Analyses of statistical transformations of row data describing free proline concentration in sugar beet exposed to drought

Abstract

Eleven sugar beet genotypes were tested for their capacity to tolerate drought. Plants were grown in semi-controlled conditions, in the greenhouse, and watered daily. After 90 days, water deficit was imposed by the cessation of watering, while the control plants continued to be watered up to 80% of FWC. Five days later concentration of free proline in leaves was determined. Analysis was done in three replications. Statistical analysis was performed using STATISTICA 9.0, Minitab 15, and R2.11.1. Differences between genotypes were statistically processed by Duncan test. Because of nonormality of the data distribution and heterogeneity of variances in different groups, two types of transformations of row data were applied. For this type of data more appropriate in eliminating nonormality was Johnson transformation, as opposed to Box-Cox. Based on the both transformations it may be concluded that in all genotypes except for 10, concentration of free proline differs significantly between treatment (drought) and the control.

Analizirana je tolerantnost 11 genotipova šećerne repe prema nedostatku vode. Biljke su gajene u polukontrolisanim uslovima, u stakleniku, na supstratu koji je bio mešavina zemlje i peska, pri čemu su biljke svakodnevno zalivane. Posle 90 dana, vodni deficit je izazvan prestankom zalivanja, dok su biljke kontrolne grupe i dalje zalivane, do 80% PVK. Pet dana kasnije utvrđena je, u tri ponavljanja, koncentracija slobodnog prolina u listovima. Statistička analiza je izvršena korišćenjem programa Statistica 9.0, Minitab 15 i R2.11.1. Zbog velike varijabilnosti podataka i odstupanja od normalne raspodele analiziran je uticaj različitih transformacija eksperimentalnih podataka na konačan zaključak. Razlike između aritmetičkih sredina poređene su primenom Dankanovog testa. Na osnovu obe primenjene transformacije može se zaključiti da se kod svih genotipova, izuzev genotipa 10, koncentracija slobodnog prolina u listovima značajno razlikuje između biljaka izloženih suši i kontrole.