Cotton Leaf Curl Virus Research Articles

Agronomic Performance of Transgenic and Non Trangenic Cotton against Cotton Leaf Curl Virus

The present study was carried out to increase the level of tolerance in Gossypium hirsutum L. against cotton leaf curl disease (CLCuD). Hybridization of a transgenic line (anti-sense tRep gene) with three naturally resistant (non-transgenic) varieties namely FH-1000, MNH-786 and NIBGE-115 was performed. The parents and their F1 Hybrids were evaluated for disease infectivity. Data of some morphological traits (Plant Height, Monopodial Branches per Plant, Sympodial Branches per Plant, Number of Boll per Plant, Lint Percentage, Boll Weight, Staple Length, Staple Strength, Fiber Fineness, Yield of Seed Cotton ) was evaluated satanically to check the influence of disease on morphology of plant. The results showed that hybridization increased the tolerance level against cotton leaf curl virus.

First report on the association of a begomovirus with chrysanthemum indicum exhibiting yellowing of leaf vein disease characterized by molecular studies

ABSTRACT Infected leaf samples of an ornamental plant Chrysanthemum indicum showing yellowing of leaf veins were collected from gardens of New Delhi (India). An expected PCR product of size ~500 bp was amplified from total DNA extracts of symptomatic leaf samples with universal primers on the gene of coat protein region of begomovirus DNA-A component. The presence of begomoviruses was also confirmed by Southern blot analysis using control cloned DNA-A probe of Cotton leaf curl virus. Sequence analysis of the virus infecting Chrysanthemum indicum showed 99% nucleotide sequence identity with Clerodendron yellow mosaic virus (EF408037).

PERFORMANCE OF SOME ADVANCED GENOTYPES OF COTTON IN TERMS OF CMT, CLCuV AND YIELD

ABSTRACT Cotton leaf curl virus (CLCuV) and heat stress are the major threats to cotton productivity in Pakistan. Both these factors inflicted huge losses in recent years. Thirty one genotypes of Gossypium hirsutum L. were sown in the experimental area of Cotton Research Institute, Faisalabad, Pakistan, on 25th of May for the purpose of screening against aforementioned stresses. Analysis of variance revealed significant variation among the tested genotypes. Some of the genotypes showed promising results in terms of CLCuV and also showed fair stability of their membranes. The strain FH- 142 showed excellent tolerance level against CLCuV and heat stress by showing the values of 0.4% for cotton leaf curl virus and membrane stability of 46.1%. The other genotypes that showed promising results in terms of CLCuV % are FH-330, MNH-886, MNH-814 and FH-312 and regarding heat stress MNH-456, FH-142, FH-118, CRSM- 38 and NIAB-112 exhibited promising results by showing the CMT % of 46.4%, 46.1, 45.5, 45.5, 44.1, and 41.9%, respectively. The findings of the experiment may be helpful in designing breeding programmes regarding CLCuV and heat tolerance as material had considerable potential for better yield as well.

Correlation of meteorological parameters and remotely sensed normalized difference vegetation index (NDVI) with cotton leaf curl virus (CLCV) in Multan

Climate change and weather has a profound effect on the spread of Cotton Leaf Curl Virus (CLCV) which is transmitted by whitefly. Climate change is altering temperature and precipitation patterns, resulting in the shift of some insect/pest from small population to large population thus effecting crops yield. To find out the relationship between the weather conditions, outburst of CLCV and changes in Normalized Difference Vegetation Index (NDVI) values due to the outburst of CLCV, a study was carried out for tehsil Multan. Data was acquired for the months of June, July, August and September for the year 2010. Regression analysis between CLCV and meteorological conditions as well as between CLCV and NDVI was performed. Meteorological parameters included temperature, humidity, precipitation, cloud cover, wind direction, pan evaporation and sunshine hours. NDVI values were calculated from SPOT satellite imagery (1km) using ArcMap10 and WinDisp v5.1. Correlation coefficients obtained in most of the cases were acceptable however the significance F and P-value were higher than their critical value at 95% level of significance. Therefore significant correlation was found only between CLCV and temperature and between CLCV and PAN evaporation during the month of July.

