TY - JOUR ID - TI - Application of Probit Analysis in Studying Allelopathy Phenomenon AU - Awadallah B. Dafaallah1* AU - Hana Abass Hussein1 AU - Abdelrahim B. Hamid2 PY - 2020 VL - 61 IS - 6 SP - 1265 EP - 1274 JO - Iraqi Journal of Science المجلة العراقية للعلوم SN - 00672904 23121637 AB - Probit analysis is a type of regression used to analyze the relationship between a stimulus and the quantal response. Allelopathy refers to direct or indirect negative or positive effects of one plant on another through the release of chemical compounds into the environment. This study was carried out to apply probit analysis in investigating the allelopathic effects of the leaves aqueous extracts of apple of Sodom [Calotropis procera (Aiton) W.T.] on the inhibition of seed germination of African rattlebox (Crotalaria saltiana Andr.). Laboratory experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan, in season 2014/15. Ten concentrations (2.3, 4.6, 7.0, 9.3, 11.6, 13.9, 16.2, 18.5, 20.8 and 23.2 g/l) of leaves aqueous extract of apple of Sodom were prepared from a stock solution (50 g / l). A control with sterilized-distilled water was included for comparison. Treatments were arranged in completely randomized design with four replicates. The seeds were examined for inhibition in germination at three days after initial germination. Collected data were transformed using Abbott’s formula and subjected to probit analysis procedure (P  0.5). The results showed that the leaves aqueous extract of apple of Sadom had allelopathic on seed germination of African rattlebox with a direct positive relationship between concentration (g/l) and inhibition (%). Also, the data indicated that the plotting of corrected inhibition (%) against concentration (%) formed a sigmoid curve. Probit analysis transformed the sigmoid concentration-response curve to a straight line. Hence, the LC25 (2.16 g/l), LC50 (8.55 g/l) and LC75 (33.88 g/l) were accurately estimated. It is concluded that probit analysis is an appropriate procedure to study the allelopathy phenomenon.

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