Characterization of vegetative and grain filling periods of winter wheat by stepwise regression procedure, I: Vegetative period

Abstract

Modeling plant growth by mathematical functions is important for understanding plant development and growth. Most of the models of dry matter accumulation in small cereals simulated the period of grain filling while small attention has been devoted to mathematical simulation of vegetative period till anthesis. The aim of this research was to determine the most appropriate polynomial non-linear regression for dry matter accumulation till anthesis in winter wheat. Pobeda, a medium early variety, was used as model genotype for this research. A 5-year field data were analyzed by the forward procedure of stepwise regression. Although the procedure requires the maximum power of the polynomial regression to be used, we suggest using a lower power since it is easier for understanding and explanation and it is taking into account literature sources and biological laws. It can be accepted that quadratic regression model appropriately fits the process of dry matter accumulation till anthesis in winter wheat.

Modelovanje rasta biljke matematičkim funkcijama važno je za razumevanje razvoja i rasta biljaka. Većina modela akumulacije suve materije kod strnih žita simuliraju period nalivanja zrna, dok je malo pažnje posvećeno matematičkoj simulaciji perioda do cvetanja. Cilj ovog istraživanja bio je da se odredi najprikladnija funkcija za simuliranje akumulacije suve materije do cvetanja ozime pšenice hijerarhijskim modelom višestruke regresije (stepwise polynomial regression). U istraživanju je korišćena srednje rana sorta Pobeda. Hijerarhijski model korišćen je za analizu petogodišnjih rezultata. Iako procedura zahteva primenu polinoma sa najvišim odgovarajućim stepenom, predlažemo da se koristi niži stepen, koji ipak adekvatno opisuje proces nakupljanja suve materije do cvetanja. Može se zaključiti da kvadratna regresija opisuje na prihvatljiv način proces nakupljanja suve materije do cvetanja ozime pšenice.