polyploid line Dure-4X, which displayed abnormal meiotic behaviors including a higher rate of multivalents, univalents and trivalents in prophase, lagging chromosomes in metaphase and micronuclei in anaphase and telophase. There were also three differences of the breeding method between PMeS lines and normal diploid lines: chromosomes doubling, polyploidism identifying and higher seed set testing. The selection of PMeS lines is the first step in polyploid rice breeding; their use will advance the progress of polyploid rice breeding, which will in turn offer a new way to breed super rice.

Timing of planting is crucial for cotton yield

A field study has been conducted to evaluate the importance of planting dates on earliness and second crop seed cotton yield in two cotton cultivars (Gossypium hirsutum L.). The experiment was designed as a split-plot with three replications in which planting dates were the main plots and cotton cultivars were subplots. Five planting dates were established at about 15-day intervals from mid-April to mid-June (15 April, 1 May, 15 May, 1 June, and 15 June). Data collected in both years indicated that planting on 15 April increased the seed cotton yield by 15%. 1 June planting resulted in lower yield (28%), micronaire (15%) and strength (10%) compared to 1 May. Short fibre content was 35% higher for the 15 June planting than for 1 May planting. Cultivar responses differed with planting date. The existence of cultivar×planting date interaction on yield highlights the importance of selecting the right cultivar for the specified planting date. An early planting production system for cotton has the potential to increase yield and quality. Planting cotton as a second crop after cereals could also be feasible for the regions which have an expanding textile industry, although yield and quality are not as high as in crops grown at optimum planting date.

The Influence of Cropping Systems on Weed Communities in the Cotton Fields of Jiangsu Province

The overall weed infestation indexes and density of all weed populations occurr ing in both the rice_cotton crop rotation and continuous dry_cropping sys tems of the main cotton belts in Jiangsu Province were surveyed over five years continuously. The succession patterns of weed communities and weed occurrence we re studied through statistical analysis in space and time. The results showed th at there was a close relationship between the structure of weed community and th e level of weed infestation and cropping systems. Under the rice_cotton crop rot ation system, the density of hydrophilous weeds such as Echinochloa crusgalli, Alternanthera philoxeroides and Malachium aquaticum was the highest, whi le that of xerophilous weeds (e.g., Digitaria sanguinalis) was lowest. Ho wever, there was marked linear relationship between abundance and time, with abu ndance of hydrophilous weeds (e.g., E. crusgalli) decreasing, and that of x erophilous weeds as (e.g., D. sanguinalis) increasing with time, when cott on was gro wn continuously in the fields with the rice_cotton rotation system. After four years continuous cotton growing, the structure of weed community seemed to tend to stable condition. In the cotton fields with cotton cropping system, there wer e dense density of xerophilous weeds as dominants and no marked change of weed c ommunity structure between different years. Moreover, the marked difference of w eed community structure and weed density occurred between two different cropping systems. The influence of cropping systems on weed community was much more sign ificant than that of geographical factors.

Mites associated with stored seed cotton and related products in Greece

Samples were taken during a 2-year period (Sept. 1998 to Sept. 2000) from 17 ginning mills, located in the main cotton production regions in Greece. The material was examined in order to determine the presence and relative abundance of mites in stored seed cotton and its products: cotton fiber, cottonseed and cotton gin trash. Twenty-two mite taxa were found, with the predominance of mite species on each type of stored commodity differing significantly. Fifteen taxa were recorded in seed cotton, where the most abundant species wereTyrophagus putrescentiae (Schrank) andTarsonemus waitei Banks. In contrast, only four species were found in cotton fiber, withT. putrescentiae being the dominant one. Nine taxa were recorded in the cottonseed samples, where the most abundant species was by farLepidoglyphus destructor (Schrank).Caloglyphus sp. was the most abundant species in cotton gin trash, where a total of 13 taxa were found. Most mites were found in gin trash, followed by cottonseed and seed cotton; very few mites were detected in cotton fiber.