AN INSIGHT OF COTTON LEAF CURL VIRUS: A DEVASTATING PLANT PATHOGENIC BEGOMOVIRUS

Genome of plant viruses consists of either RNA or DNA. DNA viruses can be categorized into two types, (1) circular double-stranded DNA (dsDNA), these viruses are able to replicate through the process of reverse transcription from RNA (the caulimoviruses and badnaviruses), (2) viruses that have circular single-stranded DNA (ssDNA), which replicate through a dsDNA intermediate (the Geminivirus and nanoviruses). Begomoviruses are whiteflies transmitted geminiviruses and infect many economically important dicotyledonous crops including cotton, potato, tomato, cassava and chili. Begomoviruses cause leaf curl disease in cotton. In this review article, the Cotton Leaf Curl Virus (CLCuV) has been introduced systematically.

Registration of NN‐3 Cotton

NN‐3 cotton (Gossypium hirsutum L.) germplasm line (Reg. No. GP‐955, PI 665058) (Pak 027493) was developed by the Plant Genomics and Molecular Breeding Labs of the National Institute for Biotechnology and Genetic Engineering (NIBGE) Faisalabad, Pakistan, as a part of efforts for evolving cultivars resistant to the Burewala strain of cotton leaf curl disease (CLCuD; caused by Cotton leaf curl virus). This line was developed through crossing S‐12, a high‐yielding variety but one that is susceptible to CLCuD, and LRA‐5166, which is resistant to the Multan strain of the disease. The line was tested in various trials conducted by NIBGE as well as by various national agencies. In varietal trials conducted for three successive normal cotton‐growing seasons (2005 through 2007) at three different sites—the Cotton Research Station (CRS) Vehari, the CRS/Central Cotton Research Institute at Multan, and NIBGE Faisalabad—NN‐3 has shown high tolerance against the virus disease. In a national coordinated varietal trial, NN‐3 produced higher seed‐cotton yield than the standards for two consecutive years (2008 and 2009). NN‐3 has been cited as the most tolerant cotton line to the Burewala strain of CLCuD. This line is being extensively used as one of the parents for developing elite cotton cultivars that show high tolerance to the disease. This line would be a valuable genetic resource for use in future cotton breeding programs as a step toward sustaining cotton production in the country.

Arsenophonus GroEL Interacts with CLCuV and Is Localized in Midgut and Salivary Gland of Whitefly B. tabaci

Cotton leaf curl virus (CLCuV) (Gemininiviridae: Begomovirus) is the causative agent of leaf curl disease in cotton plants (Gossypium hirsutum). CLCuV is exclusively transmitted by the whitefly species B. tabaci (Gennadius) (Hemiptera: Alerodidae). B. tabaci contains several biotypes which harbor dissimilar bacterial endo-symbiotic community. It is reported that these bacterial endosymbionts produce a 63 kDa chaperon GroEL protein which binds to geminivirus particles and protects them from rapid degradation in gut and haemolymph. In biotype B, GroEL protein of Hamiltonella has been shown to interact with Tomato yellow leaf curl virus (TYLCV). The present study was initiated to find out whether endosymbionts of B. tabaci are similarly involved in CLCuV transmission in Sriganganagar (Rajasthan), an area endemic with cotton leaf curl disease. Biotype and endosymbiont diversity of B. tabaci were identified using MtCO1 and 16S rDNA genes respectively. Analysis of our results indicated that the collected B. tabaci population belong to AsiaII genetic group and harbor the primary endosymbiont Portiera and the secondary endosymbiont Arsenophonus. The GroEL proteins of Portiera and Arsenophonus were purified and in-vitro interaction studies were carried out using pull down and co-immunoprecipitation assays. In-vivo interaction was confirmed using yeast two hybrid system. In both in-vitro and in-vivo studies, the GroEL protein of Arsenophonus was found to be interacting with the CLCuV coat protein. Further, we also localized the presence of Arsenophonus in the salivary glands and the midgut of B. tabaci besides the already reported bacteriocytes. These results suggest the involvement of Arsenophonus in the transmission of CLCuV in AsiaII genetic group of B. tabaci.

