Evaluation of non-Linear regression models to predict jointing rate of wheat cultivars in response to temperature and Photoperiod

Subject Areas : Journal of Plant Ecophysiology

محمد حسن پناهی ¹ , افشین سلطانی ² , ابراهیم زینلی ³ , مهدی کلاته عربی ⁴ , علیرضا نه بندانی ⁵

1 - دانش آموخنه کارشناسی ارشد دانشگاه علوم کشاورزی و منابع طبیعی گرگان
2 - استاد گروه زراعت دانشگاه علوم کشاورزی و منابع طبیعی گرگان
3 - دانشیار گروه زراعت دانشگاه علوم کشاورزی و منابع طبیعی گرگان
4 - استادیار و عضو هیئت علمی مرکز تحقیقات کشاورزی و منابع طبیعی استان گلستان
5 - دانشگاه کشاورزی و منابع طبیعی گرگان

Received: 2015-03-01 Accepted : 2015-07-05 Published : 2016-09-01

Keywords: Modeling, : biological day, critical photoperiod, photoperiod sensitivity coefficient,

Abstract :

Accurate prediction of phenological development is important in the wheat)Triticum aestivum(. An important parameters on phenology can be suggest temperature and photoperiod. This study was conducted with 12 sowing dates to quantify response of jointing rate (JOR) to temperature and photoperiod in wheat cultivars. The regression models fitted to JOR against temperature were beta, dent-like and segmented function. Meanwhile, quadratic, negative exponential and segmented models fitted to JOR against photoperiod (these models were used as 9 combined models to describe JOR as a function of photothermal day). The results showed that beta- quaradic function was the best model to describe JOR as a function of both temperature and photoperiod. Using this function, the base, optimum and ceiling temperatures were estimated 4.5, 27.3 and 40 ₒC respectively. Critical photoperiod and photoperiod sensitivity coefficient were estimated 20.02 to 22.69 hour and 0.0109 to 0.0475 respectively. Also biological day for cultivars between emergence to jointing with the beta- quaratic function examin between 25.2 to 31.9 days.The results of this study can be used in crop simulation models.