Mode of pollen spread in clonal seed orchard of Pinus koraiensis

The patterns of effective pollen dispersal and the relationships between pollen dispersal and genetic composition in Pinus koraiensis are still unclear. Hence, we investigated the mode of pollen dispersal of P. koraiensis in a clonal seed orchard in Lushuihe Forestry Bureau, Jilin Province, using SSR molecular markers tech-nique and the method of maximum likelihood. A total of 13 pairs of nuclear microsatellites po-lymorphic primers were used in the paternity analysis. We analyzed 100 progenies and 150 paternities. A total of 56 alleles were detected in 13 loci with 3-6 alleles (4.3 alleles in average) in a single locus. The primers of SsrPt_ctg7170 and SsrPt_ctg5333 had the maximum (6) and the minimum (3) alleles, respectively. The averaged values of observed heterozygosity, expected heterozygosity and polymorphism information content of experimental groups were 0.648, 0.601 and 0.533, respectively. The mating dis-tance of P. koraiensis followed an approximately normal distribution. The most effective pollen for the female parent came from male parent trees 15-45 m away with an average mating dis-tance of 32.60 m and the longest of 67.88 m. The pollen source of offspring was not random but greatly affected by the wind direction during the pollination season of P. koraiensis. These re-sults have important implications for seed or-chard design to improve the genetic quality of seeds and seed production.

The latest research progress of the Corona Virus Disease 2019 mutant strain"Omicron"

Coronavirus disease 2019(COVID-19)that broke out at the end of December 2019 has been raging for 3 years,bringing unpredictable harm to the physical and mental health of all mankind and global economic development.The new type of coronavirus pneumonia is a new type of respiratory infectious disease with a high incidence and fatality rate caused by SARS-CoV-2.Up to now,hundreds of millions of people have been infected with new coronary pneumonia worldwide,and millions of people have died.Due to the specificity of the new coronavirus itself and its high mutation rate,a series of different new coronavirus variants have appeared,which has caused the new crown pneumonia epidemic to repeat.Recently,the World Health Organization(WHO)announced a new variant"omicron"(omicron,B.1.1.529),and declared that the mutant strain may be highly infectious,antibody tolerant and highly resistant to vaccines.This article briefly reviews the latest research progress of the"omicron"variants.

Research progress on detection methods of the asymptomatic COVID- 19 infected persons

The global pandemic of COVID-19 has brought great harm and challenges to many countries and regions around the world.The majority of COVID-19 patients have typical clinical manifestations,but the number of asymptomatic infections is increasing as COVID-19 research continues and SARS-CoV-2 testing improves.Many asymptomatic COVID-19 patients with no obvious clinical symptoms are able to transmit the virus to others due to the presence of SARS-CoV-2 in their bodies,thus greatly accelerating the worldwide pandemic and posing great difficulty and threat to global epidemic prevention and control.Therefore,early detection and identification of asymptomatic infected persons through various testing methods are effective measures to control the COVID-19 pandemic.This article will provide a brief review of the available methods and techniques for detecting asymptomatic COVID-19 patients.