【作者】 游明鸿；

【导师】 张新全； 白史且；

【作者基本信息】 四川农业大学 ， 草业科学， 2011， 博士

【摘要】 老芒麦是青藏高原主推优良牧草之一,但相关牧草种子繁育技术较为落后。高原良种繁育对于解决青藏高原退牧还草及人工草地建设种源匮乏具有重要意义,本研究以川西北主推国审品种川草2号老芒麦(Elymus sibiricus L.cv.chuancao NO.2)原种为试验材料,结合川西北高原老芒麦种子产业化生产的实际技术需求,通过设计不同梯度的播种量、行距、肥力水平、栽培年限、除杂、收获时间等组合技术处理,研究对老芒麦生长发育、光合作用、生殖投入、生产能力、种子活力及杂草管理等的影响。经过4～5年研究,系统提出了川西北高原老芒麦种子丰产关键技术,主要结果如下：1.行距对分蘖数/m2、生殖枝数/m2、生殖枝比例、生殖枝高度、生殖枝直径等的极显著影响,造成穗柄长、穗柄直径、穗轴长、小穗数/生殖枝、小花数/生殖枝等的极显著差异,最终导致结实率、表现种子产量与实际种子产量的差异。行距60cm时,潜在种子产量、表现种子产量和实际种子产量最高,适宜在生产中推广。2.行距与施肥量是影响老芒麦产量的关键因素,主要通过增加枝条密度与高度影响草产量,通过增加生殖枝比例与小穗数/枝影响种子产量；行距40 cm、追复合肥225kg/hm2草产量最高,行距60 cm、追复合肥225kg/hm2种子产量最高。3.肥药混施对老芒麦分蘖、生长速度和生产性能等有显著影响。“尿素7500g/hm2+磷酸二氢钾300g/hm2+盖阔27g/hm2”、“尿素7500g/hm2+速效75g/hm2”和“尿素15000g/hm2+磷酸二氢钾300g/hm2+速效75g/hm2”3个组合拔节期混施有利于老芒麦种子生产。肥料与除草剂混施可减少田间作业次数、降低管理成本、达到增肥和除草的双重效果,值得在生产中推广与应用。4.基肥与追肥管理对不同年限的老芒麦花序性状和种子产量有极显著影响(P<0.01),影响由大到小顺序为：实际种子产量>潜在种子产量>表现种子产量>生殖枝密度>小花数/枝>种子数/枝>结实率。栽培年限对小花数/枝、种子数/枝、结实率、潜在种子产量、表现种子产量有显著影响,实际种子产量主要受年限与肥力互作的影响。5.分蘖期、拔节期追N显著提高了第2、3年干草产量(P<0.05),孕穗期追N与2～4年草产量都为负相关,分蘖期、拔节期、孕穗期追P、K肥都与干草产量表现为一定的负相关；基肥组成影响1～4年实际种子产量,分蘖期、拔节期追N可提高实际种子产量；分蘖期、拔节期和孕穗期追P、K肥对种子生产没有明显的促进作用。6.光合速率与营养枝、总分蘖和草产量显著负相关,与每生殖枝小花数和种子数及表现种子产量和实际种子产量呈显著正相关。通过适时灌水改善相对湿度和植株体内水分状况,可改变蒸腾速率来促进光合速率的增加,有利于光合干物质的积累,提高种子产量。7.老芒麦种子落粒起始时间为盛花期后20d～22d；落粒有种柄脱落与小穗柄脱落两种途径,但种柄脱落占主导地位；灌浆期、乳熟期、蜡熟期、完熟期落粒率分别为4.73%、20.78%、75.67%、87.73%；种子应在蜡熟期(盛花后36d～40d)进行收获。落粒起始时间与植株高度和小花柄直径呈显著负相关；乳熟前期(盛花后26d)落粒受种群密度与枝条直径影响大,但种子芒长是此阶段落粒的主要因素(R=0.9971)；蜡熟期(盛花后32d～36d)植株越高、枝条越细、小穗数/枝越少、小花数/枝越多则落粒越多,而花序柄长度与直径越大的落粒性显著降低;到成熟期落粒性与种群密度与枝条直径呈显著负相关。种子发育中、后期倒伏植株的落粒率低且千粒重大。8.老芒麦种子有较强的休眠性,休眠期约200d；收获后30d发芽势仅为0～0.75%,发芽率仅为0～1.25%；200d时发芽指数为36.05～85.48,活力指数为4.28～26.59。9.行距与老芒麦种子酸性磷酸酯酶活性呈极显著正相关(R=0.6673),与千粒重、发芽指数、活力指数及可溶性糖含量有一定的正相关,而与相对电导率和脱氢酶呈一定的负相关；施肥量与发芽指数、活力指数及可溶性糖含量呈显著正相关,与相对电导率、脱氢酶和磷酸酯酶活性呈负相关；播种量与可溶性糖含量呈显著负相关(R=-0.5061),与千粒重、发芽指数、活力指数及可溶性糖含量有一定的正相关。更多还原

