The Tolerance of Photosynthesis of Some Maize Cultivars (Zea mays L.) to Waterlogging at Different Stages of Growth

The tolerance of plants to waterlogging can be ascertained by identifying the characteristics of morphology, anatomy, and physiology of plants. As yet little is known about the photosynthetic characteristics of many cultivars of maize in Indonesia when waterlogged at various stages of growth. This research aimed to determine the photosynthesis tolerance of some maize cultivars to inundation that occurred at different stages of growth. The factorial completely randomized block design with two factors and three replications was used. The first factor consisted of nine maize cultivars, i.e. Bisi 2, Pioneer 21, Gumarang, Bisma, Sukmaraga, Srikandi Kuning 1, Bima 2, Bima 4, and Bima 5. The second was waterlogged conditions at different stages of growth i.e. the vegetative phase (leaved-four stage- - V4 stage), the early phase of reproduction (silk phase - R1 stage), and the middle phase of reproduction (milk stage - R3 stage), and no waterlogging as the control. During the period of waterlogging, the water level of 5 cm was maintained for 10 days. The results showed that no interaction effect between maize cultivars and waterlogging conditions to almost all photosynthesis variable except stomatal aperture. Ten days of waterlogging at different stages of growth affected photosynthesis by decreasing the chlorophyll content (a, b and total), photosynthetic rate, and the stomatal aperture width. The R1 stage was the stage of growth sensitive to photosynthesis when waterlogged. Bisma cultivar was the maize cultivar that was not tolerant to waterlogging stress at the V4 stage and Gumarang was not tolerant at the R3 stage. It showed a low rate of photosynthesis.  At the R1 stage, Bima 5 and Bima 2 cultivars were the maize cultivars that were tolerant to waterlogging stress, while at the R3 stage all cultivars were tolerant except Gumarang was not. Therefore Bima 5 and Bima 2 cultivars can be recommended to be planted in the swampy areas.