IMPACTS OF MOLYBDENUM ON DROUGHT TOLERANCE OF SOME MAIZE (Zea mays L.) CULTIVARS AT SEEDLING STAGE

Drought stress is one of the factors imposing drastic effects on maize growth and productivity. Molybdenum (Mo) has been proved to mitigate the negative effects of drought stress on many crops. This paper presents results of experiments on the effects of Mo on drought tolerance of three maize varieties namely CP333, HN45, and HN68 at seedling stage. There were two experimental formulas: the control group was watered (F I) and the treatment group was sprayed with Mo liquid 0.03% (F II) from sowing to the stage of two true leaves. After that, artificial drought treatment was provided by stopping watering and spraying for 1-day, 3-day, and 5-day. The results show that Mo enhanced drought tolerance of three maize varieties in comparison with the control group. The most drought tolerant line was CP333 with its drought tolerance indices of 3207.10 in F I and 3613.37 in F II, followed by HN45 with 2790.62 in F I and 3213.14 in F II, and the least drought tolerant cultivar was HN68 with the drought tolerance indices of only 2621.79 in F I and 3012.53 in F II. Additionally, Mo was also proved to have a direct effect on the drought tolerance of maize varieties via several indicators such as leaf water content, leaf water retention capacity, leaf transpiration rate, and root weight. The research results serve as a scientific basis for proposals to enhance drought tolerance of some maize cultivars in Vietnam.