This paper begins with the overthrow of the concept of combining ability in crossbreeding by the concept of heritability.The reason is that general combining ability changes with the number and kind of pure strains in...This paper begins with the overthrow of the concept of combining ability in crossbreeding by the concept of heritability.The reason is that general combining ability changes with the number and kind of pure strains in the foundation stock and hence special combining ability changes also,so that work with different kinds of pure strains in the foundation stock cannot be compared.Hence combining ability is useless as a parameter to predict the amount of heterosis expected in the next generation.On the other hand,since each cross has a separate heritability,it can be applied to a cross population just as successfully as in purebreeding.Since the same concept holds in both cases,resort to any other concept would be superfluous.That's why combining ability must be rejected.Another reason(not given in the full text)is,an infinite number of pure strains would be required in the foundation stock for its results to be comparable with those of the heritability theory,which disposes of its utility altogether.The main content of the thesis is then the centennial enigma of heterosis can be resolved by Descarte's theoretic method of deduction.Accordingly we start from the definition of heterosis.H=F¡-MP,where H is heterosis,F,is the first generation offspring,MP is the mean of the parents or midparent,and from the use of a binomial random variable and its extention to the multinomial case derive the basic relations of heterosis with its components.Starting with second degree statistics,we obtain Vn=Vr,-2cov(F,,MP)+Vup,where V and cov stand for variance and covariance.The equations of heterosis are v„=(1/2)Na²+(1/4)Nd’+Vr(F,)=additive dominance F,epistasis Vup=(1/2)Na’+(1/2)V1,additive parental epistasis V„=(1/4)Nd’+V(F)+(1/2)V1,dominance F,epistasis parental epistasis.where N is number of genes controlling a trait,a=(P1-P,)12,d is deviation from midparent,while the variance components are all indicated by their names under the repective terms.It turns out that all these can be easily computed from the data so that the problem becomes a simple one which any college student may solve.In other words,the right answers are found when the right questions are asked.Who had ever shown that the heritability principle is inapplicable in crossbreeding,e.g.,in a crossing of two pure strains?From this cue arose the realization that the F,of a cross of two pure strains must also be a Mendelian population,with p and q both equal to 1/2 which simplifies the algebra outright.This Heritability Theory of Heterosis,or HTH in capital letters,re-sts on 2 initial anguments:1)Since 0.5+0.5=1,crossing two pure strains gives a population which is only a special case of pure-breeding,thereforea heritability coefficient must exist for the F1;2)Our problem reduces to that of finding that coefficient;the an-swer is given by the additive component divided by Ve.,i.e.,(1/2)No'1 Vp..which is readily found from the solution of the het-erosis equations.Thus the elemnal enigma of heterosis is resolved!This happened at the end of the 20th century.We now come to the second point of the discovery,the new genetic parameter crossheritability which will rise in size with the increase of the number of times it's used and form the link between breeding and evolution.The advent of the Age of Evolution Engineering in the 21st century marks a totally new era,showing that artificial will ultimately supercede natural selection,with the long span of time element eliminated.For agriculture at least,it means there is no limit to the increase of food supply by the new method,with the concentra-tion of desirable genes by hybridization in place of the old theory of their fixation.Genetic gain is achieved through artificial selec-tion,with an 80%saving of time,labor and cost by adoption of the new method.Applied to a further increase in all kinds of agri-cultural products including hybrd rice,it means that a huge eacalation,in fact a New Green Revolution,on a much langer scale than that of any such before,is in view,provided it is adopted in our research and educational institutions as early as possible,ere its spread elsewhere.The possibilities from the evolution point of view can only be pictured by science fiction.展开更多
Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threaten...Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threatened by the unpre-dictable changes in climate,specifically high temperatures.Breeding heat-tolerant,high-yielding cotton cultivars with wide adaptability to be grown in the regions with rising temperatures is one of the primary objectives of modern cotton breeding programmes.Therefore,the main objective of the current study is to figure out the effective breed-ing approach to imparting heat tolerance as well as the judicious utilization of commercially significant and stress-tolerant attributes in cotton breeding.Initially,the two most notable heat-susceptible(FH-115 and NIAB Kiran)and tolerant(IUB-13 and GH-Mubarak)cotton cultivars were spotted to develop filial and backcross populations to accom-plish the preceding study objectives.The heat tolerant cultivars were screened on the basis of various morphological(seed cotton yield per plant,ginning turnout percentage),physiological(pollen viability,cell membrane thermostabil-ity)and biochemical(peroxidase activity,proline content,hydrogen peroxide content)parameters.Results The results clearly exhibited that heat stress consequently had a detrimental impact on every studied plant trait,as revealed by the ability of crossing and their backcross populations to tolerate high temperatures.However,when considering overall yield,biochemical,and physiological traits,the IUB-13×FH-115 cross went over particularly well at both normal and high temperature conditions.Moreover,overall seed cotton yield per plant exhibited a posi-tive correlation with both pollen viability and antioxidant levels(POD activity and proline content).Conclusions Selection from segregation population and criteria involving pollen viability and antioxidant levels concluded to be an effective strategy for the screening of heat-tolerant cotton germplasms.Therefore,understanding acquired from this study can assist breeders identifying traits that should be prioritized in order to develop climate resilient cotton cultivars.展开更多
Drought stress(DS)is one of the most critical environmental abiotic stresses for wheat production in the arid environments.Selection of high-yielding genotypes tolerant to DS can play a significant role in mitigation ...Drought stress(DS)is one of the most critical environmental abiotic stresses for wheat production in the arid environments.Selection of high-yielding genotypes tolerant to DS can play a significant role in mitigation the negative impacts associated with DS.In the present study,generation means analysis(GMA)was used to study the performance of two crosses under well irrigation(WI)and deficit irrigation[cross I(Line 44×Shandweel-1)and cross II(Line 20×Sakha 93)].Significant differences were observed for days to heading(DH),days to maturity(DM),plant height(PH),spike length(SL),number of spikes per plant(NS/P),number of grains per spike(NG/S),thousand-grain weight(TGW),grain yield per plant(GY/P),and proline content(PC)in the six populations of the two crosses within each irrigation level.Cross II had early maturity and the highest PC,NS/P,TGW,and GY/P regardless of the irrigation level.Cross I showed positive significant relative heterosis and heterobeltiosis for GY/P under the two irrigation levels.The inheritance of characters of cross I revealed additive,dominant,and epistatic effects,which varied with trait and stress.Additive genetic effects predominated in DH,SL,and PC,while non-additive were found in DM,NS/P,NG/S,and GY/P.Narrow-sense heritability estimates(h^(2) n)were high for DH and PC,moderate to high for PH and SL,moderate for DM,NG/S,NS/P,and TGW,and low for GY/P.Based on different drought indices the populations BC_(1),BC_(2),F_(1),and P1 of cross II and BC1 of cross I were more tolerant to drought stress.Therefore,PC,TGW and DH can be used as selection indicators to improve wheat for drought tolerance in early generations and other yield components traits in late generations.The second cross(Line 20×Sakha 93)shows promise and is of interest to a drought tolerance breeding program,where wheat breeders can use recombinant breeding strategies to construct desirable drought stress genes.Correlation and path coefficient revealed that TGW and PC were the main contributor in grain yield in both environments.展开更多
Dear Editor,In recent years,generative artificial intelligence(GAI)has gained unprecedented attention.Unlike conventional AI,GAI can generate innovative and meaningful content across texts,images,and videos.The succes...Dear Editor,In recent years,generative artificial intelligence(GAI)has gained unprecedented attention.Unlike conventional AI,GAI can generate innovative and meaningful content across texts,images,and videos.The success of OpenAI’s ChatGPT has driven global tech companies to develop high-performancemodels and integrate GAI into products.1 This AI arms race continues,as shown by OpenAI’s textto-video model,Sora,and Anthropic’s new large language model,Claude 3.The release of DeepSeek V3/R1 has sparked a global AI cost revolution.GAI is transforming key sectors like business,finance,law,and healthcare,heralding a new era in AI technology.展开更多
