【作者】 李春红；

【导师】 曹敏建；

【作者基本信息】 沈阳农业大学 ， 作物栽培学与耕作学， 2011， 博士

【摘要】 大豆是我国主要的油料作物,也是需钾较多的作物。由于我国土壤速效钾缺乏,钾肥资源短缺,限制了大豆产量的提高。利用植物对环境胁迫的遗传多样性,发掘耐低钾种质资源,选育耐低钾大豆品种是解决这一问题的有效途径。本试验通过低钾土壤大田试验对72份东北三省新老大豆品种(系)进行筛选,并以筛选获得的不同低钾耐性的典型品种(系)为试材,通过大田、盆栽和水培试验,系统地对不同低钾耐性大豆的生长发育特性进行比较,并进行大豆耐低钾性状的遗传分析,其目的是为今后更好地应用大豆耐低钾种质资源、培育适合于缺钾土壤的大豆耐低钾新品种提供技术资料和理论依据。研究结果如下：1.耐低钾大豆基因型的筛选对72份大豆品种(系)的筛选结果表明,不同大豆品种(系)的耐性系数和叶片缺钾症状差异十分明显,多数大豆品种(系)对低钾胁迫的适应性为中等水平,对低钾胁迫比较敏感和耐性较强品种(系)较少。根据耐性系数和叶片缺钾症状可将供试品种(系)划分为3种类型,低钾敏感型、中间类型和耐低钾型。以筛选获得的典型材料耐低钾品种(系)铁豆36和T40,低钾敏感品系GD2910和GD8521进一步深入研究。2.不同低钾耐性大豆茎叶性状的差异低钾胁迫下不同的大豆品种(系)的株高总体上呈下降的趋势,但耐低钾品系T40的株高受低钾胁迫的影响最小。低钾胁迫下,不同耐性大豆品种(系)的主茎节数增加,开花以后增加的幅度较大,低钾敏感品系GD8521的主茎节数增加的最多。低钾胁迫使不同低钾耐性的大豆品种(系)的茎粗均减少,低钾敏感品系GD8521的茎粗减少幅度最大,低钾耐性品系T40的茎粗减少幅度较小。低钾胁迫对叶长影响最明显的时期是开花期,不同耐性大豆品种(系)的叶片长度均减少,耐低钾品种(系)的减少幅度比低钾敏感品系小。不同耐低钾性大豆品种(系)的叶柄长受低钾胁迫的影响并不一样,低钾敏感品系GD8521的叶柄长在低钾胁迫下明显受到抑制,耐低钾品系T40的叶柄长受低钾胁迫的影响较小。从分枝期开始,随着生长发育的推移,耐低钾大豆品种(系)症状叶比率逐渐降低或保持在低的水平；低钾敏感大豆品系症状叶比率逐渐上升或一直保持在高的水平。低钾胁迫下,低钾敏感品系的分枝数受到严重抑制,耐低钾品种(系)的分枝数受低钾胁迫的影响较小。低钾胁迫使不同低钾耐性大豆品种(系)的底荚节数升高,耐低钾品种(系)的升高幅度比低钾敏感品系小。3.不同低钾耐性大豆根系性状的差异盆栽试验表明,低钾胁迫下,不同耐性品种(系)的主根长、侧根长、侧根数和根瘤数均减少,低钾耐性品种(系)的变幅较小,敏感品种(系)的变幅较大。水培试验表明,在低钾胁迫下,不同低钾耐性的大豆品种(系)的根系总长、根系表面积、根系体积和根尖数均下降,耐低钾品种(系)的减少幅度明显小于低钾敏感品种(系)。低钾胁迫使敏感品种(系)的根系平均直径增加,耐性品种(系)的根系平均直径减少。4.不同低钾耐性大豆花荚性状的差异低钾胁迫下不同低钾耐性大豆始花期延迟,成熟期也延迟。低钾胁迫下,敏感品种(系)的单株荚数减少,耐性品种(系)的单株荚数增加；敏感品种(系)的单株粒数、百粒重的减少幅度大,耐性品种(系)的减少幅度小；不同低钾耐性大豆品种(系)的每荚粒数减少幅度大致相同。5.不同低钾耐性大豆干物质积累和分配的差异低钾胁迫下,不同低钾耐性大豆的各器官干物质积累均减少,总体上耐性品种(系)受低钾胁迫的影响较小,敏感品种(系)受低钾胁迫的影响较大。在分枝期,敏感品种(系)的茎秆干重受到低钾胁迫的影响较大,耐性品种(系)的根系受低钾胁迫的影响较小。开花以后,低钾耐性品种(系)的根系、叶片和茎秆干重的下降幅度均明显小于敏感品种(系)。成熟期,低钾下耐性品种(系)籽粒干重的下降幅度明显小于敏感品种(系)。耐性品种(系)开花前干物质分配合理,根、茎、叶生长比较协调,茎杆的干物质分配比例高于敏感品种(系),有利于光合产物运输和贮存。开花以后,耐性品种(系)根和叶的干物质分配比例减少幅度小,根和叶生长良好,有利于后期产量的形成。6.不同低钾耐性大豆钾素营养特性的差异低钾胁迫下,不同低钾耐性大豆叶片、茎秆、荚和籽粒的钾含量均降低,但是降低幅度不同,耐性品种(系)的各指标下降幅度小,并且低钾下的叶片、茎秆、荚和籽粒的钾含量相对较高,敏感品种(系)的各指标下降幅度大,钾含量相对较低。低钾胁迫下,不同低钾耐性大豆的钾积累量均下降,耐性品种(系)的钾积累量的下降幅度小,钾积累量比敏感品种(系)高。低钾胁迫下,不同低钾耐性大豆的钾利用效率明显升高,耐性品种(系)的钾利用效率的变化幅度小于敏感品种(系)。7.耐低钾大豆叶片缺钾症状和总根长的遗传分析以低钾耐性大豆Υ40为母本与两个敏感型大豆GD8521、GD2910为父本配制2个杂交组合,对2个组合的P1、P2、F1、F2和F2:35个世代,应用植物数量性状主基因+多基因混合遗传模型多世代联合分析方法,以缺钾症状叶片数为指标,进行大豆低钾耐性的遗传分析,结果表明,2个组合的遗传模型相同,主要由1对加性主基因+加性-显性多基因控制,两个组合F2控制叶片缺钾症状的主基因遗传率分别为56.72%和59.31%,多基因遗传率分别为20.28%和9.19%；F2:3控制叶片缺钾症状的主基因遗传率分别为50.32%和40.68%,多基因遗传力分别为17.72%和23.32%；主基因遗传力均高于多基因遗传率,主基因效应显著。低钾耐性大豆T40和低钾敏感大豆GD8521及其F1、F2和F2:35个世代总根长的遗传分析,结果表明,总根长受加性-显性-上位性多基因控制,在F2和F2:3世代,多基因遗传率分别为38.266%和41.884%,环境变异占表型变异分别为61.734%和58.116%。环境对植物总根长有较大的影响。更多还原

【Abstract】 Soybean is the main oil crops in China. The plant needs more potassium than other crops. However, both available potassium and potash fertilizer resource are deficient in China, which limits the improvement of soybean yield. Base on the plant genetic diversity to environmental stress, discovering the germplasm resources and breeding soybean varieties with tolerance to low potassium stress is an effective ways to solve the above problem. In this experiment, total of 72 soybean varieties (lines) from three northeast provinces in China were screened through the field experiment in low potassium soil, and typical varieties (lines) with different tolerance to low potassium stress were obtained. Furtherly, growth and development characters of these typical soybean varieties (lines) were compared through the field, potted and hydroponic experiment. Meanwhile, genetic characters of soybean tolerance to low potassium stress were studied. The purpose of this study is to provide technical and theoretical guidelines for better using soybean germplasm resources and breeding soybean varieties with tolerance to low potassium stress in the future. The results were as follows:1. Screening of soybean genotypes with tolerance to low potassium stressDifference of tolerance