ISHS Acta Horticulturae 593: IV International Symposium on Models for Plant Growth and Control in Greenhouses: Modeling for the 21st Century - Agronomic and Greenhouse Crop Models
EFFECTS OF TEMPERATURE AND PHOTOPERIOD ON DEVELOPMENT RATES OF NINE SOYBEAN VARIETIES IN THE MISSISSIPPI VALLEY |
| Authors: | V.R. Reddy, L.B. Pachepsky, F.D. Whisler |
| Keywords: | Ontogeny, reproductive stage, solstice, simulation, planting |
| Abstract:
Time to flowering in soybeans Glycine max (L.) Merr. is affected by environmental conditions, temperature and photoperiod being the leading environmental factors. Most of available experimental data in the Mississippi Valley indicate mid- and late spring plantings. Planting dates in soybean crops vary significantly, and late plantings are not uncommon, especially in years with extreme spring weather events. The development rates of soybean are cultivar specific but also affected by temperature and photoperiod. The objective of this study was to quantify differences in development rates in field soybean crops encountering different daylength patterns. Nine soybean varieties were planted on three different dates in two soil types. Each treatment had five replications. Phenological observations and their quantitative analysis confirmed the earlier proposed hypothesis by Acock et al. (1997) that the daily increment in reproductive stage could be simulated as a linear function of photoperiod with slopes of these linear functions different before and after solstice. | |
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