文摘This paper begins with the overthrow of the concept of combining ability in crossbreeding by the concept of heritability.The reason is that general combining ability changes with the number and kind of pure strains in the foundation stock and hence special combining ability changes also,so that work with different kinds of pure strains in the foundation stock cannot be compared.Hence combining ability is useless as a parameter to predict the amount of heterosis expected in the next generation.On the other hand,since each cross has a separate heritability,it can be applied to a cross population just as successfully as in purebreeding.Since the same concept holds in both cases,resort to any other concept would be superfluous.That's why combining ability must be rejected.Another reason(not given in the full text)is,an infinite number of pure strains would be required in the foundation stock for its results to be comparable with those of the heritability theory,which disposes of its utility altogether.The main content of the thesis is then the centennial enigma of heterosis can be resolved by Descarte's theoretic method of deduction.Accordingly we start from the definition of heterosis.H=F¡-MP,where H is heterosis,F,is the first generation offspring,MP is the mean of the parents or midparent,and from the use of a binomial random variable and its extention to the multinomial case derive the basic relations of heterosis with its components.Starting with second degree statistics,we obtain Vn=Vr,-2cov(F,,MP)+Vup,where V and cov stand for variance and covariance.The equations of heterosis are v„=(1/2)Na²+(1/4)Nd’+Vr(F,)=additive dominance F,epistasis Vup=(1/2)Na’+(1/2)V1,additive parental epistasis V„=(1/4)Nd’+V(F)+(1/2)V1,dominance F,epistasis parental epistasis.where N is number of genes controlling a trait,a=(P1-P,)12,d is deviation from midparent,while the variance components are all indicated by their names under the repective terms.It turns out that all these can be easily computed from the data so that the problem becomes a simple one which any college student may solve.In other words,the right answers are found when the right questions are asked.Who had ever shown that the heritability principle is inapplicable in crossbreeding,e.g.,in a crossing of two pure strains?From this cue arose the realization that the F,of a cross of two pure strains must also be a Mendelian population,with p and q both equal to 1/2 which simplifies the algebra outright.This Heritability Theory of Heterosis,or HTH in capital letters,re-sts on 2 initial anguments:1)Since 0.5+0.5=1,crossing two pure strains gives a population which is only a special case of pure-breeding,thereforea heritability coefficient must exist for the F1;2)Our problem reduces to that of finding that coefficient;the an-swer is given by the additive component divided by Ve.,i.e.,(1/2)No'1 Vp..which is readily found from the solution of the het-erosis equations.Thus the elemnal enigma of heterosis is resolved!This happened at the end of the 20th century.We now come to the second point of the discovery,the new genetic parameter crossheritability which will rise in size with the increase of the number of times it's used and form the link between breeding and evolution.The advent of the Age of Evolution Engineering in the 21st century marks a totally new era,showing that artificial will ultimately supercede natural selection,with the long span of time element eliminated.For agriculture at least,it means there is no limit to the increase of food supply by the new method,with the concentra-tion of desirable genes by hybridization in place of the old theory of their fixation.Genetic gain is achieved through artificial selec-tion,with an 80%saving of time,labor and cost by adoption of the new method.Applied to a further increase in all kinds of agri-cultural products including hybrd rice,it means that a huge eacalation,in fact a New Green Revolution,on a much langer scale than that of any such before,is in view,provided it is adopted in our research and educational institutions as early as possible,ere its spread elsewhere.The possibilities from the evolution point of view can only be pictured by science fiction.
基金Centre for Advance Studies in Agricultural Food Security and Punjab Agricultural Research Board for providing funds under CAS-PARB project(No.964).