coefficient and K deficiency symptoms in leaf was obvious among the 72 soybean varieties (lines). In most of soybean varieties (lines), adaptability to low potassium stress was moderate. A few of soybean varieties (lines) showed more sensitive or tolerant phenotype to low potassium stress. According to tolerance coefficient and leaf K deficiency symptoms, these soybean varieties (lines) were divided into three types:sensitive type to low potassium, middle type to potassium and tolerant type to low potassium. Tiedou 36 and T40 as typical tolerant type varieties (lines), and GD2910 and GD8521 as typical sensitive type varieties (lines) were selected for further study.2. Differences in stem and leaf characters of soybeans with different tolerance to low potassium stressGenerally, plant height of soybeans was lower at each stage of growth period under low potassium stress. While, plant height of tolerance line T40 by low potassium stress was less affected.Number of stem nodes on all tested soybean varieties (lines) increased under low potassium stress, especially after blooming period.Number of stem nodes on GD8521, a sensitive type varieties (lines) to low potassium increased most. Moreover, low potassium stress reduced stem diameter of all tested soybean varieties (lines). Decreasing range of stem diameter on sensitive line GD8521 was the largest, but smaller on tolerant line T40.Leaf length of all tested soybean varieties (lines) was also decreased under low potassium stress, especially at blooming period. Decreasing range in tolerant varieties (lines) to low potassium was smaller than that in sensitive varieties (lines). Similarly, petiole length of sensitive line GD8521 was markedly inhibited, while, little effect was presented on tolerant line T40. From the beginning of branching period, ratio of K deficiency symptoms leave in tolerant varieties (lines) gradually reduced or maintained at a low level. On the contrary, the ratio in sensitive varieties (lines) gradually increased or maintained at a high level.Under low potassium stress, the number of branch of the sensitive varieties (lines) was seriously decreased, while tolerant line T40 was lightly affected. Low potassium stress increased node number of lowest pod, especially in sensitive varieties (lines).3. Differences in root characters of soybeans with different tolerance to low potassium stressThrough pot experiment, it was showed that taproot length, lateral root length, number of lateral root and root nodules of all tested varieties (strains) were reduced under low potassium stress. The negative effects on sensitive varieties (lines) were stronger than tolerant varieties (lines). Data from water culture experiments showed that low potassium stress reduced total root length, surface area of root, root volume and number of root tips of soybeans. Samely, the negative effects on sensitive varieties (lines) were stronger than tolerant varieties (lines). It was also found that low potassium stress increased root average diameter of sensitive varieties (lines) and decreased it in tolerance varieties (lines).4. Differences in flower and pod characters of soybeans with different tolerance to low potassium stressThe time of the first flower and mature of soybeans under low potassium stress were delayed. Low potassium stress reduced the number of pods per plant in sensitive varieties (lines), and increased the number of pods per plant in tolerance varieties (lines). Decreasing ranges in seed number per plant and 100-seed weight in sensitive varieties (lines) were larger than tolerant varieties (lines). There was no significant difference in the number of seeds per pod between sensitive and tolerant varieties (lines). 