Browsing by Author "Nair, R.V."

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    Analysis of genetic diversity in coconut and its conservation in root (wilt) disease affected areas of Kerala: A community participatory approach
    (2013) Thomas, R.J.; Rajesh, M.K.; Kalavati, S.; Krishnakumar, V.; George, D.J.; Jose, M.; Nair, R.V.
    Root (wilt) disease is a major constraint to coconut production in Kerala State. Conserving ecotypes with resistance or tolerance to the disease on a community basis is essential to sustain coconut production in the root (wilt) disease prevalent areas. Three communities viz., Pathiyoor and Devikulangara (Alappuzha District) and Thodiyoor (Kollam District) were selected and a survey was conducted with the participation of stakeholders, to characterize the local coconut ecotypes. Six ecotypes comprising of four talls and two dwarfs were identified and morphological data revealed that the local Jappanan ecotype closely resembled Evoor Green Tall ecotype. Simple Sequence Repeat (SSR) analysis in 90 selected coconut palms representing the six ecotypes using 14 markers indicated that the observed heterozygosity was higher in tall ecotypes (0.179-0.365) compared to the dwarfs (0.03-0.07). Lower values for observed heterozygosity compared to the expected heterozygosity in tall ecotypes are indications of genetic basis for disease resistance observed in diseasefree mother palms. Molecular characterization helped in identifying diverse coconut ecotypes having application in production of vigorous hybrids. In the dendrogram constructed using nut character data, three of the tall ecotypes (Green Tall, Brown Tall and Brick Red Tall) clustered together whereas Jappanan clustered separately. Mantel s correlation test using the ZT software revealed significant correlation (0.96) between the SSR data and morphological data.
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    Analysis of population structure and genetic relatedness among root (wilt) disease-resistant and susceptible west coast tall coconut palms (Cocos nucifera) using microsatellite markers
    (2011-06) Devakumar, K.; Thomas, R.J.; Nair, R.V.; Augustine Jerard, B.; Rajesh, M.K.; Jacob, P.M.; Jayadev, K.; Parthasarathy, V.A.
    The population structures among the root (wilt) disease-resistant and susceptible coconut palms from 12 locations in the three disease-endemic districts of southern Kerala, were analyzed using nine microsatellite markers. The pair-wise population differentiation estimate (Fs) between the resistant and susceptible populations was 0.021. Two major populations and a subpopulation cluster were identified among the resistant palms. The analysis of genetic relatedness between the resistant mother palms showed that most of the palms located in a single locality shared sib relationship among them. The existence of close genetic relationship among resistant palms from Chengannur, Thiruvalla, Kottayam and Pavukkara localities in Kerala were reported. The results are discussed in terms of breeding strategies for increasing heterozygosity and obtaining the maximum number of disease-resistant seedlings.
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    Analysis of segregating populations of West Coast Tall variety of coconut using microsatellite markers
    (2006) Manimekalai, R.; Rubavathi, V.B.; Thomas Regi, J.; Nair, R.V.; Rajesh, M.K.
    In vitro antagonistic studies with native Trichoderma spp viz., T.viride, T.harzianum & T.hamatum and a bacterial strain of Pseudomonas fluorescens revealed that the mycelial growth of the coconut pathogens viz., Ganoderma applanatum and G.lucidum (basal stem rot pathogens) and Thielaviopsis paradoxa (stem bleeding pathogen) was highly inhibited by T.viride (more then 80%). Pseudomonas fluorescens completely inhibited the growth of both the species of Ganoderma, whereas only 33% inhibition was observed in the growth of T.paradoxa. All the three species ofTrichoderma were found to be very effective in producing specific volatile met.abolites against T.paradoxa. The volatile metabolites of P.fluorescens completely inhibited G.applanatum and Glucidum but non-volatile metabolites were not effective. Application of 50 g of talc formulation of Trichoderma viride or T.harzianum or T.hamatum with combination of5 kg neem cake/palm/year in basins around the palm was found to be effective in the management ofbasal stem rot disease and smearing oftalc powder paste ofTrichoderma viride or T.harzianum or T.hamatum reduced bleeding patches due to stem bleeding disease. Developed a common biointensive "10M package against basal stem rot and stem bleeding diseases.
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    Asexual propagation of cocoa (Theobroma cacao L.)
    (2007-02) Nagabhushanam, S.; Nair, R.V.
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    Breeding for resistance/tolerance to root (wilt) disease
    (2007-02-08) Nair, R.V.; Jacob, P.M.; Koshy, P.K.; Sasikala, M.; Nampoothiri, K.U.K.
    Root wilt is a serious disease of coconut in Kerala. The disease affects 16 million palms and cause an annual loss of 968 million nuts. Involvement of phytoplasma in the etiology of this disease has been established. Breeding for evolving root (wilt) resistant varieties - being the lasting solution for the disease is implemented since 1987. In the heavily diseased tracts, some high yielding west coast tall and chowgate green dwarf palms were found to be resistant and serologically negative under field conditions. Studies indicated that CGD palms were having higher level of resistance to the disease compared to that of other varieties. It has also been reported that CDO X WCT hybrids gave higher yield in spite of contracting the disease. Based on these,observations, the following crosses are made - WCT X WCT (inter-se), WCT (self), WCT X CGD, CGD X WCT, CGD (self/inter-se), CDO (self/inter-se). The present crossing programme includes 63 WCT, 97 CGD and 4 CDO palms in the farmers plots.The 2725 progenies were under planted among heavily infested palms for evaluating their resistance and use them as future mother palms. In the seventh year of planting, WCT (open pollinated) seedlings showed 60%disease incidence where as WCT (self) and WCT (inter-se) showed 45% disease incidence and only 31% in CGD X WCT. Four seed gardens have been established by planting 3371 artificially pollinated seedlings.
