Browsing by Author "Aikpokpodion, P.O."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Evaluation of resistance in selected cocoa genotypes to the brown cocoa mirid, Sahlbergella singularis Haglund in Nigeria
    (2009) Eskes, A.B.; Aikpokpodion, P.O.; Okelana, F.A.; Omoloye, A.A.; Anikwe, J.C.
    The use of host-plant resistance is the most economic and ecologically sound option for the control of the most important insect pest of cocoa, Sahlbergella singularis leaving no deleterious side effects on the produce and the environment. 44 genotypes comprising 24 hybrids and 20 clones were assessed for antixenosis whereas 25 and 28 genotypes were tested for antibiosis and tolerance, respectively. The brown cocoa mirids showed significant non-preference for genotypes T65/7xT57/22, T65/7xT9/15, P7xPa150, T53/5xN38, T53/5xT12/11, T65/35xT30/13, F3 Amazon, T86/2xT16/17, T65/7xT53/8, T86/ 2xT65/35, T82/27xT16/17, T9/15, T12/5, T30/13, C77, T53/8, T53/5, EET59, Pa150, UF 676, Amaz15-15, BE 10, SPEC54 and Pa107. Mirid survival (antibiosis) was lowest in EET59 (28.7%) while it ranged from 52.2 to 67.8% in genotypes BE10, Amaz15-15, SPEC54, UF 676, P7xPa150, and Pa107. The indigenous clone N38 had the highest number of lesions of 12.2 in the field while EET59, IFC-5, Playa Alta, BE10, Amaz15-15 and SPEC54 had mirid lesions of 2.7, 3.3, 5.2, 5.3, 5.5 and 5.5; respectively. However, in terms of recovery from mirid damage and dieback progression which were important parameters assessed in tolerance, Clones ICS1, EET59, BE 10, Amaz15-15, SPEC54 and Pa 102 showed highest rate of recovery from mirid damage and lowest dieback progression. Clones UF 676, C77, Pa150 and F3 Amazon also showed moderate recovery from mirid damage with mean scores of 1.2, 2.3, 1.6, 1.4, 1.7, 1.4 and 1.5, respectively. UF 676, C77, Pa150 and F3 Amazon performed moderately well in terms of tolerance. Some of these genotypes such as BE10, Amaz15-15, SPEC54, UF 676, P7xPa150, and Pa107 were very consistent in all mechanisms of resistance tested and therefore adjudged as resistant cocoa genotypes.
  • Thumbnail Image
    Item
    Evaluation of the susceptibility of local cocoa germplasms in Nigeria to Phytophthora pod rot disease using the leaf discs technique
    (WFL Publisher, 2006) Otuonye, A.H.; Adeoti, A.Y.A.; Agbeniyi, S.O.; Aikpokpodion, P.O.; Enikomehin, O.; Popoola, T.O.
    The Phytophthora pod rot disease constitutes a major threat to cocoa cultivation in all cocoa-growing regions worldwide. It is one of the most important diseases limiting the attainment of genetic yield potential of this tree crop. Though available, chemical control methods are often expensive and beyond the reach of peasant farmers that produce more than 95% of Nigeria crop. Also, the limited knowledge of rational chemical application among rural farmers and the adverse effect on the environment makes it an unfriendly approach. Breeding commercially viable resistant cacao genotypes have been advocated to be the most durable control approach against the Phytophthora pod rot. Towards achieving this objective, promising cacao materials were selected from the gene pool in Cocoa Research Institute of Nigeria (CRIN) Headquarters, Ibadan. Screening of these eight selected cocoa clones with four isolates of Phytophthora megakarya of known aggressiveness in combination-NGRI4, using the leaf discs inoculation method at standard inoculum concentration of zoospores of 3 x 105 ml-1 was carried out. Results showed that T12/5 was resistant, while clones T17/11 and T86/2 are moderately resistant. The other clones, T85/5, T85/45 and T20/11, were moderately susceptible. It is therefore suggested that clone T12/5 be integrated into the resistance breeding effort against Phytophthora pod rot.