5. Differences in accumulation and distribution of dry matter in soybeans with different tolerance to low potassium stressAccumulations of dry matter in different organs of tested soybean varieties (lines) were reduced under low potassium stress. The negative effects on sensitive varieties (lines) were stronger than tolerant varieties (lines), such as accumulation of dry matter in stem at the stage of branching period, in roots, leave and stems after blooming period, and in seeds at the maturity stage.Before blooming period, distribution of dry matter in tolerant varieties (lines) was more reasonable than sensitive varieties (lines). The growth among root, stem and leaf was harmonious, and distribution ratio of dry matter in stem was higher in tolerant varieties (lines), which facilitate transport and storage of photosynthate product. After blooming period, decrease in distribution ratio of dry matter in root and leaf was lesser in tolerant varieties (lines), which facilitate yield formation.6. Differences in nutrition characters of potassium in soybeans with different tolerance to low potassium stressUnder low potassium stress, content of potassium in leaf, stem, pod and seed in all tested soybean varieties (lines) decreased, but there was a difference between tolerant and sensitive varieties (lines). Decreasing extent of above indexes was smaller, and K content was higher in tolerant varieties (lines) than in sensitive varieties (lines).K accumulation in all tested soybean varieties (lines) decreased under low potassium stress. Compared with sensitive varieties (lines), the tolerant varieties (lines) were less affected. Moreover, K utilization efficiency of all tested soybean varieties (lines) was significantly improved under low potassium stress, especiall for sensitive varieties (lines).7. Genetic analysis of leaf k deficiency symptom and total root length in soybeans with tolerance to low potassium stressT40 (tolerance to low-potassium stress) as the female parent, two sensitive lines GD8521and GD2910 as the male parent made two cross. Genetic analysis of the number of leaf with low potassium symptom was conducted applying the joint segregation analysis of a mixed genetic model of major gene plus polygene in five generations (P1, P2, F1, F2 and F2:3) derived from two crosses. The results showed that tolerance to low-potassium stress in soybean was dominated by one major gene with additive effects plus poly-genes with additive-dominance effects. Heritability of major geneswas 56.72% and 59.31% in F2 population from two cross, and that of poly-genes in F2 population was 20.28% and 9.19% respectively. Heritability of major genes was50.32% and 40.68% in F2:3 populations from two cross, and that of poly-genes in F2:3 populations was 17.72% and 23.32% respectively. Heritability of major gene in two crosses was more powerful than poly-genes. It indicated that the number of leaf with low potassium symptomthe in soybean was dominated by major genes.T40 (tolerance to low-potassium stress) as the female parent, sensitive lineGD8521 as the male parent made cross.Inheritance of total root length was analyzed applying the joint segregation analysis of a mixed genetic model of major gene plus polygene in five generations (P1, P2, F1, F2 and F2:3). The results showed that total root length was dominated by additive-dominance-epistatic gene. The heritability of poly-genes in F2 and F2:3 was 38.266%和41.884% respectively. In addition, the environmental variance in F2 and F2:3 accounted for 61.734%, and 58.116% of the phenotypic variance respectively, indicating that the environmental factors have some effect on total root length in tolerance to low-potassium soybean.更多还原