Abstract

Drought is the major abiotic stress constraining the production of maize (Zea maysL.) in the arid and semi-arid areas. Recombinant inbred lines (RILs) with improved performance from the 6th selection cycles were evaluated against drought stress at early growth stages and genetic distance was determined through random amplified polymorphic DNA (RAPD) primers. Significant variation was observed in the rate of water loss (RWL) at 30, 90 and 150 min after excision, relative water content (RWC) and membrane stability among the RILs. In comparison with check variety Azam, 7 RILs maintained a low RWL, 2 had higher RWC and 6 RILs had higher membrane stability, thus showing a higher degree of adaptation to drought stress. The preliminary results showed polymorphism among the drought sensitive and tolerant RILs. The RILs were clustered into three groups on the basis of amplification pattern obtained with 60 RAPD markers. Variation in the genetic makeup of the tolerant RILs was evident from their clustering in different groups, though most were clustered in group III. Furthermore, one RAPD marker could identify maize genotypes, maintaining low RWL from the excised leaves. We are in the process of sequencing the amplified product of this primer and transforming it into sequence characterized amplified region (SCAR) markers for a more reliable marker assisted selection.

Key words: Maize recombinant inbred lines (RILs), drought, physiological markers, random amplified polymorphic DNA (RAPD).