CRSM-38, a new high yielding coupled with CLCuV tolerance cotton (Gossypium hirsutum L.) variety

CRSM-38 is a high yielding and leaf curl virus tolerant cotton variety, developed in Pakistan. Hybridization and subsequent pedigree method’s selection work was carried out under natural field conditions at Cotton Research Station, Multan during the year 2001 and 2002 by using a virus tolerant strain (583-85/99) and a variety (FH-900). The new variety exhibited an average of 77.9% higher degree of tolerance against cotton leaf curl virus (CLCuV) over respective checks, and attained an average of 46.52 % higher seed cotton yield than that of CIM-496 under various climatic conditions revealing its wider adaptability. It possesses harmonious combination of fiber traits, that is, 39.94% ginning out turn (GOT), 29.07 mm fiber staple length, 4.38 ig/inch fiber micronaire and 31.38 g/tex fiber strength. Significant differences among genotypes showed higher degree of genetic variability, heritability (78 to 90%) and genetic advance (38 to 63.90%) in seed cotton yield suggesting that these genetic components were under the control of additive genetic effects, whereas tolerance to CLCuV could be improved through selection for high seed cotton yield. On the basis of the aforementioned features, CRSM-38 was recommended for general cultivation by Punjab Seed Council during the year 2009. Key words : Gossypium hirsutum L ., CRSM-38, seed cotton yield, cotton leaf curl virus (CLCuV), heritability, additive genetic effect, genetic advance.

High plant density by narrow plant spacing ensures cotton productivity in elite cotton (Gossypium hirsutum L.) genotypes under severe cotton leaf curl virus (CLCV) infestation

This study was conducted to compare the seed cotton yield and cotton leaf curl virus (CLCV) infestations of newly evolved cotton genotypes (MNH-886, MNH-814 and CIM-496) under different plant spacings (15.0, 22.5, 30.0, 37.5 and 45.0 cm) at Cotton Research Station (CRS), Multan (71.43°E, 30.2°N and 122 m above sea level), Pakistan, during two consecutive years, that is, 2008 and 2009. The results indicate that cotton sown with 15 cm spaced plants resulted in maximum seed cotton yield only due to highest plant density (88,888 plants ha‑1), as cotton sown with 30 and 45 cm spaced plants (44,444 and 29630 plants ha‑1, respectively) had more number of bolls per plant in both years. Plant spacing had non-significant effects on boll weight and CLCV infestations. Genotypes (MNH-886 and MNH-814) resulted in the highest boll weight, number of bolls per plant and higher seed cotton yield compared with CIM-496 because of about 20% lower CLCV attack. Plant population was statistically similar for all cotton genotypes. In summary, cotton genotypes MNH-886 and MNH-814 resulted in higher seed cotton yield when sown with 15 cm plant spacing. Key words: Cotton, genotypes, plant spacing, seed cotton yield, cotton leaf curl virus (CLCV).

Role of epicuticular waxes in the susceptibility of cotton leaf curl virus (CLCuV)

Cotton leaf curl virus (CLCuV) is the causal agent of the damaging disease of cotton that is caused by number of begomaviruses and vectored by silver leaf whitefly. In the present study, an attempt was made by infecting Gossypium arboreum variety 786, its wax mutant GaWM3 along with Gossypium hirsutum MNH-93 with viruliferous whiteflies. The presence of symptoms on leaves and amplification by PCR for virus in G. hirsutum MNH-93 and wax mutant GaWM3 but not in G. arboreum variety 786 clearly determined the presence of virus in G. hirsutum MNH-93 and wax mutant GaWM3 but not in G. arboreum variety 786. The results indicate that wax may act as physical barrier and provide hindrance in transfer of virus by whitefly.