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    CGDxWCT hybrid - an ideal planting material for root (wilt) disease endemic areas
    (2007-02-08) Jacob, P.M.; Iyer, R.D.; Nair, R.V.; Nampoothiri, K.U.K.
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    Chowghat Green Dwarf - A suitable variety for the coconut root (wilt) diseased tract
    (2007-02-08) Nair, R.V.; Rajesh, M.G.; Jacob, P.M.
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    Coconut varieties resistant to root (wilt) disease
    (2006-10) Nair, R.V.; Thomas, R.J.; Sunil A. Nair
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    Coconut variety Kalpa Dhenu
    (2009) Niral, V.; Augustine Jerard, B.; Samsudeen, K.; Arunachalam, V.; Kumaran, P.M.; Ratnambal, M.J.; Rao, E.V.V.B.; Filial, R.V.; Satyabalan, K.; Nampoothiri, K.U.K.; Nair, M.K.; Bavappa, K.V.A.; Nair, R.V.; George V. Thomas; Kumar, M.; Meenakshi Ganesan, N.; Arulraj, S.
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    Coconut variety Kalpa Mitra
    (2009) Niral, V.; Augustine Jerard, B.; Samsudeen, K.; Arunachalam, V.; Kumaran, P.M.; Ratnambal, M.J.; Rao, E.V.V.B.; Filial, R.V.; Satyabalan, K.; Nampoothiri, K.U.K.; Nair, M.K.; Bavappa, K.V.A.; Nair, R.V.; George V. Thomas; Bandopadhyay, A.; Ghosh, D.K.; Hore, J.K.; Sarangi, A.; Mitra, S.K.; Chattopadhyay, P.K.; Maity, S.C.; Arulraj, S.
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    Coconut variety Kalpa Pratibha
    (2009-05) Niral, V.; Augustine Jerard, B.; Samsudeen, K.; Arunachalam, V.; Kumaran, P.M.; Ratnambal, M.J.; Rao, E.V.V.B.; Pillai, R.V.; Satyabalan, K.; Nampoothiri, K.U.K.; Nair, M.K.; Bavappa, K.V.A.; Nair, R.V.; George V. Thomas; Reddy, V.S.K.; Goutham, B.; Kalpana, M.; Raghava Rao, D.V.; Nageswarao, M.B.; Srinivasulu, B.; Vaithilingam, R.; Natarajan, C.; Kumar, M.; Meenakshi Ganesan, N.; Nagwekar, D.D.; Arulraj, S.;
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    Comparative drought tolerance of cacao accessions
    (2007-02-08) Balasimha, D.; Rajagopal, V.; Daniel, E.V.; Nair, R.V.; Bhagavan, S.
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    Development of a Dwarf x Tall coconut hybrid 'Kalpa samrudhi'
    (2015-04) Augustine Jerard, B.; Niral, V.; Samsudeen, K.; Nair, R.V.; Jayabose, C.
    An evaluation trial conducted over 28 years on coconut hybrid combinations has resulted in identification of a superior, high yielding Dwarf x Tall hybrid, named as ‘Kalpa Samrudhi’ involving IND 058S as female parent and IND 069S as male parent. The results revealed that the hybrid is better performing over other hybrids and local control with higher fruit yield (117 fruits palm-1 year-1), high copra out turn (25.72 kg palm-1 year-1 or 4.5 t ha-1 year-1 copra) and estimated oil recovery of 3.04 tonnes ha-1 under rainfed conditions of Kerala. The palms of the hybrid are semi tall, take an average of 45 months for initiation of flowering under rainfed conditions, possess good tender nut water quality (TSS 6o Brix) and higher quantity (346 mL per tender nut). The tender nut water has Na content of 35.1 ppm and K content of 2370 ppm. The hybrid recorded 30.27 per cent more nut yield, 66.05 per cent more copra yield and 73.71 per cent more oil yield over another released Dwarf x Tall hybrid ‘Chandra Sankara’. The seedlings of the hybrid are more vigorous, producing higher number of leaves within 12 months, having higher leaf area and dry weight indicating precocity in growth and development. The flowering, morphological and fruit component traits of the hybrid were compared with parental palms. The characteristics of this hybrid and its performance indicate potential to increase the production and productivity of coconut.
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    Development of varieties of coconut (Cocos nucifera L) resistant/tolerant to root(wilt) disease
    (2004-12) Nair, R.V.; Jacob, P.M.; Thomas, R.J.; Sasikala, M.
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    Diversity Conservation and Utilization Strategies in Improvement of Cocoa (Theobroma Cacao L.)
    (2011-01) Elain Apshara, S.; Ananda, K.S.; Nair, R.V.
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    DNA amplification fingerprinting in coconut : protocol optimization and analysis of resistance to root (wilt) disease
    (2005) Jayadev, K.; Rajesh, M.K.; Devakumar, K.; Regi Jacob Thomas; Nair, R.V.; Parthasarathy, V.A.
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    Evaluation and identification of high yielding trees in Nigerian cocoa germplasm
    (2009) Elain Apshara, S.; Bhat, V.R.; Ananda, K.S.; Nair, R.V.; Suma, D.
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    Evaluation of cocoa (Theobroma cacao L.) hybrids
    (2007-02) Bhat, V.R.; Sujata, K.; Ananda, K.S.; Nair, R.V.; Virakthmath, B.C.
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    Evaluation of coconut germplasm for fruit component traits and oil yield
    (2009) Niral, V.; Nair, R.V.; Augustine Jerard, B.; Samsudeen, K.; Ratnambal, M.J.
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    Field resistance of lethal yellowing disease in some coconut varieties in Nigeria
    (2006-10) Odewale, J.O.; Nair, R.V.; Louis Enaberue