【作者】 刘唐兴；

【导师】 官春云；

【作者基本信息】 湖南农业大学 ， 作物学， 2011， 博士

【摘要】 围绕甘蓝型油菜的抗倒性,于2006～2008年通过品种比较、密度、不同施氮时期和积水等4个试验,研究了不同抗倒性(抗倒性强、抗倒性中等、抗倒性弱)品种的农艺性状、理化性状及显微结构,并就有关栽培因子对倒伏和品质的影响进行了研究。主要结果如下：1.油菜倒伏主要发生在成熟后期,即收获前15天左右。农艺性状与倒伏指数的关联系数从大到小依次为：株高>主花序长度>分枝高度>一次分枝数>角果数>角果密度>根颈粗>分枝长度。抗倒性强的品种株高适中、分枝起点较低、主花序短、一次分枝的数量和长度中等、单株角果数多、结角密度大、生育前期根颈增粗快。2.利用BP神经网络模型对与抗倒性密切相关的5个性状与倒伏指数进行预测,发现多数品种的拟合性好,且两个样本的预测值完全处于实际值的置信区间；同时通过9个指标与倒伏指数的逐步回归分析,得回归方程：Y=-2.033-0.052X1+0.013X2+0.092X4+6.423X7-4.950Xs-0.385X9(y表示倒伏指数,x1表示株高,x2表示生物产量,)(4表示分枝高度,x7表示(薹茎+主花序)/(缩茎+伸长茎),x8表示薹茎/伸长茎,x9表示(薹茎+伸长茎)/缩茎)；回归结果表明,油菜茎秆各茎段的比例系数对倒伏的影响远大于株高、生物产量等指标。3.参试材料中,中双9号抗倒性最强,XYY6号抗倒性最弱,两者在(薹茎+主花序)/伸长茎、(薹茎+主花序)/(缩茎+伸长茎)和薹茎/伸长茎等比值上存在显著差异,中双9号的三个比值分别为2.10、1.61、0.92,XYY6号的三个比值分别为2.87、2.27、1.57,且两个抗倒性强品种中双9号和富油3号的比值非常接近；终花期根冠比以抗倒性最强的中双9号最高,为22.04%,显著高于其它抗倒性一般的品种。4.油菜主茎钾含量与蛋白质含量呈显著负相关,与主茎电阻率呈极显著负相关；主茎含水量与蛋白质含量、单株产量呈显著正相关,与倒伏指数呈显著负相关。终花期茎秆生化成分与倒伏指数的关联系数表现：粗纤维>钙>总糖>钾>蛋白质；成熟期茎秆生化成分与倒伏指数的关联系数表现：碳>根颈皮层干鲜比>纤维素>碳氮比>木质素>氮。抗倒性强的品种成熟期主茎木质素、氮、纤维素、硅、钾含量分别为抗到性弱的品种的1.189倍、1.462倍、0.904倍、7.158倍、0.182倍；根颈皮层的含水量与倒伏指数存在显著正相关。5.抗倒性强品种的维管柱木质部较厚,细胞排列比较整齐,多呈线性排列,其排列方向与主茎的方向基本一致；而抗倒性弱的品种木质部较薄,细胞排列无规则,与主茎生长方向一致的细胞线性排列较少。两类品种的射线分布有明显的差异,抗倒性强的品种的射线在形成层处与韧皮部连接紧密,但抗倒性一般的品种的射线与韧皮部的连接性差。6.在密度试验中,油菜的株高随着密度的增加而增加；主茎木质素含量随着密度增加而有增加的趋势,但未达显著水平；菜籽的品质指标与密度的变化关系存在基因型之间的差异；根颈粗和根体积与单株产量存在极显著正相关,侧根数目和根粗与单株产量的相关性较强,但未达显著水平,其它各根系性状与单株产量的相关性较弱。最长侧根长、侧根数目、根粗、根颈粗、根体积与倒伏指数呈负相关,均未达显著水平。7.油菜生育后期田间积水导致产量降低,倒伏程度加重,含油量明显下降,蛋白质含量略有提高,但对油酸和硫苷含量无显著影响；等量氮肥条件下,氮肥后移对产量、亚油酸和蛋白质含量无显著影响,但使含油量和油酸含量明显下降,后期施氮达70%时,倒伏程度显著加重。更多还原

