Role of Canopy Coverage in Water Use Efficiency of Lowland Rice in Early Growth Period in Semi-Arid Region
Role of Canopy Coverage in Water Use Efficiency of Lowland Rice in Early Growth Period in Semi-Arid Region
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DOI：
10.1626/pps.16.12
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发表时间：
2013-01
影响因子：
2.5
通讯作者：
Tetsuji Suzuki;T. Ohta;Yasuhiro Izumi;L. Kanyomeka;O. Mwandemele;J. Sakagami;K. Yamane;M. Iijima
中科院分区：
文献类型：
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作者：
Tetsuji Suzuki;T. Ohta;Yasuhiro Izumi;L. Kanyomeka;O. Mwandemele;J. Sakagami;K. Yamane;M. Iijima
摘要水稻品种与种植制度的合理组合，使水分利用效率（WUE）最大化，可以提高低地水稻的产量。在水稻生长初期，大量的水分被蒸发所消耗，特别是在半干旱地区，可以通过冠层覆盖来减少水分的消耗。因此，我们评估了冠层覆盖度在半干旱地区水稻生育前期水分利用效率中的作用。在纳米比亚进行了盆栽试验，研究了小麦WUE的基因型和种间差异，并进行了盆栽试验和田间试验，研究了种植密度对WUE的影响。虽然种间差异不显著，但平均WUE的大小顺序为水稻>光叶稻>包括非洲新稻在内的种间后代。相反，WUE在基因型水平上存在显著差异。WAB 1159 -2-12-11-5-1和WITA 2等高分蘖基因型表现出较高的水分利用效率。水分利用效率与分蘖数呈显著正相关（R2 = 0.453），种植密度越大，水分利用效率越高。气孔导度与水分利用效率相关不显著（R2 = 0.081）。因此，受分蘖数和种植密度影响的物理条件对水分利用效率的影响大于气孔导度等生理特性。植被覆盖对地表水蒸发的抑制作用是显著的，可能有助于提高水分利用效率。为了提高半干旱地区的水分利用效率，建议增加林冠覆盖度和种植密度。
Abstract An appropriate combination of rice cultivar and cropping system that maximizes water use efficiency (WUE) may improve yield of rainfed lowland rice. In the paddy field, a large amount of water is consumed by evaporation during the early growth period, and it can be reduced by canopy coverage especially in semi-arid regions. Therefore, we evaluated the role of canopy coverage in WUE of rice in the early growth period in semi-arid region. A pot experiment was conducted in Namibia to investigate the genotypic and species difference in WUE, and another pot and a field experiment were conducted to investigate the effects of planting density on WUE. Although no significant difference was observed among species, the mean WUE was in the decreasing order of Oryza sativa, and Oryza glaberrima followed by the interspecific progenies including NERICA. In contrast, there was a significant difference in WUE at the genotypic level. Highly tillering genotypes such as WAB1159-2-12-11-5-1 and WITA 2 showed a high WUE. Furthermore, WUE was significantly correlated with the number of tillers (R2 = 0.453), and higher planting density resulted in a higher WUE. In contrast, stomatal conductance had no significant correlation with WUE (R2 = 0.081). Thus, the physical conditions affected by number of tillers and planting density had greater impacts on WUE than physiological characteristics such as stomatal conductance. The suppression of surface water evaporation by coverage was significant, probably contributing to WUE improvement. To increase WUE in semi-arid regions, we recommend the increase of canopy coverage and higher planting density.