文摘Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threatened by the unpre-dictable changes in climate,specifically high temperatures.Breeding heat-tolerant,high-yielding cotton cultivars with wide adaptability to be grown in the regions with rising temperatures is one of the primary objectives of modern cotton breeding programmes.Therefore,the main objective of the current study is to figure out the effective breed-ing approach to imparting heat tolerance as well as the judicious utilization of commercially significant and stress-tolerant attributes in cotton breeding.Initially,the two most notable heat-susceptible(FH-115 and NIAB Kiran)and tolerant(IUB-13 and GH-Mubarak)cotton cultivars were spotted to develop filial and backcross populations to accom-plish the preceding study objectives.The heat tolerant cultivars were screened on the basis of various morphological(seed cotton yield per plant,ginning turnout percentage),physiological(pollen viability,cell membrane thermostabil-ity)and biochemical(peroxidase activity,proline content,hydrogen peroxide content)parameters.Results The results clearly exhibited that heat stress consequently had a detrimental impact on every studied plant trait,as revealed by the ability of crossing and their backcross populations to tolerate high temperatures.However,when considering overall yield,biochemical,and physiological traits,the IUB-13×FH-115 cross went over particularly well at both normal and high temperature conditions.Moreover,overall seed cotton yield per plant exhibited a posi-tive correlation with both pollen viability and antioxidant levels(POD activity and proline content).Conclusions Selection from segregation population and criteria involving pollen viability and antioxidant levels concluded to be an effective strategy for the screening of heat-tolerant cotton germplasms.Therefore,understanding acquired from this study can assist breeders identifying traits that should be prioritized in order to develop climate resilient cotton cultivars.
文摘Drought stress(DS)is one of the most critical environmental abiotic stresses for wheat production in the arid environments.Selection of high-yielding genotypes tolerant to DS can play a significant role in mitigation the negative impacts associated with DS.In the present study,generation means analysis(GMA)was used to study the performance of two crosses under well irrigation(WI)and deficit irrigation[cross I(Line 44×Shandweel-1)and cross II(Line 20×Sakha 93)].Significant differences were observed for days to heading(DH),days to maturity(DM),plant height(PH),spike length(SL),number of spikes per plant(NS/P),number of grains per spike(NG/S),thousand-grain weight(TGW),grain yield per plant(GY/P),and proline content(PC)in the six populations of the two crosses within each irrigation level.Cross II had early maturity and the highest PC,NS/P,TGW,and GY/P regardless of the irrigation level.Cross I showed positive significant relative heterosis and heterobeltiosis for GY/P under the two irrigation levels.The inheritance of characters of cross I revealed additive,dominant,and epistatic effects,which varied with trait and stress.Additive genetic effects predominated in DH,SL,and PC,while non-additive were found in DM,NS/P,NG/S,and GY/P.Narrow-sense heritability estimates(h^(2) n)were high for DH and PC,moderate to high for PH and SL,moderate for DM,NG/S,NS/P,and TGW,and low for GY/P.Based on different drought indices the populations BC_(1),BC_(2),F_(1),and P1 of cross II and BC1 of cross I were more tolerant to drought stress.Therefore,PC,TGW and DH can be used as selection indicators to improve wheat for drought tolerance in early generations and other yield components traits in late generations.The second cross(Line 20×Sakha 93)shows promise and is of interest to a drought tolerance breeding program,where wheat breeders can use recombinant breeding strategies to construct desirable drought stress genes.Correlation and path coefficient revealed that TGW and PC were the main contributor in grain yield in both environments.
基金supported in part by the National Key Research and Development Program of China(No.2023YFE0119800)in part by the National Natural Science Foundation of China(No.72422015 and No.52277095).
文摘Dear Editor,In recent years,generative artificial intelligence(GAI)has gained unprecedented attention.Unlike conventional AI,GAI can generate innovative and meaningful content across texts,images,and videos.The success of OpenAI’s ChatGPT has driven global tech companies to develop high-performancemodels and integrate GAI into products.1 This AI arms race continues,as shown by OpenAI’s textto-video model,Sora,and Anthropic’s new large language model,Claude 3.The release of DeepSeek V3/R1 has sparked a global AI cost revolution.GAI is transforming key sectors like business,finance,law,and healthcare,heralding a new era in AI technology.