Distribution and Races of Xanthomonas axonopodis pv. malvacearum on Cotton (Gossypium hirsutum) in Uganda

Surveys in 1995 and 1996 showed that bacterial blight caused by Xanthomonas axonopodis pv. malvacearum occurs throughout the main cotton growing areas of Uganda, causing seedling blight, angular leaf spot and bacterial boll rot. During the vegetative and early fruiting stages of crop growth, severe symptoms of `blackarm' spread from leaves to the stem, causing loss of fruiting branches. A set of Upland cotton cultivars (Gossypium hirsutum) were then used to determine the races of the blight bacterium present in Uganda. Many of the isolates induced moderate to severe symptoms on all the test hosts except 101–102B, indicating infection with race 10 or 18. The next most common isolate was race 7. Races 16 and 6 were also identified and 23% of isolates caused symptoms on all the differential cultivars including 101–102B, results indicating the presence of a race of the pathogen which may be the same as that identified in countries neighbouring Uganda and designated as race 20.

Insecticide resistance in five major insect pests of cotton in India

Insecticide resistance to representatives of commonly used insecticide groups (pyrethroids—cypermethrin; organophosphates—chlorpyriphos; cyclodienes—endosulfan) was determined in five major insect pests of cotton from the main cotton growing regions of India with emphasis on Andhra Pradesh and Maharashtra. The cotton bollworm Helicoverpa armigera (Hubner) exhibited widespread resistance to cypermethrin with 23–8022-fold resistance being recorded in field strains. Resistance to endosulfan and chlorpyriphos was low to moderate in H. armigera. The overall resistance of the pink bollworm Pectinophora gossypiella (Saunders) to pyrethroids was low. However, high resistance levels of 23–57-fold to endosulfan were recorded in some areas of Central India. Resistance to chlorpyriphos was high in the Medak, Bhatinda and Sirsa strains from North India. The majority of the Spodoptera litura (Fab.) strains collected in South India exhibited high resistance levels of 61–148-fold to cypermethrin. Resistance to endosulfan was high only in two strains, collected from Bhatinda and Karimnagar in North India. The S. litura strains from South India exhibited high levels of resistance at 45–129-fold to chlorpyriphos. Insecticide resistance in Earias vittella (Fab.) was low to moderate in the Sirsa and Sriganganagar strains from North India. Bemisia tabaci (Genn.) exhibited moderately high levels of resistance to cypermethrin, but resistance to endosulfan and chlorpyriphos was negligible in the field strains tested. The implications of resistance for cotton pest management in India are discussed.

Susceptibility of Upland Cotton Cultivars to <I>Bemisia tabaci</I> Biotype B (Homoptera: Aleyrodidae) in Relation to Leaf Age and Trichome Density

The relationships between leaf trichome densities, leaf age, and sweetpotato whitefly, Bemisia tabaci (Gennadius) biotype B, infestations of 13 upland cotton, Gossypium hirsutum L., cultivars were investigated in 1990 and 2000. Stoneville 474 supported higher numbers of B. tabaci biotype B eggs, nymphs and adults, and also had higher numbers of stellate trichomes on abaxial leaf surfaces compared with other cotton cultivars. Siokra L-23, in general, had fewer stellate trichomes and also fewer whiteflies. However, the positive trichome–whitefly density relationships were affected by the ages of leaves from different main stem cotton nodes. The youngest leaves on main stem node 1 below the terminal for all cultivars had higher numbers of stellate trichomes but fewer whiteflies compared with older leaves.

Organochlorine and organophosphorus pesticide residues in the Atoya river basin, Chinandega, Nicaragua

The hydrographic basin of the Atoya river, located in the Department of Chinandega, one of the main cotton producing regions in Nicaragua, is intensively contaminated by pesticides. Samples of river waters and sediments, as well as strategically selected wells have been analyzed to study variations in the concentrations of organochlorine and organophosphorus pesticide residues between the dry season (November–April) and the rainy season (May–June). Generally, higher concentrations of pesticides have been detected in the river waters and sediments in the dry season. DDT, DDD, DDE compounds and toxaphene are the most frequent organochlorine residues found in the water and sediment samples, while endrin, aldrin, dieldrin and lindane are mainly found in the waters of rivers and wells. Organophosphorus compounds were rarely detected. However, residues of ethion, methyl-parathion and ethyl-parathion were found in high concentrations in some river and well water samples. Generally, organochlorine compounds tend to accumulate in the fine grain-size fractions, rich in organic matter, except DDE, which concentrates basically in the coarse grain-size fractions.