Investigation of simple sequence repeats (SSR) marker-assisted genetic diversity among upland Bt- and non Bt-cotton varieties

Genetically modified with insect resistance gene (Cry1AC) and hybrid Bt-cotton genotypes were developed to redress cotton leaf curl virus epidemic. In this study, genetic diversity of 6 Bt- and 14 nonBt upland cotton genotypes was detected using simple sequence repeats (SSR) or micro-satellite markers. Out of 31 primer pairs, only 7 (22.6%) yielded polymorphic amplicons of 80 to 340 bp. The average loci per primer were 3.16 and 78.6% of them were informative. The unweighed pair-group method with arithmetic averages (UPGMA) dendrogram placed Bt- and non-Bt cotton varieties into four major groups. With the exception of 4 accessions (being similar), genetic dissimilarity coefficient among all other genotypes ranged from 0.50 to 0.98 suggesting a wide genetic heterogeneity among the selected collection. The lowest similarity was found between BH-160 and CIM-482, CIM-496 and MNH554, BH-160 and CIM-473, SARMAST and BH-160 (non-Bt cultivars), respectively as were some Btcultivars. In contrast to previous reports, these results show that some Bt- and non-Bt-cotton cultivars form a genetically diverse population. They could be used in future breeding programmes to develop new elite cotton cultivars.

Comparative performance of Bt cotton with some elite conventional cotton cultivars under arid to semi-arid conditions

oN, longitude 72.36 o E and altitude 157.65 m. The results revealed that plant growth parameters like plant height, number of bolls plant -1 and seed cotton weight boll1 , were differed significantly (P < 0.05) among Bt and non-Bt cotton cultivars. Seed cotton yield and fiber quality parameters such as maturity percentage, micronaire value, staple length, fiber strength and virus infection percentage were also significantly (P < 0.05) different among different cultivars. Bt -1 21 had maximum value for seed cotton weight boll-1 and maturity percentage and produced 26% higher seed cotton yield than all other cultivars. Furthermore, it also showed 58% less cotton leaf curl virus infection compared to other cultivars. BH-162 produced fiber with maximum length and fineness but it appeared most vulnerable to virus attack. It was concluded that Bt -1 21 performed best in most of the studied traits than other cultivars and may be recommended for cultivation in areas having arid to semi-arid climatic conditions.

Engineering cotton (Gossypium hirsutum L.) for resistance to cotton leaf curl disease using viral truncated AC1 DNA sequences

Several important biological processes are performed by distinct functional domains found on replication-associated protein (Rep) encoded by AC1 of geminiviruses. Two truncated forms of replicase (tAC1) gene, capable of expressing only the N-terminal 669 bp (5'AC1) and C-terminal 783 bp (3'AC1) nucleotides cloned under transcriptional control of the CaMV35S were introduced into cotton (Gossypium hirsutum L.) using LBA4404 strain of Agrobacterium tumefaciens to make use of an interference strategy for impairing cotton leaf curl virus (CLCuV) infection in transgenic cotton. Compared with nontransformed control, we observed that transgenic cotton plants overexpressing either N-terminal (5'AC1) or C-terminal (3'AC1) sequences confer resistance to CLCuV by inhibiting replication of viral genomic and β satellite DNA components. Molecular analysis by Northern blot hybridization revealed high transgene expression in early and late growth stages associated with inhibition of CLCuV replication. Of the eight T(1) transgenic lines tested, six had delayed and minor symptoms as compared to nontransformed control lines which developed disease symptoms after 2-3 weeks of whitefly-mediated viral delivery. Virus biological assay and growth of T(2) plants proved that transgenic cotton plants overexpressing 5'- and 3'AC1 displayed high resistance level up to 72, 81%, respectively, as compared to non-transformed control plants following inoculation with viruliferous whiteflies giving significantly high cotton seed yield. Progeny analysis of these plants by polymerase chain reaction (PCR), Southern blotting and virus biological assay showed stable transgene, integration, inheritance and cotton leaf curl disease (CLCuD) resistance in two of the eight transgenic lines having single or two transgene insertions. Transgenic cotton expressing partial AC1 gene of CLCuV can be used as virus resistance source in cotton breeding programs aiming to improve virus resistance in cotton crop.

