5种气候生态型割手密F_1和F_2杂种的耐旱性评价

【目的】干旱是甘蔗生产中重要的逆境因子,严重影响甘蔗产量和品质。甘蔗野生资源割手密具有抗逆性强、宿根性强、适应性广等特点,研究其后代耐旱性,筛选耐旱种质,为培育新型抗旱亲本、实现甘蔗新品种突破提供理论依据。【方法】选取5种生态类型割手密与云瑞系列创新亲本、国外种以及国内种的杂交F_1、F_2代材料共36份,采用温室人工控水胁迫的方法,于甘蔗拔节初期设置正常供水(作对照)、轻度胁迫和重度胁迫3个处理。分别测定3个处理条件下甘蔗叶片质膜透性(plasma membrane permeability,PMP)、丙二醛(malondialdehyde,MDA)、叶绿素(chlorophyll,CHL)、可溶性蛋白(soluble protein,Pr)、脯氨酸(proline,Pro)含量和超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)酶活性7个生理生化指标,利用模糊隶属函数法、聚类分析和灰色关联度分析,综合评价割手密后代在不同程度水分胁迫下的耐旱性表现。【结果】水分胁迫下甘蔗叶片的PMP、MDA含量、Pro含量、SOD和POD酶活性升高,CHL含量和Pr含量降低,变化幅度因甘蔗基因型及水分胁迫程度差异而不同;隶属函数分析结果表明,不同程度水分胁迫下,割手密后代的耐旱能力不同,F_1代耐旱性较强,综合抗旱能力超过双亲的个体比例为82%,远高于F_2代;聚类分析表明,所有材料在轻度水分胁迫下可分为4大类群,其中,Ⅰ和Ⅱ类耐旱性最好,Ⅳ类次之,Ⅲ类耐旱性最差且全为F_2代材料,F_1代均分布于耐旱性较好的Ⅰ、Ⅱ、Ⅳ类群。重度胁迫下可分为3大类群,Ⅰ、Ⅲ类耐旱性较强,Ⅱ类耐旱性最差,F_1代(除云割F_108-473外)均分布在耐旱性较强的Ⅰ、Ⅲ类群;灰色关联度分析表明,不同程度水分胁迫下,各指标与耐旱性间的关联度不同。轻度胁迫下,关联度依次为PODSODPMPMDAPrCHLPro;重度胁迫下关联度依次为SODPrCHLPODPMPMDAPro。【结论】36份割手密F_1和F_2杂种材料中,云割F_108-536、云割F_211-179、云割F_211-8、云割F_108-474、云割F_108-398、云割F_108-254、云割F_211-261、云割F_211-151、云割F_108-538、云割F_108-391、云割F_211-188、云割F_211-37、云割F_107-150、云割F_211-258和云割F_211-90耐旱性较强,为强耐旱种质,可在甘蔗抗旱亲本培育及抗旱育种中加以重点利用;割手密耐旱特性在不同世代中的遗传表现不同,F_1代耐旱性强于F_2代;割手密后代耐旱性强弱与其父本割手密的气候生态类型、地理位置及海拔无明显相关性;PMP、MDA含量、CHL含量、SOD和POD酶活性5个生理生化指标与甘蔗耐旱性关联度较高,是耐旱性评价的优良指标。

Drought Resistance Evolution of F1 andF2 Hybrids from Five Climatic Ecotypes Saccharum spontaneum L.

【Objective】Drought is an important abiotic factor which has a severe impact on yield and qualities of sugarcane production. Saccharum spontaneum L., a wild resource of sugarcane, possesses a series of characters such as strong stress resistance, excellent perennial root and wide adaptability. Therefore, study on the drought resistance of its progenies, screening of drought resistant germplasms could provide a basis for drought resistance parent selection and realize breakthrough in breeding new sugarcane cultivars. 【Method】In this study, thirty-six F₁ andF₂ individuals from five ecotypes S. spontaneumwithYunrui innovation parents, introduced species and domestic species were bucket-planted in the greenhouse used as materials. The materials were treated by artificial water stress including normal water supply (as control), mild water stress and severe water stress at the early elongation stage of sugarcane. Subsequently, seven physiological and biochemical indexes including plasma membrane permeability (PMP), contents of malondialdehyde (MDA), chlorophyll (CHL), soluble protein (Pr) and proline (Pro) content and activities of superoxide dismutase (SOD) and peroxidase (POD) in sugarcane leaves were measured. Eventually, the drought resistance of F₁ andF₂ generations was evaluated comprehensively using fuzzy membership function method, cluster and grey relational analysis.【Result】Under water stress, the PMP, contents of MDA and proline, and the activities of SOD and POD raised, while the contents of CHL and PRO declined with different extents depending on sugarcane genotypes and stress degree. The results of fuzzy membership function analysis indicated that the drought resistance of S. spontaneum progeny varied was different under different water stress degrees, and the drought resistance of F₁ generation was stronger than that of F₂. The comprehensive drought resistance of individuals exceeded the parental up to 82% in F_1, which was much higher than F₂. The tested materials were classified into four groups under mild water stress by cluster analysis, and the drought resistance of groups Ⅰ and Ⅱ was the best, followed by group Ⅳ, and the worst was group Ⅲ. Moreover, the individuals of group Ⅲ were all from F₂, and all the F₁ individuals distributed in groupsⅠ, Ⅱ and Ⅳ, respectively, which had strong drought resistance. Simultaneously, they could be divided into three groups under severe stress, and the F₁ individualsexcepted YGF₁08-473 were all distributed in groups Ⅰ and Ⅲ, which showed stronger drought resistance than group Ⅱ. The grey relation analysis revealed that the correlation between physiological indexes and membership value was different because of water stress degree. Under mild stress, the correlation degree was in the order of POD＞SOD＞PMP＞MDA＞Pr＞CHL＞Pro. But, the correlation degree under severe stress was in the order of SOD＞Pr＞CHL＞POD＞PMP＞MDA＞Pro. 【Conclusion】In all thirty-six tested materials, YGF₁08-536, YGF₂11-261, YG F₁08-391, YGF₁08-254, YGF₂11-90, YGF₂11-8, YGF₂11-258, YGF₁08-398, YGF₁08-543, YGF₂11-151 and YGF₂11-53 were exhibited strong resistance under water stress. These materials could be utilized emphatically in parent selection and drought resistance breeding. Furthermore, genetic performance of drought resistance had significant difference between F₁ and F₂ hybrids of S.spontaneum, and the drought resistance of F₁ wasstronger than that of F_2. In addition, the drought resistance of S.spontaneum hybrids was no obvious correlation with paternal climate-type, geographic position and altitude. Based on the results of this study, PMP, contents of MDA and CHL, and activities of SOD and POD were good physiological and biochemical indicators with close correlation to drought resistance of sugarcane.