Pankaj Rathore

Impact of Harvest-aid Defoliants on Yield of American Cotton and Their Monetary Evaluation

Field experiments were conducted during Kharif 2012 and 2013 to determine the effect of two harvest-aid defoliants i.e Dropp ultra® and Ethrel, their application rates and time of application on three American cotton cultivars. Pooled data revealed significantly higher seed cotton yield for Bt hybrids MRC7361BGII (3055.2kg/ha) and MRC7017BGII (2913.0 kg/ha) as compared to non Bt variety F1861 (2346.0 kg/ha). Among tested defoliants, Dropp ultra® @200ml/ha resulted in better SCY, lint and seed yield. This yield enhancement in case of Dropp ultra® @ 200 ml/ha further lead to significantly better net returns (? 85373/ha) and B: C ratio (2.31) over other treatments. Application of defoliants at 150DAS resulted in significantly improved net returns (? 79288/ha) as compared to earlier application (? 73632/ha) at 140 DAS. Improved water productivity and fertilizer use efficiency coupled with better B: C ratio for Dropp ultra® @ 200 ml/ha at 150 DAS clearly indicated its superiority among all treatments. Therefore Bt hybrids seems to be superior over the non Bt varieties and application of ethrel@2000ppm or dropp ultra® @ 200 ml/ha at 150 DAS should be adopted as useful production practice for enhancing cotton yield under semi-arid conditions of north-western India.

Selection of housekeeping genes and demonstration of RNAi in cotton leafhopper, Amrasca biguttula biguttula (Ishida)

Amrasca biguttula biguttula (Ishida) commonly known as cotton leafhopper is a severe pest of cotton and okra. Not much is known on this insect at molecular level due to lack of genomic and transcriptomic data. To prepare for functional genomic studies in this insect, we evaluated 15 common housekeeping genes (Tub, B-Tub, EF alpha, GADPH, UbiCF, RP13, Ubiq, G3PD, VATPase, Actin, 18s, 28s, TATA, ETF, SOD and Cytolytic actin) during different developmental stages and under starvation stress. We selected early (1st and 2nd), late (3rd and 4th) stage nymphs and adults for identification of stable housekeeping genes using geNorm, NormFinder, BestKeeper and RefFinder software. Based on the different algorithms, RP13 and VATPase are identified as the most suitable reference genes for quantification of gene expression by reverse transcriptase quantitative PCR (RT-qPCR). Based on RefFinder which comprehended the results of three algorithms, RP13 in adults, Tubulin (Tub) in late nymphs, 28S in early nymph and UbiCF under starvation stress were identified as the most stable genes. We also developed methods for feeding double-stranded RNA (dsRNA) incorporated in the diet. Feeding dsRNA targeting Snf7, IAP, AQP1, and VATPase caused 56.17–77.12% knockdown of targeted genes compared to control and 16 to 48% mortality of treated insects when compared to control.

Reference Gene Selection in Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) and Their Normalization Impact on Gene Expression in RNAi Studies

Abstract Phenacoccus solenopsis, the cotton mealybug (Hemiptera: Pseudococcidae), is one of the major cotton pests in India. Scanty information is available on molecular studies in this insect due to limited genomic or transcriptomic sequence data. With advancement in sequencing technology, enormous genomic and sequencing data are being generated, and RNAi studies are being undertaken in insects, which require reverse transcription quantitative polymerase chain reaction evaluation. These gene expression studies require normalization of mRNA levels with reference genes to account for sample variability. To supplement the molecular studies in this insect, candidate reference genes were identified and evaluated for their expression stability across various developmental stages and starvation stress. Fourteen candidate reference genes including several commonly used ones were investigated across five different stages and under starvation stress using four different statistical algorithms (NormFinder, genNorm, BestKeeper, and RefFinder). Based on this analysis, GST (third, fourth, and adult stage), Actin (Crawler, second instar), TFIID (starvation stress), SDHA, and 28s were identified as best reference genes for expression studies in mealybug.

