بررسي تاثير تنش كم آبي و كاربرد سلنيوم بر برخي از خصوصيات زراعي دو رقم سويا

Effect of Drought Stress and Selenium Foliar Application on some Agronomic Characters of Soybean varieties

This experiment was conducted in order to study the effects of water deficit on some physiological characteristics, yield and yield component of two soybean varieties. This experiment was carried out in research fields of Islamic Azad University - Karaj Branch and Tarbiat Moalem University in 2004. In this research possibility of using mannitol for selection of drought stress tolerance soybean varieties during germination were examined. Radical length stability was the main factor for selection. Radical and shoot length and germination evaluated with factorial design based on complete randomized design (CRD) with four replication. First factor was two varieties (Williams and Harour) and second factor was four osmotic potential (0,-4,-8 and -12 bar). Results showed significant differences (%1) between osmotic potential and varieties for radical, shoot length and germination. In field experiment a split split plot design under randomized complete block design (RCBD) with four replication were used. Varieties was factor A (Williams, Harcor) and time of spraying (vegetative growth, beginning of flowering) was factor B and factor C was selenium concentration (Se=0, Sei=16 g/ha and Se2=21g/ha). In field experiment fallowing characters were studied: seed yield, total dry weight, HI, seed 1000 weight, number of pods per plant , number of seeds per pod , content of chlorophyll a, b , relative water content , LAI , SLW , leaf cell membrane stability and antioxidant enzymes activity ( super oxide dismutase , catalase and glutathione peroxides ). Results of field experiments showed That seed yield , total dry weight , seed 1000 weight, number of pods per plant, number of seeds per pod, SLA, SLW and LAI had significant differences but others didnt showed any significant differences. Results of irrigation treatments in combined analysis showed significant differences for all the characters. There was a logical relationship between characters measured in laboratory and some characters measured in field experiment. Williams variety that had longer radical and higher radical length stability indicated better physiological and agronomical characteristics in field. Results of biochemical studies showed that antioxidant enzymes activity increased under drought stress and maximum activity of glutathione peroxides obtained under using 21 g/ha selenium in Williams variety.