Devaluation and Competitiveness: Evidence from the Tea and Cotton Textiles Industries

This paper measures the effect of currency rate changes on the competitive ness of India’s main export industries, Tea and Cotton Textiles. In contrast to the conventional approach that uses data from commodity markets, the present study is based on data from stock markets. The analysis is done in two parts. The first part reports estimates of somewhat significant currency rate exposure of the major Tea and Cotton Textiles exporting firms in India and other coun tries. The second part reports the movements of the average excess returns of the exposed Indian firms, based on an event-study of the devaluation of the Rupee in 1991. The theory behind the econometric models invokes only the effi ciency property of financial markets and seems less controversial than its coun terpart in the conventional approach. (JEL Classification: F0)

Field Performance of Cottons Expressing Transgenic CryIA Insecticidal Proteins for Resistance to Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae)

Transgenic cotton plants (BTK lines), carrying a gene construction that codes for the CryIA(b) or CryIA(c) 8-endotoxins from Bacillus thuringiensis variety kurstaki were evaluated in the field for resistance to naturally occurring tobacco bud worm, Heliothis virescens (F.), boll worm, Helicoverpa zea (Boddie), and cabbage looper, Trichoplusia ni (Hubner). Five BTK lines (each line was an independent insertion event) were evaluated in 1990 and 6 in 1991. Also 2 nontransgenic commercial cultivars, ‘Coker 312’, the explant source cultivar for the BTK lines, and an adapted cultivar, ‘Stoneville 453’, were evaluated. A split-plot design was used with lepidopteran control as the main plot and cotton lines as the subplots. Main plot treatments were weekly spray applications of insecticide for lepidopteran control during 8 or 9 wk of the growing season, or no insecticidal sprays for lepidopteran control. The season mean numbers of tobacco bud worm and boll worm larvae on plant mainstem terminals, flower buds and capsels, and the percentage of flower buds and capsels injured were lower for all BTK lines, in sprayed and unsprayed plots, than for the 2 nontransgenic cultivars. Averaged over both years, the season mean percent injury in plots of the unsprayed Coker 312 was ≈23% of the flower buds and 12% of the capsels. In unsprayed plots of the BTK lines, the season mean percent injury was ≈2.3 of the flower buds and 1.1 of the capsels. In unsprayed plots, the number of cabbage looper larvae and the amount of cabbage looper feeding injury to leaves also was lower on the BTK lines compared with the 2 nontransgenic cultivars. Using the recommended treatment thresholds for tobacco bud worm and boll worm of 8-15% injured flower buds, none of the BTK lines would have been treated, whereas injury in the 2 nontransgenic cultivars would have required multiple insecticide applications. Averaged over both years, the yield of unsprayed Coker 312 was 1,050 kg/ha and the average of all the unsprayed BTK lines was 1,460 kg/ha. Expression of these cryIA genes in Coker 312 cotton resulted in greater yield, 408 kg/ha, 38.8%, in the presence of lepidopteran pests. The use of these insect resistant BTK lines or equally efficacious commercial BTK cultivars in production agriculture should reduce insecticide applications for tobacco bud worm, boll worm, and cabbage looper while increasing farm profit and opportunities for the use of biological control.

The Shetland environment, the establishment of the Sullom Voe Environmental Advisory Group, development of Shetland Oil Terminal Environmental Advisory Group and its monitoring strategy

The Shetland Islands lie between latitudes of approximately 60° and 61° North, over 100 miles north of the Scottish mainland. They are influenced by the North Atlantic Drift so that the climatic conditions are much less severe than for other land masses, for example in Southern Greenland where the mean temperature for five months of the year is below freezing. The environment in all its considerable heterogeneity is well described in The Natural Environment of Shetland (Goodier 1974) and in The Natural History of Shetland (Berry & Johnston 1980). Briefly the islands lie on the western oceanic fringe of Europe, have approximately 1450 kilometres of coastline and an area of 1468 square kilometres. The geology is varied and geomorphologically the islands constitute a drowned range of glaciated hills situated on the continental shelf. The coast consists of extensive areas of cliffs and voes with relatively few beaches. In general, the ‘outer’ coasts, especially on the west, are exposed high energy environments. In contrast, the inner coasts, often voes, are deep sheltered inlets. The land itself tends to be hilly and, where it has not been stripped for agricultural use, is blanketed with peat, with the main vegetation heather (Calluna vulgaris) and cotton sedge (Eriophorum angustifolium). Approximately 10% of the land is covered by rushy vegetation and there is very little relict scrub though there are one or two planted woodland plots. The original scrub was largely eradicated by man who arrived in Shetland from Iberia about 3500 BC. Colonisers from Scandinavia arrived in the eighth century and have had a lasting influence on the culture of the islands. In 1971 the human population was about 17327 and in 1989 was 23 214 (SIC 1992).

