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INCIDENCE OF ROOT (WILT) DISEASE IN VARIOUS CROSS COMBINATIONS OF WEST COAST TALL VARIETY OF COCONUT R.V. Nair; P.M. Jacob; M.G. Rajesh; R.J. Thomas
International Coconut Community Journal Vol 19 No 01 (2003): CORD
Publisher : International Coconut Community

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37833/cord.v19i01.369

Abstract

Root (wilt) disease is a very serious disease of coconut in eight southern districts of Kerala, India. A comprehensive breeding programme – the only practical solution for the management of the disease – was started at Central Plantation Crops Research Institute (CPCRI), Kayangulam during 1987. Coconut seedlings, belonging to five cross combinations with WCT viz. WCT (Inter se), West Coast Tall (WCT) (Self), WCT (Mixed Pollen), Chowghat Green Dwarf (CGD) x WCT and WCT (Open Pollinated) were studied for their incidence of root (wilt) disease. All the seedlings were planted during 1992 except CGD x WCT which was planted during 1991. In the absence of a mass screening technique under artificial conditions, assessment of resistance was based on natural infection. The progenies belonging to various cross combinations of WCT x WCT showed significant variability for incidence of root (wilt) disease. Observations, recorded during September 2002, revealed that the incidence of root (wilt) varied from 53.4 to 55.2 % in WCT x WCT crosses whereas CGD x WCT had 64.5 %. Open pollinated seedlings from healthy mother palms contracted 70 % incidence of the disease. The studies showed superiority of artificially pollinated seedlings (full sibs) over the open pollinated seedlings (half sibs) with regard to their susceptibility to the disease.
FIRST RECORD OF THE INCIDENCE OF THE COCONUT MITE, ACERIA (ERIOPHYES) GUERRERONIS KEIFER IN NIGERIA C.I. Aisagbonhi; R.V. Nair; K.O. Kolade
International Coconut Community Journal Vol 20 No 1 (2004): CORD
Publisher : International Coconut Community

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37833/cord.v20i01.377

Abstract

In continuation of the search for the causes of premature nutfall of coconut palms in Nigeria, samples of fresh fallen nuts were examined under the microscope. Coconut palms (Chowghot Dwarf green (Indian), Malayian Dwarf yellow and Malayian Dwarf orange were surveyed between May to August 2003. The button stage nuts and premature nuts that recently fell on the ground were picked and conveyed back to the laboratory. The perianth (calyx ends) of each nut were split opened and examined under the microscope for presence of mites. Aceria(Eriophyes)guerreronis population were assessed per nut. All three ecotypes examined were infested. Preliminary observations indicated a mean mite population of 187.94 + 17.92 per nut sampled.Mealybugs (Pseudococcus sp) and some unidentified mites were also observed. The role of these mites in the incidence of premature nutfall of coconut palms is discussed in this paper.
DNA amplification fingerprinting in coconut: protocol optimization and analysis of resistance to root (wilt) disease K. Jayadev; M.K. Rajesh; K. Devakumar; Regi Jacob Thomas; R.V. Nair; V.A. Parthasarathy
International Coconut Community Journal Vol 21 No 1 (2005): CORD
Publisher : International Coconut Community

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37833/cord.v21i01.396

Abstract

Root (wilt) disease is a serious malady in coconut causing a loss of approximately 968 million nuts a year in India. Integrated management practices are the only suggested methods to reduce its effect to some extent, while the development of resistant varieties will offer a permanent solution for which concrete breeding efforts are required. Considering the long life cycle of coconut, selection of resistant varieties through conventional methods will be time consuming and laborious. Molecular markers offer numerous advantages over markers traditionally used in plant mapping and selective breeding. Here, we present the optimization of PCR conditions for DNA amplification fingerprinting (DAF) of coconut using arbitrary oligonucleotide primers. Three of the primers could detect variations between root (wilt) resistant and susceptible coconut palms. This study constitutes the basis for future efforts to tag the root (wilt) resistant gene(s) in coconut.