Isolation and identification of differentially expressed genes between Gossypium arboreum and Gossypium hirsutum species

Plants have evolved sophisticated molecular defense mechanisms in order to survive disease conditions. So far, a number of pathogen resistance (R) genes have been reported in plants. These R genes are thought to be involved in activating the signals that lead to disease resistance. The structural specificity of R genes products makes it possible to isolate these genes from plants by homology based techniques. Knowledge regarding molecular organization of R genes in cotton is limited and other resistant gene analogues (RGAs) still need to be identified for Cotton Leaf Curl Disease (CLCuD) resistance, particularly from Gossypium arboreum . This study has, therefore, been designed to identify the natural resistance related genes from G ossypium arboreum against CLCuV. In addition to G. arboreum (resistant to CLCuV), G. hirsutum L . var S12 (highly susceptible to CLCuV), G. hirsutum L. var. CP15/2 and LRA (partially resistant to CLCuV) were used as reference controls to facilitate identification of defense related genes. This paper describes several differentially expressed transcripts through DDRT-PCR on total RNA from G. arboreum and some other tetraploid cotton species. The nucleotide sequence of these genes, when compared to the reported database, indicated that some of the differentially expressed transcripts had homology to the reported R-genes. Key words : Pathogen resistance genes (R-genes), G. arboreum , differential display, cotton leaf curl virus (CLCuV), RT-PCR.

Introgression of cotton leaf curl virus-resistant genes from Asiatic cotton (Gossypium arboreum) into upland cotton (G. hirsutum)

Cotton is under the constant threat of leaf curl virus, which is a major constraint for successful production of cotton in the Pakistan. A total of 3338 cotton genotypes belonging to different research stations were screened, but none were found to be resistant against the Burewala strain of cotton leaf curl virus (CLCuV). We explored the possibility of transferring virus-resistant genes from Gossypium arboreum (2n = 26) into G. hirsutum (2n = 52) through conventional breeding techniques. Hybridization was done manually between an artificial autotetraploid of G. arboreum and an allotetraploid G. hirsutum, under field conditions. Boll shedding was controlled by application of exogenous hormones, 50 mg/L gibberellic acid and 100 mg/L naphthalene acetic acid. Percentage pollen viability in F(1) hybrids was 1.90% in 2(G. arboreum) x G. hirsutum and 2.38% in G. hirsutum x G. arboreum. Cytological studies of young buds taken from the F(1) hybrids confirmed that they all were sterile. Resistance against CLCuV in the F(1) hybrids was assessed through grafting, using the hybrid plant as the scion; the stock was a virus susceptible cotton plant, tested under field and greenhouse conditions. All F(1) cotton hybrids showed resistance against CLCuV, indicating that it is possible to transfer resistant genes from the autotetraploid of the diploid donor specie G. arboreum into allotetraploid G. hirsutum through conventional breeding, and durable resistance against CLCuV can then be deployed in the field.

Phylogenetic Analysis of First Generation Cotton Leaf Curl Virus (CLCuV) Resistant Cotton Varieties