【Abstract】 Centering on the lodging resistance of rapeseed (Brassica Napus L.), four experiments on varienties comparison, density, nitrogen application stage and hydrops were conducted in 2006～2008 to study the agronomic traits, physiological and chemical charaters and microstructure of rapeseed varienties with different lodging resistance, strong, mediun and weak, and effects of some cultivation factors on lodging and quality of rapeseed. The main results as follows:1. Lodging of rapeseed mainly occurred at post-maturation stage, about 15 days before harvesting. The correlation coefficients between agronomic trats and lodging index showed the trend of plant height> main inflorescence length> branch height > number of primary branches> silique number> silique density> width of root colla > branch length. Varieties with strong lodging resistance showed many features, such as moderate plant height, lower branch height, short main inflorescence, medium number and length of primary branches, more siliques per plant, big silique density, quickly increasing of root colla width, and so on.2. BP neural network model was used to forecast the lodging index and five agronomic characters which clearly related to the lodging resistance, results showed that the fitting was good and the forecasting values of two samples entirely lied in confidence interval. A regression equation was gained by stepped regression, Y=-2.033-0.052X1+0.013X2+0.092X4+6.423X7-4.950X8-0.385X9, in which Y, X1, X2, X4, X7, X8 and X9 represented lodging index, plant height, biomass and branch height, (bolting stem+main inflorescence)/(shortening stem+ elongated stem), bolting stem/ elongated stem, (bolting stem+elongated stem)/shortening stem respectively. The results showed that the effect of proportion of different stems of rapeseed on lodging was bigger than that of plant height and biomass on lodging.3. In tested materials, lodging resistance of Zhongshuang No.9 was strongest, while that of XYY 6 was weakest, and there existed significant difference in three ratios, (bolting stem+main inflorescence)/elongated stem, (bolting stem+main inflorescence)/ (shortening stem+ elongated stem) and bolting stem/elongated stem, between the two varieties. As for Zhongshuang No.9, the three ratios were 2.10,1.61 and 0.92 respectively, and their were 2.87,2.27 and 1.57 for XYY6. The three ratios between two strong lodging resistance varieties, Zhongshuang No.9 and Fuyou No.3, were very close. At late flowering stage, root/shoot ratio of Zhongshuang No.9 was highest, 22.4%, it was significantly higher than that of weak lodging resistance varieties.4. Significant negative correlation existed between K content and protein content, and resistivity of main stem. Significant positive correlation existed between water content of main stem and protein content, yield per plant, while significant negative correlation existed between water content of main stem and lodging resistance. At late flowering stage, correlation coefficients between biochemical composition and lodging index showed the trend of crude fiber> Ca> total sugar> K> protein, and which showed the trend of C> ratio of dry weight to fresh weight in cortex of root colla> fiber> C/N> lignin> N. At maturity, contents of lignin, N, fiber, Si and K in main stem of strong lodging resistance varieties were 1.189.1.462,0.904.7.158 and 0.182 times to those in main stem of weak lodging resistance varieties, respectively. Significant positive correlation existed between water content in cortex of root colla and lodging index.5. There existed clear difference in lignin characters between rapeseed varieties witg different lodging resistance. As for strong lodging resistance varieties, lignin was thick, arrangement of cell was regular and linear, and the arrangement direction was basically identical to main stem. As for weak lodging resistance varieties, lignin was thin, arrangement of cell was irregular. There existed clear difference in ray distribution between two types of varieties, ray of strong lodging resistance varieties connected tightly with phloem, which has not fault at cambium, while ray of weak lodging resistance varieties connected loosely with phloem.6. Expeiment of density showed that plant height of rapeseed was increased by density. Content of lignin in main stem was increased by density, while it was not significant. Genotype difference existed in correlation of quality of rapeseed and density. Significant positive correlation existed between yield per plant and root volume and width of root colla. Correlation between root number, root width and yield per plant was clear, while it was not significant, and the correlation between others root character and yield per plant was not clear. The correlation between lodging index and the length of the longest root, number of roots, width of root and root colla, root volume showed negative, while not significant.7. Hydrops in field at late growth stage of rapeseed resulted in clear decrease of yield and oil content, greater lodging and slightly increase of protein content, while content of oleic acid and glucosinolate changed unclearly. Under the same level of nitrogen fertilizer, backward removal of nitrogen fertilizer had not significant effect on yield and content of linoleic acid and protein, while it resulted in significant decrease of content of oil and oleic acid. If the proportion of nitrogen fertilizer at late growth stage reached to 70%, the lodging of rapeseed increased significantly.更多还原