适度水分胁迫下基因型与土壤水分互作对甘蔗生物量的影响

Effect of Genotype and Soil Moisture Interaction on Sugarcane Biomass Under Moderate Water Stress

【目的】研究甘蔗基因型与土壤水分条件对甘蔗生物量的影响与互作效应,为甘蔗抗旱育种等相关研究提供依据。【方法】在适度水分胁迫条件下,对9份不同基因型甘蔗种质开展水分梯度胁迫桶栽试验,测定并分析生物量、水分利用效率(WUE)、叶片叶绿素相对含量(SPAD)、叶面积、根冠比等指标。【结果】甘蔗生物量与用水量呈极显著正相关,相关系数达0.947,不同基因型甘蔗种质间的生物量及WUE均达到极显著水平(P<0.001);友巴受旱后生物量降幅最大,达59.8%;2份割手密种质表现出较高的WUE,分别达6.97和6.84 g/L;水分胁迫下的根冠比显著高于灌溉(P=0.042);SPAD值与生物量呈极显著正相关,相关系数为0.476,随着水分胁迫程度的逐渐加剧,其均值由46.4显著降至33.9。从S2阶段开始,灌溉和水分胁迫(土壤体积含水量≤80%)下,SPAD值广义遗传率均大于0.5。【结论】甘蔗在水分胁迫下其生物量分配发生改变,光合产物的积累由地上部分向地下部分转移,通过改变根冠比以适应水分胁迫;基因型与水分处理对甘蔗生物量和水分利用效率的互作效应均不显著(P值分别为0.088和0.410),生物量和WUE的变异主要来源于基因型差异;不同基因型对水分胁迫的响应趋于一致,受到水分胁迫后,生物量普遍降低,WUE则无显著差异;SPAD可作为耐旱评价指标应用于早期选择育种实践及种质资源筛选。

【Objective】This paper aimed to illuminate the interaction effects of genotype and soil moisture on sugarcane biomass and provide foundation for sugarcane breeding on drought resistance. 【Method】Under the condition of moderate water stress,a pot experiment of different drought levels was carried out on nine sugarcane germplasm clones. The main traits including biomass,water use efficiency（ WUE）,leaf chlorophyll relative content（ SPAD）,leaf area and root shoot ratio were studied.【Result】Firstly,the biomass was significantly positive correlation with water amount and the correlation coefficient was 0. 947,and the difference of biomass and WUE between differently genotypes of sugarcane reached extremely significant level（ P 0. 001）. Secondly,the clone of Uba had the largest loss of biomass due to drought and two clones of Saccharum Spontaneum performed higher WUE levels with 6. 97 and 6. 84 g/L respectively. Thirdly,the root-shoot ratio of sugarcane germplasms under water stress was significantly higher than that of irrigation（ P = 0. 042）; SPAD value was extremely significant positive correlation with biomass,and the correlation coefficient was 0. 476,and its mean value significant fell to 33. 9 from 46. 4 along with the increasing degree of water stress. Fourthly,the broad-sense heritability of SPAD were greater than 0. 5 since Step 2,both in irrigation and water stress treatments（ soil volumetric water content of 80 % or less）.【Conclusion】Under water stress,sugarcane germplasms tended to change the biomass partitioning ratio by increasing the transfer of photosynthetic products from the ground to the underground part,in other words to adapt water stress by changing the root-shoot ratio. The responses of different genotypes on water stress generally showed consistent trends of biomass reduction,but the WUE was no significant difference. The trait of SPAD could be used as one of drought evaluation indexes for selecting elite clone from sugarcane germplasms in early stage of breeding programs.