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A simulation model of pineapple growth and development (CERES-Pineapple) was developed, using the structure of CERES-Maize and a heat unit model for pineapple inflorescence development. The model is process-oriented and incremented daily. It simulates the effects of planting date, plant population, plant size at planting and at forcing, and weather on pineapple crop growth and development. CERES-Pineapple was calibrated to field data collected from a plant population trial at Kunia, Hawaii, and validated using data from 11 plantings of pineapple grown in Hawaii. The model accurately simulated pineapple growth and development for most Hawaii conditions but underpredicted fruit yields for pineapple grown at high elevations. CERES-Pineapple also provides a frame-work for the conduct of pineapple research and has potential to serve as a decision aid for pineapple farmers.
Centipedegrass [Eremochloa ophiuroides (Munro) Hack] is a native grass of China, and information on soil adaptation ranges, including acid soils, among centipedegrass cultivars is limited. Therefore, objectives of this study were 1) to conduct a preliminary evaluation of relative aluminum tolerance of 48 centipedegrass accessions plus a cultivar, TifBlair, and a common centipedegrass under aluminum (Al) stress (0 and 1500 μM Al) by using a solution culture method; and 2) to determine Al effects on nutrient uptake between resistant-group and sensitive-group accessions among the 50 accessions and cultivars. Differences were found among accessions and cultivars, and the CV of relative root weight, relative shoot weight, and relative total weight were 39.9%, 32.9%, and 33.6%, respectively. After growing 28 days in an acid subsoil, the resistant-group accessions showed much better growth than the sensitive-group accessions. The Al concentrations in roots and shoots of the two groups of accessions were increased under Al treatment, but most absorbed Al remained in roots with greater Al absorption among the sensitive group compared with the resistant group. The concentrations of phosphorus (P), magnesium (Mg), calcium (Ca), and potassium (K) in the two groups were reduced under Al stress with reductions of 59.3%, 54.8%, 47.9%, and 41.3% in shoots and reductions of 8.70%, 52.5%, 43.2%, and 34.4% in roots, respectively. Under Al stress, differences in P, Mg, and Ca concentrations were found between the two groups; however, differences were not found for K. The resistant-group accessions maintained higher concentrations of Mg and Ca than the sensitive group.