Screening of rice (Oryza sativa) cultivars for resistance to rice black streaked dwarf virus using quantitative PCR and visual disease assessment

Rice black streaked dwarf virus (RBSDV) causing rice black streaked dwarf disease is transmitted by the small brown planthopper (SBPH, Laodelphax striatellus) in a persistent propagative manner. The disease is considered among the most destructive in rice production in east and southeast Asia. For sustainable control of the disease, planting resistant cultivars is the most economical and efficient method. The virus content in different rice cultivars was quantified using a TaqMan RT‐qPCR assay under greenhouse conditions and the disease was visually assessed in these cultivars in both greenhouse and field conditions. Results revealed significant positive moderate correlation (r = 0.3787; P = 0.0009) between the virus content and visual disease assessment in the greenhouse under forced inoculation. Among 66 rice cultivars, there was no significant difference in RBSDV genome equivalent copies (GEC) in seven cultivars, namely Lian‐dao 9805 (200.2 ± 12), Liangyou 3399 (206.6 ± 28), Ningjing 4 (206.6 ± 28), DaLiang 207 (302.0 ± 61), X 008 (354.0 ± 30), Shengdao 301 (658.4 ± 69) and Liangyou 1129 (679.5 ± 98). These cultivars were also visually assessed as resistant under greenhouse and field conditions. These cultivars could be used in disease management to reduce the likelihood of epidemics.     

助剂对氯虫苯甲酰胺药液理化性质及在玉米叶片上沉积分布的影响

为选择用于植保无人机作业的喷雾助剂,利用全自动张力仪和接触角测量仪测定添加4种不同喷雾助剂后0.5%氯虫苯甲酰胺药液的表面张力及在玉米叶片上的接触角,应用大疆T20型植保无人机进行田间喷雾,分析添加4种喷雾助剂对玉米冠层不同位置雾滴密度、雾滴覆盖率和雾滴沉积量的影响。结果显示,添加迈飞和Agrospred 910喷雾助剂后,药液的表面张力分别较未添加助剂时显著降低19.6%和30.1%;不同喷雾助剂对药液在玉米叶片上接触角的影响各不相同,添加Agrospred 910助剂后液滴接触叶片60 s后接触角降至11.92°;添加4种喷雾助剂能够有效提高玉米冠层的雾滴密度、雾滴覆盖率和雾滴沉积量,其中添加Agrospred 910助剂后雾滴密度、雾滴覆盖率及雾滴沉积量分别较对照增加了36.93%、35.92%和61.90%。表明在玉米田间使用植保无人机喷雾施药时,可以优选使用Agrospred 910喷雾助剂。