Esteves Nieves, Marilis

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    Determinación de los coeficientes genéticos en maíz para ser utilizados en el modelo CERES-Maize
    (2007) Esteves Nieves, Marilis; Román Paoli, Elvin; College of Agricultural Sciences; Armstrong, Arístides; Muñoz, Miguel A.; Department of Crops and Agro-Environmental Sciences; Avilés, Lucas
    An investigation was conducted in the Agricultural Experimental Station at Lajas, Puerto Rico using crop models to determine maize physiological performance. The objective of this investigation is to determine the genetic coefficients of three varieties of maize; Mayorbela (M), Diente de Caballo (DC), Chulo (Ch) and a hybrid improved for Bacillus thuringiencis (Bt). Four of the most important genetic coefficients for maize were determined; the juvenile phase of plant (P1), growth of the grain from thermal time from silking to physiological maturity (P5), potential number of grains per cob (G2) and the linear dry matter accumulation in grain (Kernel/cob) (G3). The investigation is composed of two experiments conducted on 2004 and 2005. CERES-Maize was validated utilizing published data for the same varieties evaluated in the field using genetics coefficients estimated in Lajas during 2004 and 2005. The statistic analyses showed that M produced the highest yield on 2004 with 4,184 kg/ha. While the Bt hybrid obtained the highest number of kernel/cob with 616. The estimated values for P1 were 219, 253, 252 and 362 heat units for Bt, M, DC, and Ch, respectively. Estimated P5 values corresponded to 660, 720, 673, and 395 heat units for Bt, M, DC, and Ch, respectively. The G3 values obtained were 7.7, 6.7, 6.2 and 3.5 mg/day for Bt, M, DC and Ch, respectively. No significant differences were found for leaf area and biomass accumulation. For the 2005 experiment, the Bt hybrid obtained the highest yield with 3,845 kg/ha and highest kernel number with 590 kernel/cob. No significant differences were found for the number of kernel/cob for M, DC, Ch and Bt hybrid. G3 values were 7.7, 6.7 5.9, and 5.7 mg/day, for DC, Bt, M, and Ch, respectively. The P5 values were similar than those published for maize varieties with, 756, 755, 795, and 777 heat units for Bt, M, DC and Ch, respectively. The values of P1 were greater to those of year 2004. For 2005, P1 estimates were 352 for Bt, 422 for M, 479 for DC and 405 for Ch. Similar than 2004, no significant differences were found for leaf area and the biomass. The variables validated were leaf area index, biomass, kernel number/cob, total leaf number, day of tassel initiation, physiological maturity date and yield. CERES-Maize did not predict yield accurately. In some cases the model overestimates simulated yields around 70% and other underestimates it about 30%.