Information Communication Technology for Extension: A Mobile Phone Based Voice Call System for Dissemination of Cotton Production Technologies

ABSTRACT Dissemination of newer crop production technologies among growers is the major bottleneck in the existing extension system. This study proposes an innovative method for dissemination of cotton cultivation technologies through mobile phones. The voice advisories on different aspects of cotton cultivation were sent to mobile phones of growers, as and when required in the field. Feedback from growers revealed it as a highly acceptable extension technique, which helped them to make crucial time-specific decisions for crop management. The system has the potential to reach and benefit each and every grower at a very low cost compared to conventional training and visit extension system.

Study of genotype x environment interactions and stability among diverse Gossypium arboreum L. genotypes for yield and related traits under North Western Plains

The present investigation was undertaken with an objective to determine the effect of genotype × environment (GE) interactions and stability on Gossypium arboreum genotypes belonging to different part of country for seed cotton yield and related traits. Seventeen Asiatic cotton genotypes were evaluated in randomized block design at Ludhiana, for two years (2010 and 2011) and at Faridkot for one year (2010). The significant genotypes, environments, genotype × environment interactions were observed for all traits. Stability parameters revealed LD694 and LD902 were most stable and significantly outperforming for most of the traits except halo length where DLsa1001 was ahead. Genotypes developed at Punjab were found to be more stable for most of the traits whereas genotypes from other centers can be used as germplasm for pre-breeding programmes.

Development and characterization of an interspecific Gossypium hirsutum x Gossypium armourianum hybrid

Interspecific hybrid between Gossypium hirsutum (AADD) cv. F 1861 and G. armourianum (DD) Acc. PAU 1 was generated and characterized along with parents at morphological and molecular levels. Female parent (F 1861) had erect growth habit, cream petals, palmate leaves, green stem, cream anthers, hairy stem and leaves; whereas male parent (PAU 1) had spreading growth habit, yellow petals, cordate leaves, reddish green stem, yellow anthers and glabrous plant body. The growth habit, petal colour, leaf shape and size of interspecific F1 hybrid were intermediate. Plant stem colour and hairiness, leaf pubescence and anther colour of G. armourianum Acc. PAU 1 were observed to be dominant as hybrid fully resembled Acc. PAU 1 for these characters. Petal spot was absent in F 1861 and present in PAU 1as well as hybrid. Variable expression of petal spot, anther colour and filament colour was observed in F1. The interspecific F1 hybrid was male-sterile. Significant differences were observed between the pollen size of parents as well as parents and their hybrid. Of the 33 SSR markers polymorphic between the parents, 8 markers unambiguously confirmed the hybrid status of interspecific hybrid. This hybrid may serve as a useful genetic resource for the transfer of cotton leaf curl disease resistance to American cotton.

Effect of different defoliants and their rate and time of application on American cotton cultivars under semi-arid conditions of north-western India

Field studies were conducted to determine the effect of different defoliants i. e. Dropp ultra® and Ethrel (ethefon), their rates and time of application (140 and 150 DAS) to influence earliness and yield in three cotton cultivars. MRC 7361 BGII (3171.8 kg/ha) and MRC 7017 BGII (3083.3 kg/ha) gave significantly higher yield as compared to F 1861 (2454.9 kg/ha) due to better boll retention, boll weight and sympods. Dropp ultra® @ 200 ml/ha recorded significantly highest yield (3111.6 kg/ha) followed by Ethrel @ 2000 ppm (2948.3 kg/ha) and control (2878.9 kg/ha), while statistically least yield (2674.5 kg/ha) was observed with Dropp ultra® @ 225 ml/ha. Defoliants applied at 150 days after sowing (DAS) resulted in significantly higher yield (3017.7 kg/ha) as compared to early application at 140 DAS (2789.0 kg/ha) owing to significantly improved boll retention and better boll weight. Data indicated that Dropp ultra® @ 200 ml/ha had potential to promote crop earliness, better boll retention by keeping vegetative and reproductive growth in harmony to enhance seed cotton yield.