Kijoji Abubakary A, Nchimbi-Msolla Susan, Kanyeka Zakaria L, Klassen Stephen P, Serraj Rachid, Henry Amelia
Sokoine University of Agriculture, Department of Crop Science and Production, PO Box 3005, Morogoro, Tanzania.
International Rice Research Institute, Southern and East Africa Regional Office, Box 33581, Dar es Salaam, Tanzania.
Funct Plant Biol. 2012 Feb;40(1):54-66. doi: 10.1071/FP12163.
Drought is a major constraint to rainfed rice production in some parts of sub Saharan Africa (SSA) because of irregular and low rainfall. Improving root water uptake during progressive soil drying could contribute to terminal drought stress resistance. Two lysimeter experiments were conducted using 200 introgression lines (ILs) derived from Oryza sativa L.×Oryza glaberrima Steud. crosses (IR64/RAM54 and IR64/RAM90) to characterise water uptake and root traits under progressive soil drying and to assess genetic differences among these lines in relation to drought stress. The lysimeter facility setup and protocols for simultaneous monitoring of water uptake rates and leaf area are described. Significant genetic variability for water uptake and root traits among the ILs was observed under drought stress. Water uptake in the drought stress treatments was correlated with root length density (RLD) and root dry matter (RDM) at lower soil depths. The highest RLD values at depth were observed among the RAM90 ILs and genetic differences were observed between RAM90 and RAM54 populations, implying that accession RAM90 could be used as a source for improving drought avoidance in lowland rice. The ILs with greater water uptake identified in this study will be used in future research for improving drought resistance of rice in SSA.
在撒哈拉以南非洲（SSA）的一些地区，干旱是雨养水稻生产的主要限制因素，原因是降雨不规则且降雨量少。在土壤逐渐变干的过程中提高根系对水分的吸收，有助于增强对终末期干旱胁迫的抗性。利用200个源自亚洲栽培稻（Oryza sativa L.）×光稃稻（Oryza glaberrima Steud.）杂交组合（IR64/RAM54和IR64/RAM90）的渗入系进行了两项蒸渗仪试验，以表征在土壤逐渐变干条件下的水分吸收和根系性状，并评估这些品系在干旱胁迫方面的遗传差异。描述了用于同时监测水分吸收率和叶面积的蒸渗仪设施设置及方案。在干旱胁迫下，观察到渗入系之间在水分吸收和根系性状方面存在显著的遗传变异。干旱胁迫处理中的水分吸收与较低土壤深度处的根长密度（RLD）和根干物质（RDM）相关。在RAM90渗入系中观察到深度处的RLD值最高，并且在RAM90和RAM54群体之间观察到遗传差异，这意味着材料RAM90可作为提高低地水稻避旱性的来源。本研究中鉴定出的水分吸收能力更强的渗入系将用于未来提高SSA水稻抗旱性的研究。
