Selection of Wet-resistant Silage Corn Hybrids by Variations of Leaf Fluorescence after Excess Water Treatments in Early Growth Stage

Abstract

Two pot experiments were conducted in a phytotron to evaluate and select a wet-resistant silage corn hybrids from 111 corn hybrids (CHs) under simulated heavy rainfall of 100 mm for the 1st day and 50 mm from the 2nd day at the 3rd and 5th leaf stages in experiments 1 and 2, respectively. All CHs were tested under a rainfall of 280 mm for 5 days followed by irrigation treatment that started 38 days after seeding at 21±3 in experiment 1 and 44 days at 24±3 in experiment 2. Physiologically, the value of leaf fluorescence for normal corn growth is above 0.85 and more than 0.75 for re-growth after wilting, while no re-growth when it is lower than 0.70. Thus, measurement of leaf fluorescence at the initial stage of growth after water submersion is considered a useful criterion for the selection of CHs that are resistant to excess water stress. Values of leaf fluorescence (FLU) rapidly decreased after water irrigation in both temperature ranges; however, the recovery speed was faster in the irrigation treatment of 5th than 3rd leaf stage. In conclusion, we recommend that selection criteria of CHs at the early 3rd leaf growth stage with 5 days water treatment should be compared based on overcoming speed of FLU, which is one of useful and non-destructive physiological methods at this 3rd leaf stage compared with 5th leaf stage.