54个玉米自交系和16个杂交种苗期耐冷性鉴定与评价

Identification and evaluation of cold tolerance of 54 maize inbred lines and 16 hybrids at seedling stage

  • 摘要: 【目的】鉴定与评价贵州玉米自交系和杂交种的耐冷性,筛选出适宜高寒地区种植的耐冷种质资源,可为贵州高寒地区玉米的早春早播及育种提供参考。【方法】以54个贵州玉米核心自交系和16个贵州杂交种为供试材料,设室内低温处理(14℃)、室外低温处理(11.5℃)和对照处理(25℃),测定发芽天数、第2片叶天数、早期活力、地上部鲜重、地上部干重、叶绿素相对含量(SPAD)、初始荧光(Fo)、实际光能转换效率(ΦPSII)、最大光能转换效率(Fv/Fm)等9个耐冷相关指标,采用隶属函数综合分析、聚类分析等方法对自交系和杂交种苗期耐冷性进行鉴定,筛选出适宜高寒地区种植的耐冷种质资源。【结果】7个耐冷相关指标受到基因型和温度处理极显著或显著的影响。在室内低温处理下,第2片叶天数与早期活力、地上部鲜重呈显著负相关(P<0.05,下同),早期活力与地上部干重、地上部鲜重呈显著正相关,Fo与ΦPSII、Fv/Fm均呈显著负相关;在对照处理下早期活力与发芽天数呈显著负相关,而与地上部鲜重、地上部干重、SPAD呈显著正相关。对照处理的自交系和杂交种发芽天数、第2片叶天数均值均低于室内外低温处理的自交系和杂交种,SPAD、ΦPSII、Fv/Fm和地上部鲜(干)重的均值高于室内外低温处理,对照处理的自交系F_o的均值均低于室内外低温,杂交种低于室内低温,高于室外低温。对照处理下自交系和杂交种的地上部鲜重、地上部干重的变异系数较其他指标大,而ΦPSII和Fv/Fm的变异系数较小,说明对照处理下在自交系与杂交种呈现出类似的变异趋势。地上部干重和Fv/Fm在室内低温处理下的广义遗传力较高;室内外低温处理下自交系和杂交种耐冷相关指标的广义遗传力变化范围较大(0.01~0.95),表明大多数耐冷相关指标主要受遗传因素和冷害的影响。54个自交系被划分为三大类群,耐冷性排序为类群Ⅱ>类群Ⅲ>类群Ⅰ,类群Ⅱ隶属值最高的为GD932,为6.27,类群Ⅲ隶属值最高的材料是兆玉001和ES40,分别为6.10和5.95,可见类群Ⅱ和类群Ⅲ中的材料表现出较强的适应性。在16个杂交种中,金玉932和黔玉3号隶属值较高,分别为7.87和5.62,耐冷性较强,二者的耐冷杂优模式为瑞德×地方种质和瑞德×苏湾。【结论】隶属值排名前4的材料GD932、兆玉001、ES40、金玉932为耐冷性强种质,可用作高寒地区玉米育种的亲本材料。热带种质类群的耐冷性高于地方血缘与瑞德类群,瑞德血缘×地方血缘的杂优模式在玉米耐冷育种和高海拔早春早播中应重点利用。

     

    Abstract: 【Objective】The identification and evaluation of cold tolerance on maize inbred lines and hybrids in Guizhou as well as the screening of cold tolerant germplasm resources for alpine regions were conducted,which could provide references for early spring sowing and breeding of maize in Guizhou high-altitude and cold regions areas. 【Method】In this study,54 maize elite inbred lines and 16 hybrids in Guizhou were used, the 9 cold tolerance related indexes including days to emergence, days to the second leaf,early vigor,fresh weight above aground,dry matter weight above aground,relative chlorophyll content(SPAD), initial fluorescence(Fo), actual light energy conversion efficiency (ΦPSII), maximum light energy conversion efficiency(Fv/Fm) were measured indoor low temperature treatment(14 ℃), outdoor low temperatrue treatment(11.5 ℃) and control treatment(25 ℃) were set. Comprehensive membership function analysis and cluster analysis were applied to assess cold tolerance at the seedling stage of inbred lines and hybrids,aiming to screen and identify cold tolerant germplasm resources suitable for cultivation in high-altitude and cold regions regions. 【Result】Variance analysis revealed that 7 cold tolerance related indexes were significantly or highly significantly influenced by genotype and temperature treatment. Under cold stress indoor, days to the second leaf showed significantly negative correlation with early vigor and fresh weight above aground(P<0.05, the same below);early vigor was significantly and positively correlated with dry weight above ground and fresh weight above ground, Fo exhibited significant negative correlations with both ΦPSII and Fv/Fm. In control conditions, early vigor was significantly and negatively correlated with days to emergence, but significantly and positively correlated with fresh weight above ground, dry weight above ground and SPAD. The mean days to emergence and days to the second leaf of the inbred lines and hybrids treated in the control were both lower than those treated at indoor and outdoor low temperatures. The mean values of SPAD, ΦPSII, Fv/Fm and fresh(dry) weight above ground were higher than those treated at indoor and outdoor low temperatures. The mean value of Fo of the inbred lines treated in the control was lower than that at indoor and outdoor low temperatures, and that of the hybrids was lower than that at indoor low temperature, but higher than that at outdoor low temperature. Under the control treatment, the coefficients of variation of fresh weight above ground and dry weight above ground of the inbred lines and hybrids were larger than those of other indexes, while the coefficients of variation of ΦPSII and Fv/Fm were smaller. This indicated that under the control treatment, similar variation trends were presented in the inbred lines and hybrids. The broad-sense heritability of the dry weight above ground and Fv/Fm was relatively high under indoor low temperature treatment. The broad-sense heritability variation range of cold tolerance related indexes of inbred lines and hybrids under indoor and outdoor low temperature treatment was relatively large(0.01-0.95), indicating that most cold tolerance related indexes were mainly affected by genetic factors and cold damage. Fifty-four inbred lines were classified into three major groups. The order of cold resistance was group Ⅱ > group Ⅲ > groupⅠ. The material with the highest membership value of group Ⅱ was GD932, which was 6.27. The materials with the highest membership values of group Ⅲ were Zhaoyu 001 and ES40, which were 6.1 and 5.95 respectively. It could be seen that the materials in group Ⅱ and group Ⅲ exhibited strong adaptability. Among the 16 hybrids, the membership values of Jinyu 932 and Qianyu No. 3 were relatively high, which were 7.87 and 5.62 respectively, and they had strong cold tolerance. The cold tolerant hybrid superior models of the two were Red×local germplasm and Red×Suwan. 【Conclusion】The top 4 materials in terms of total membership values, GD932, Zhaoyu 001, ES40 and Jinyu 932, are strong cold tolerant germplasms and can be used as parent materials for corn breeding in high-altitude and cold regions. The cold tolerance of tropical germplasm groups is higher than that of local background and Red groups. The hybrid superior model of Red background×local background should be focused on in cold tolerant breeding of maize and early spring sowing at high altitudes.

     

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