Despite Morocco's reliance on sunflower as an oilseed crop,little is known about its agronomic performance when sown in autumn or early winter.This knowledge gap is critical,as spring-sown varieties have shown dec...Despite Morocco's reliance on sunflower as an oilseed crop,little is known about its agronomic performance when sown in autumn or early winter.This knowledge gap is critical,as spring-sown varieties have shown declining performance in recent years under intensifying climate stress.Therefore,targeted breeding strategies could discover genotypes suitable for autumn or early winter sowing,with cold tolerance as a key selection criterion.Currently,‘Ichraq'is the only autumn-planted sunflower variety officially registered in Morocco,although efforts to release additional tolerant varieties are underway.This study evaluated 31 genotypes(MGB1to MGB31)selected from various environments under autumn planting conditions and conserved in the Moroccan Gene Bank.These genotypes were planted in early winter at a mountainous site known for its pronounced winter cold.Eighteen Morphological,physiological and agronomic parameters including initial vigor,leaf area,seed yield,oil content etc.,were assessed using both univariate and multivariate statistical approaches.Analysis of variance revealed significant genotypic differences across most traits,indicating substantial genetic variation.Notably,seed oil content ranged from 23.28%(MGB26)to 43.88%(MGB5),and seed yield from1400 kg/ha(MGB7)to 5400 kg/ha(MGB8).Principal component analysis(PCA)identified that the first principal component,accounting for over 24%of the total phenotypic variance,exhibits a strong positive loading of yield-related traits and chlorophyll content,while displaying a pronounced negative loading for oil content variables.This opposing gradient indicates a clear trade-off between vegetative productivity and oil accumulation across the evaluated genotypes.Hierarchical cluster analysis resolved the germplasm into two principal clusters with high within-group similarity,each further partitioned into relatively homogeneous subgroups.Notably,several genotypes outperformed the control variety Ichraq,underscoring their potential for autumn or early winter cultivation.Nonetheless,essential multi-environment trials remain to validate their phenotypic stability and to ascertain their value as genetic resources for sunflower breeding programs in Morocco and other Mediterranean agro-ecosystems.展开更多
The continuation of the isolated Amur tiger(Panthera tigris altaica)population living along the China-Russia border is facing serious challenges due to factors such as its small size(including 38 individuals)and canin...The continuation of the isolated Amur tiger(Panthera tigris altaica)population living along the China-Russia border is facing serious challenges due to factors such as its small size(including 38 individuals)and canine distemper virus(CDV).We use a population viability analysis metamodel,which consists of a traditional individual-based demographic model linked to an epidemiological model,to assess options for controlling the impact of negative factors through domestic dog management in protected areas,increasing connectivity to the neighboring large population(including more than 400 individuals),and habitat expansion.Without intervention,under inbreeding depression of 3.14,6.29,and 12.26 lethal equivalents,our metamodel predicted the extinction within 100 years is 64.4%,90.6%,and 99.8%,respectively.In addition,the simulation results showed that dog management or habitat expansion independently will not ensure tiger population viability for the next 100 years,and connectivity to the neighboring population would only keep the population size from rapidly declining.However,when the above three conservation scenarios are combined,even at the highest level of 12.26 lethal equivalents inbreeding depression,population size will not decline and the probability of extinction will be<5.8%.Our findings highlight that protecting the Amur tiger necessitates a multifaceted synergistic effort.Our key management recommendations for this population underline the importance of reducing CDV threats and expanding tiger occupancy to its former range in China,but re-establishing habitat connectivity to the neighboring population is an important long-term objective.展开更多
文摘Despite Morocco's reliance on sunflower as an oilseed crop,little is known about its agronomic performance when sown in autumn or early winter.This knowledge gap is critical,as spring-sown varieties have shown declining performance in recent years under intensifying climate stress.Therefore,targeted breeding strategies could discover genotypes suitable for autumn or early winter sowing,with cold tolerance as a key selection criterion.Currently,‘Ichraq'is the only autumn-planted sunflower variety officially registered in Morocco,although efforts to release additional tolerant varieties are underway.This study evaluated 31 genotypes(MGB1to MGB31)selected from various environments under autumn planting conditions and conserved in the Moroccan Gene Bank.These genotypes were planted in early winter at a mountainous site known for its pronounced winter cold.Eighteen Morphological,physiological and agronomic parameters including initial vigor,leaf area,seed yield,oil content etc.,were assessed using both univariate and multivariate statistical approaches.Analysis of variance revealed significant genotypic differences across most traits,indicating substantial genetic variation.Notably,seed oil content ranged from 23.28%(MGB26)to 43.88%(MGB5),and seed yield from1400 kg/ha(MGB7)to 5400 kg/ha(MGB8).Principal component analysis(PCA)identified that the first principal component,accounting for over 24%of the total phenotypic variance,exhibits a strong positive loading of yield-related traits and chlorophyll content,while displaying a pronounced negative loading for oil content variables.This opposing gradient indicates a clear trade-off between vegetative productivity and oil accumulation across the evaluated genotypes.Hierarchical cluster analysis resolved the germplasm into two principal clusters with high within-group similarity,each further partitioned into relatively homogeneous subgroups.Notably,several genotypes outperformed the control variety Ichraq,underscoring their potential for autumn or early winter cultivation.Nonetheless,essential multi-environment trials remain to validate their phenotypic stability and to ascertain their value as genetic resources for sunflower breeding programs in Morocco and other Mediterranean agro-ecosystems.
基金This work was supported by the National Natural Science Foundation of China(31971539)the National Science and Technology Basic Resources Survey Program of China(2019FY101700)a scholarship from the China Scholarship Council(202106040062).
文摘The continuation of the isolated Amur tiger(Panthera tigris altaica)population living along the China-Russia border is facing serious challenges due to factors such as its small size(including 38 individuals)and canine distemper virus(CDV).We use a population viability analysis metamodel,which consists of a traditional individual-based demographic model linked to an epidemiological model,to assess options for controlling the impact of negative factors through domestic dog management in protected areas,increasing connectivity to the neighboring large population(including more than 400 individuals),and habitat expansion.Without intervention,under inbreeding depression of 3.14,6.29,and 12.26 lethal equivalents,our metamodel predicted the extinction within 100 years is 64.4%,90.6%,and 99.8%,respectively.In addition,the simulation results showed that dog management or habitat expansion independently will not ensure tiger population viability for the next 100 years,and connectivity to the neighboring population would only keep the population size from rapidly declining.However,when the above three conservation scenarios are combined,even at the highest level of 12.26 lethal equivalents inbreeding depression,population size will not decline and the probability of extinction will be<5.8%.Our findings highlight that protecting the Amur tiger necessitates a multifaceted synergistic effort.Our key management recommendations for this population underline the importance of reducing CDV threats and expanding tiger occupancy to its former range in China,but re-establishing habitat connectivity to the neighboring population is an important long-term objective.
