بررسی برهمکنش تنش سرما و خشکی بر تغییرات شاخص کلروفیل، محتوای نسبی آب برگ، نشت الکترولیت و عملکرد دانه در سه رقم هیبرید ذرت دانه ای

Chlorophyll, RWC, electrolyte leakage and seed performance of three maize hybrid varieties under draught and chilling stress conditions were examined.  The experiment was carried out in split-split plots using random completely blocks design with three replications in 2013-2014 in research farm and greenhouse Mashhad University of Ferdowsi, Agronomy Faculty. The main plot was chilling stress at two levels (present and absence of chilling stress); the subplot were drought stress at three levels (100% irritation, 75% irritation, and 50% irritation); sub-subplot was maize hybrid variety (single cross 704, single cross 400, and single cross 260).  Results showed that stress conditions affected SPAD so that draught stress declined RWC and stability of cytoplasm membrane. The highest RWC and stability of cytoplasmic membrane were seen in single cross 260 and 400.  Mutual effects of the treatments showed that the chilling and 100% irritation single cross 704 treatments had the highest SPAD. In addition, SPAD, RWC, and electrolyte leakage at the end of season decreased relative to the emergence time of male inflorescence. In presence of chilling and draught stresses, single cross 400 had higher performance comparing with the two other hybrids. This, in turn, indicates better performance of such treatment comparing with the other hybrids.