【Abstract】 Elymus sibiricus L. is one of excellent quality forages, which has been widely used for artificial grassland establishment, rangeland improvement, and rangeland ecological protection in the Qinghai-Tibet Plateau. Strengthening seed production of E. sibiricus L. may solve the contradiction between demand and supply of seeds. But its relevant technology of seed production has been lagging hehind. In the present study, the State Approved Variety’E. sibiricus L.cv.chuancao NO.2’as being test material, which is mainly applied in the Sichuan Northwestern Plateau, together with the actual technical requirement for seed industrialization, we investigated the effects of the following factors on growth and development, photosynthesis, reproductive investment, production capacity, weed species and seed vigor. The factors studied include different gradient sowing rate, row spacing, fertility, cultivation year, the ways of weed cleaning and harvesting time. After 4-5 years of study, the main results are:1. Row spacing is highly significantly associated with seting percentage, presentation seed yield and harvested seed yield. The highest seed yield was obtained when the row space is 60cm. This may be worth spreading in practice. There are several possible explanations. Row spacing is significantly associated with tiller number and fertile tiller per square, fertile tiller ratio, fertile tiller height, fertile tiller diameter. Row spacing is also significantly associated with length and diameter of ear stalk, cob length, number of spikelet and floret per fertile tiller.2. Row spacing and fertilizing amount are the key factors to affect yield of E. sibisicus L, via effects on density and height of branch, ratio of fertile tiller, and spikelet per fertile branch.The highest grass yield was observed at the row space of 40cm and compound fertilizer of 225kg/hm2, and the highest seed yield was obtained at the row space of 60cm and compound fertilizer of 225kg/hm2.3.Mixing fertilizers and herbicides is significantly associated with tiller, growth rate and production performance of E. sibiricus L. Among different types of mixing of fertilizers and herbicides, seed yield of E. sibiricus L. was higher in the following groups than the control group, including 7500g/hm2 (NH2)2CO+300g/hm2 KH2PO4+27g/hm2 75% tribenuron dry SC,7500g/hm2 (NH2)2CO+75g/hm228% WP T-Y and 15000g/hm2 (NH2)2CO+300g/hm2 KH2PO4+75g/hm228% WP T-Y. Overall, mixing fertilizer and herbicides is worth applying widely, which may reduce the number of field operations, management cost, and achieve the dual effect of fertilizing and weeding.4. Different basal fertilizer and top dressing fertilizer had highly significant effect on traits of inflorescence and seed yield of E. sibiricus L. (P<0.01). The phenotype affected most is the harvested seed yield, and then, potential seed yield, presentation seed yield, fertile tiller density, florets/branch, seeds/branch, and that affected least is the seeding percentage. The harvested seedyield is mainly affected by the interaction of cultural year and fertilizer.5. Supplying nitrogen during the tillerring stage and jointing stage significantly increased hay grass yield of 2nd and 3rd year (P<0.05). However, Supplying nitrogen during the booting stage is negatively correlated to grass yield of the next three years. Supplying potassium and phosphate during any of the following three stages, tillerring, jointing and booting, is negatively correlated to hay grass yield. The component of basal fertilizer is associated with harvested seed yield of 1 to 4 year. Supplying nitrogen in the tillerring stage and jointing stage is associated with higher harvested seed yield. Applying phosphorus or potassium either in the tillerring, jointing or booting stage didn’t significantly promote seed yield.6. Photosynthetic rate had a significantly positive correlation to presentation seed yield and harvested seed yield because of the significantly positive correlation between photosynthetic rate and number of floret and seed per fertile tiller. But photosynthetic rate had a significantly negative correlation to grass yield because of the significantly negative correlation between photosynthetic rate and vegetative shoot, total tillers. Therefore, in order to increase seed yield, we may timely irrigate to improve the relative humidity and plant water status in vivo, which may promote photosynthetic rate and accumulate photosynthetic dry matter by changing transpiration rate.7. Seed of E. sibiricus L. began to shatter at 20d-22d after flowering stage. Seeds shattere via two ways-off seedstalk and off spikelet pedicel, with seedstalk shattering being the major one. The shattered rate is 4.73%、20.78%、75.67%、87.73%, respectively, at the time of milk stage, dough stage and to full ripening stage. Therefore, seed of E. sibiricus L. should be harvested in the dough stage (36d-40d after flowering). When seeds are almost mature, lodged, the plant showed low shattered rate and large 1000-seed weight. The starting and ending time of seed shattering is significantly negative correlated to the height of plant and diameter of pedicel. In the early milky stage (26d after flowering), the density of population and diameter of stalk affected seed shattering significantly. However, the length of awn was still the main factor to stimulate seed shattering (R=0.9971). In the ripening stage (32d-36d after flowering), the following factors are associated with larger number of shattered seed, high plant, fine branch, few spikelets/branch, and more florets/branch. In the full ripening stage, the seed shattering is significantly negative correlated to the density of population and diameter of stalk.8. Seed of E. sibiricus L. had strong dormancy, with about 200d dormancy period. After seed is stored 30d, the germination energy is only 0～0.75%, and germination rate is only 0～1.25%. When seed is stored 200d, the germination index is 36.05～85.48, and vigor index is 4.28～26.59.9. For seed of E. sibiricus L., row spacing was significantly positive correlated to the activity of acid phosphatase (R=0.6673). Row spacing had a certain positive correlation to 1000-grain weight, germination index, vigor index and soluble sugar contents. However, negative correlation is observed between row spacing and the relative conductivity and dehydrogenase. Amount of fertilization is positively correlated to germination index, vigor index and soluble sugar content. However, negative association is observed between amount of fertilization and the relative conductivity, dehydrogenase and phosphatase activity. Sowing rate significantly is negatively correlated to soluble sugar content (R=-0.5061), and a certain positive related to 1000-grain weight, germination index, vigor index and soluble sugar contents.更多还原