ABSTRACTCotton is a major cash crop of Pakistan. During the last few years, cotton production has been hampered by cotton leaf curl virus (CLCuV) disease. Cotton breeders successfully combated CLCuV by developing resistant varieties, however it resurfaced in 2001, all the varieties proving susceptible. This study was conducted to explore the genetic diversity among cotton varieties approved as first defense line against CLCuV using DNA markers. The four cotton varieties, CIM-448, CIM-1100, FH-900 and FH-901, were subjected to random amplified polymorphic DNA (RAPD) and simple sequence repeats (SSR) finger printing assay to reveal genetic relatedness. A total of 110 RAPD primers were surveyed out of which 16 were found polymorphic. The size of 449 amplified loci ranged from 250 to 1500 bp with an average of 4.08 loci per primer. Similarity matrix revealed 96% similarity among the varieties assayed. For SSR genetic analysis, 92 primer pairs were surveyed and only six primers were found informative. A total of 149 loci were amplified with an average of 1.61 loci per primer. Out of these, 13 loci (8.69%) were informative. The amplicons ranged from 58 to 500 bp. Like RAPD analysis, genetic distance among accessions was just 3%. The results obtained here revealed high similarity among the varieties studied, illuminating the reason why first and second generation of CLCuV resistant cotton varieties became susceptible to the new virus strain. Moreover, the correspondence between SSR and RAPD data sets suggests that either method or a combination of both is applicable to diversity studies in cotton varieties.

Investigation of simple sequence repeats (SSR) marker-assisted genetic diversity among upland Bt- and non Bt-cotton varieties

Genetically modified with insect resistance gene (Cry1AC) and hybrid Bt-cotton genotypes were developed to redress cotton leaf curl virus epidemic. In this study, genetic diversity of 6 Bt- and 14 nonBt upland cotton genotypes was detected using simple sequence repeats (SSR) or micro-satellite markers. Out of 31 primer pairs, only 7 (22.6%) yielded polymorphic amplicons of 80 to 340 bp. The average loci per primer were 3.16 and 78.6% of them were informative. The unweighed pair-group method with arithmetic averages (UPGMA) dendrogram placed Bt- and non-Bt cotton varieties into four major groups. With the exception of 4 accessions (being similar), genetic dissimilarity coefficient among all other genotypes ranged from 0.50 to 0.98 suggesting a wide genetic heterogeneity among the selected collection. The lowest similarity was found between BH-160 and CIM-482, CIM-496 and MNH554, BH-160 and CIM-473, SARMAST and BH-160 (non-Bt cultivars), respectively as were some Btcultivars. In contrast to previous reports, these results show that some Bt- and non-Bt-cotton cultivars form a genetically diverse population. They could be used in future breeding programmes to develop new elite cotton cultivars.

Genetic identity of the Bemisia tabaci species complex and association with high cotton leaf curl disease (CLCuD) incidence in Pakistan

The cotton whitefly, Bemisia tabaci (Gennadius), is a cryptic species complex, and members of the complex have become serious pests in Pakistan because of their feeding and their ability to transmit cotton leaf curl virus (CLCuV). Here, an analysis was made of the identity of B. tabaci collected from cotton and a range of non-cotton hosts in the cotton-growing zones in Punjab and Sindh, the main cotton-producing provinces of Pakistan, using a portion of the mitochondrial cytochrome oxidase 1 gene. The geographic distribution of the different members of the complex was then compared with the incidence of CLCuD. Using the Dinsdale nomenclature, the results revealed three putative species, Asia 1, Asia II 1 and Middle East-Asia Minor 1. Asia II 1 (also referred to in the literature as biotypes K, P, PCG-1, PK1, SY and ZHJ2) was only recorded from Punjab cotton plants, whereas Asia 1 (also referred to in the literature as biotypes H, M, NA and PCG-2) was found in both Sindh and Punjab. Middle East-Asia Minor 1 (commonly known as biotype B and B2) was found only in Sindh. Moreover, Asia II 1 was associated with high incidences of CLCuD, whereas regions where Middle East-Asia Minor 1 was present had a lower incidence. Phylogenetic analysis showed that the Middle East-Asia Minor 1 population in Sindh formed a distinct genetic subgroup within the putative species, suggesting that the Sindh province of Pakistan may form part of its home range. So far, no individuals from the putative species Mediterranean (commonly known as biotypes Q, J and L) have been found in Pakistan. The capacity to manage pests and disease effectively relies on knowledge of the identity of the agents causing the damage. In the case of CLCuD in Pakistan, this knowledge has been obscured to some extent because of the inconsistent approach to identifying and distinguishing the different B. tabaci associated with CLCuD. The situation has now been clarified, and a strong association between disease incidence and vector identity and abundance has been shown. Given this advance, future research can now focus on factors that influence the capacity of different vector species to transmit the viruses that cause CLCuD, the reason for differences in vector abundance and the lack of geographic overlap between the cryptic vector species. This knowledge will contribute to the development of improved methods with which to manage the disease in Pakistan.