Status and environmental impact of toxaphene in the Third World — A case study of African agriculture

Toxaphene was early introduced to Egypt by Hercules Co. in 1955 to combat the main cotton insect pests: the cotton leaf worm Spodoptera littoralis, the pink bollworm Pectinophera gossypiella, and the spiny bollworm Earias insulana. Formulated Emulsfiable concentrate (E.C.). Toxaphene (60% Chlorinated camphene) was used in four successive sprays during the cotton season on an area of 1.5 million acres at the rate of 2L/acre during the first three seasons (1956–1958). The rate was then increased to 3L/acre during the next two seasons (1959–1960). In the 1961 season, a disaster occurred when toxaphene even at 4L/acre failed to stop the infestation outbreak of the cotton leaf worm resulting in a loss of 50% of the national cotton yield of that season. This failure was caused by the build up of cotton leaf worm resistance to toxaphene. The total amount of toxaphene used during these six seasons was estimated to be 54,000 metric tons of the active ingredient. Although the use of Toxaphene in Egypt was banned in 1962 due to the irreversible cotton leaf worm resistance, new sources of toxaphene residues kept comming to Egypt across the River Nile Basin countries which were still heavily using toxaphene (Sudan, Ethiopia, Tanzania and Congo). As well, the illegal use of toxaphene by fishermen was another source of toxaphene pollution. The residues of toxaphene seem to be quite persistent as shown by the few studies carried out. Levels up to 10 ppm were detected in the River Nile water, soil and other biological samples in the Egyptian environment. (Saleh, 1981). Long term exposure to sublethal levels are expected to be a potential hazard to human health and the environment. A follow up program to monitor and assess the risk and hazards of toxaphene exposure is suggested for implementation in Egypt as a model for developing countries heavily exposed to toxaphene residues.

Residue levels of organochlorines and mercury in cattle egret, bubulcus ibis, eggs from the Faiyum Oasis, Egypt.

In Egypt, the Cattle Egret Bubulcus ibis is a common resident bird of the Nile Valley, the southern part of the Nile Delta, and the Suez Canal area. In the 1970s it disappeared as a breeding bird from the greater part of the Nile Delta, as did several other bird species, notably birds of prey. Only in recent years some of the species that had declined are markedly recovering, such as the Black-shouldered Kite Elanus caeruleus and the Cattle Egret. There is circumstancial evidence that these birds declined - at least partially - as a result of pesticide use in the main cotton growing areas, but this has never been substantiated. The recent recovery of some bird populations, commencing in the 1980s, coincides with a general shift from the use of organochlorines (except for endrin and HCH which are still in use) towards synthetic pyrethroids, organophosphates and carbamates in Egyptian agriculture: 30 million kg of formulated product annually, of which 70% are applied to cotton. The number of breeding pairs of Cattle Egrets in a well-known colony at Giza (30[degrees].01'N 31[degrees].13'E) steadily declined from 2500 in 1977 to 1100 in 1984. Therefore, it was decided to collect some eggs formore » residue analysis. Cattle Egrets are not piscivores, such as most other egrets, but mainly insectivores. They feed in agricultural areas and likely are good indicators for pesticide use in these habitats. Based on gizzard contents analysis, Kirkpatrick (1925) concluded that Cattle Egrets in Egypt only occasionally take (semi) aquatic prey, such as toads, and further predominantly Orthoptera and Diptera on arable land. Various studies have been published with respect to pesticides or heavy metals in the Egyptian environment but, surprisingly, birds have been almost completely ignored. The data presented are the first residue analyses of bird eggs from an agricultural area in Egypt, and as such they can be considered as baseline data for future research. 36 refs., 2 tabs.« less

Farm location and farmers’ performance on the Hamza minor canal

A sample of 36 tenant farmers, at varying locations along the Hamza Minor Canal of the Sudan Gezira Scheme, were surveyed in 1986/7, the purpose being to estimate locational variation in irrigation water supplies and. tenancy income levels. Results show that for the main crop, cotton, there are declines in water balance, crop yields and net returns between head, middle and tail end of the canal. However, in middle and tail‐end locations groundnuts yield a substantially higher net return per hectare than the main crops, cotton and wheat, which suggests that changes in crop rotations would be profitable.