东北旋耕制度下垄作与平作甜菜产质量差异

为研究东北旋耕制度条件下甜菜平作和垄作对于甜菜产量和质量的影响,2017年以‘H004’为试验材料,采用分区设计的实验方法,在哈尔滨呼兰区多年旋耕地测定了在平作和垄作栽培条件下甜菜的块根产量、绿茎叶产量、含糖率、甜菜地下和地上部位的干物质量比例以及不同耕作条件下不同土层的土壤含水量和容重。研究发现转旋耕条件下平作和垄作甜菜含糖量没有显著差异,但是垄作甜菜块根产量要明显优于平作甜菜,垄作甜菜块根单产达到87.8 t/hm2,而平作甜菜块根单产仅为72.9 t/hm2。此外研究发现平作甜菜地上部分干物质积累较多,如平作甜菜根/地上部干物质比值要显著低于垄作甜菜。同时发现垄作栽培土壤含水量及土壤疏松程度均优于平作,如在20-26 cm土层中垄作土壤的容重和含水量分别为1.38 g/cm3和21.96%,而在20~26 cm平作土壤的容重和含水量仅为1.56 g/cm3和19.35%。本研究表明在东北旋耕制度条件下,垄作栽培更适于甜菜生产,也为下一步研发东北高产高糖甜菜栽培模式鉴定重要基础。     

不同施N策略对棉花SPAD值和产量的影响

通过棉花膜下滴灌不同施氮策略对产量及氮素养分和叶绿素值相关性的影响研究,为膜下滴灌精准施氮技术提供理论依据。在田间分别设2个施N量水平,3个追氮比例,共6个处理,比较产量差异,并采用SPAD-502叶绿素仪测定分析SPAD值和土壤碱解氮变化特征。结果表明：360 kg/hm2的施氮量可获得3040.5 kg/hm2的高产,但3个追氮比例策略对产量影响差异小,240 kg/hm2的施氮量下3个追氮比例策略对产量影响差异显著;240 kg/hm2施氮量的SPAD值整体较低,3个追氮比例策略在蕾期以后的SPAD值差异不显著,而360 kg/hm2施氮量处理在蕾期以后的SPAD值差异显著;高产棉花需肥规律的推荐比例的SPAD值与土壤碱氮相关性R2值达到0.9367的最高水平。结论:充足供氮时,调整追氮比例对高产影响不大;供氮不足不易获得高产,但调整追氮比例有一定的增产空间;施氮肥充足并按照棉花需肥规律的推荐比例施氮,可延缓棉花早衰失绿,形成高产。     

3种PCR程序扩增甜菜SSR及InDel标记的比较

本研究旨在扩增出条带清晰、非特异性条带少的SSR/InDel标记产物。选择来自6个国家的12份不同基因型甜菜品种,利用SSR及InDel两种标记方法,Touch-down PCR、梯度PCR及常规固定退火温度PCR三种反应程序扩增产物。通过比较扩增产物的多态性、稳定性、清晰度选择适合两种分子标记方法的PCR反应程序。结果表明:Touch-down PCR法可以通过一次反应即顺利扩增出带型清晰,无无效带,扩增效果稳定的样本产物。梯度PCR法扩增结果不稳定,有非特异性条带出现并且弥散现象严重。固定退火温度PCR扩增结果因引物不同而差异较大,同时伴有弥散现象。Touch-down PCR扩增产物特异性,稳定性均高于梯度PCR及固定退火温度PCR,且较梯度PCR法省略了摸索最适退火温度的过程。因此,推荐使用Touch-down PCR程序进行甜菜SSR与InDel分子标记法研究。     

施钾量对膜下滴灌甜菜光合性能以及对产量和品质的影响

膜下滴灌技术被广泛应用于内蒙古冷凉干旱地区的甜菜生产中。为探明施钾量对膜下滴灌甜菜光合生理特性和产质量的影响及其适宜钾肥用量, 于2014?2015年在内蒙古凉城县设K₂O 0、90、180、270和360 kg hm ^-25个施肥处理进行了研究。结果表明, 钾素能够提高甜菜的光合性能, 如促进株高、叶面积指数、净光合速率的增加; 施钾肥180、270和360 kg hm ^-2显著提高了叶丛快速生长期甜菜的净光合速率, 影响净光合速率的最主要因素是RuBPCase活性, 其次是气孔导度, 净光合速率与甜菜产量呈极显著正相关。适宜的钾肥用量有利于块根、叶柄和叶片干重的增加及产量增加, 但施钾过量, 块根干物质分配比例下降, 含糖率下降, 块根干物质分配比例与甜菜含糖率呈显著正相关。施钾量270 kg hm ^-2时产量最高, 90 kg hm ^-2时含糖率最高, 当施钾量大于180 kg hm ^-2时, 块根中K ⁺、Na ⁺含量增加, 大于270 kg hm ^-2时, 块根中α-氨基酸含量增加, 施钾量180 kg hm ^-2时产糖量最高。综合考虑施钾量对膜下滴灌甜菜产量和品质的影响, 内蒙古甜菜种植优势区域的钾肥推荐施用量为180 kg hm ^-2。     

Impact of the Cropping Systems of a Minor Dry Season on the Growth, Yields and Nitrogen Uptake of Maize (Zea mays L) Grown in the Humid Tropics during the Major Rainy Season

A field study evaluated the residual effect of a cropping system in two minor (dry) seasons on the productivity pattern and nitrogen utilization of a maize crop grown in the subsequent major (wet) seasons. The cropping systems established in the minor seasons, where evaporation exceeds rainfall, were either monocultures of maize (Zea mays L), or maize intercropped with either common bean (Phaseolus vulgaris L) or sunhemp (Crotolaria juncea L). In addition, monocultures of two green manures, namely sunhemp (Crotolaria juncea) or Tithonia (Tithonia diversifolia), were established. The residues of maize and beans and the green manures were incorporated at the end of the minor season; at the onset of rains in the major season, maize crops were established on the same plots. Germination of maize was not affected by the previous cropping system. In contrast, crop growth and yields of maize and nitrogen utilization were affected by the previous cropping system. Optimum growth and highest yields were procured in maize that was grown after a green manure crop. Similarly, although the yields were high, the planting of a green manure crop reduced nitrogen utilization by maize in the major season, thereby indicating its potential contribution to sustainability, due to its lower mining of soil nitrogen. On the basis of the results of this two‐year study, the impact of cropping systems in minor seasons on the productivity of maize, a very important highland cereal in the tropics, grown under rain‐fed conditions in a major season, is presented.