Sequence characterization of cotton leaf curl virus from Rajasthan: phylogenetic relationship with other members of geminiviruses and detection of recombination

Diseased cotton plants showing typical leaf curl symptoms were collected from experimental plot of Agriculture Research Station-Sriganganagar, Rajasthan. Complete DNA-A component from samples taken from two areas were amplified through rolling circle amplification (RCA) using templiphi kit (GE Healthcare) and characterized. DNA-A of one isolate consists of 2751 nucleotides and second isolate of 2759 nucleotide. Both sequences comprised six ORF's. Genome organization of DNA-A of one isolate shows high sequence similarity with other characterized local begomovirus isolates of Rajasthan, while other isolate shows high sequence similarity with CLCuV reported from Pakistan. The maximum similarity of first isolate, CLCuV-SG01, shows highest sequence identity with Cotton leaf curl Abohar (Rajasthan) virus, and second isolate, CLCuV-SG02, shows highest sequence identity with cotton leaf curl virus from Pakistan. Both isolates showed 85% similarities with each other. The sequence data revealed probable infiltration of some strains of Cotton leaf curl virus from Pakistan to India, or co-existence of different isolates under similar geographical conditions. While CLCuV-SG01 shows highest nt sequence similarity with CLCuV Rajasthan (Abohar), nt identity of V1 ORF (encoding coat protein) of SG01 shows the highest nt identity (100%) with CLCuV Multan (Bhatinda) and Abohar virus while AC1 region also showed difference. Complete nucleotide sequence of SG01 shows only 86% similarity with CLCuV Multan virus. Similarity search revealed significant difference in AV1 and AC1 regions with respect to DNA-A suggesting an evolutionary history of recombination. Computer based analysis, recombination detection Program (RDP) supports the recombination hypothesis, indicated that recombination with other begomoviruses had taken place within V1 ORF and AC1 ORF of CLCuV-SG01 and AC1 ORF of CLCuV-SG02 and also in noncoding intergenic region (IR).

Registration of ‘CIM‐496’ Cotton

‘CIM‐496’ cotton (Gossypium hirsutum L.) (Reg. No. CV‐125, PI 657627, Pak 024263) was developed by the Central Cotton Research Institute (CCRI), Multan, Pakistan, and released in 2005 for general cultivation as a part of investigations oriented toward evolving high‐yielding cotton cultivars that are resistant to the cotton leaf curl virus disease (CLCuD). The cultivar was developed through crossing CIM‐425 with 755‐6/93. CIM‐496 was tested in multiple trials conducted by various public agencies, as well as by CCRI Multan. In varietal trials conducted for three successive normal cotton‐growing seasons (2000–2002) at three different sites, CIM‐496 outyielded significantly all the standard varieties included in the present study. In zonal trials arranged at 26 different sites, the seed cotton yield (SCY) of CIM‐496 was 11.1% and 9.8% more than checks ‘CIM‐473’ and ‘CIM‐499’, respectively. In the National Coordinated Varietal Trial (NCVT), CIM‐496 produced more SCY than the standards for two consecutive years (2003 and 2004). CIM‐496 is resistant to the Multan strain of CLCuD and also possesses a higher lint percentage compared with the existing commercial varieties. The commercial cultivation of this cultivar has substantially contributed in sustaining cotton production in Pakistan and can also be used as valuable genetic resource in future cotton breeding programs.