Progress in cotton improvement slowed in theUnited States the past 20 years,possiblyreflecting genetic stagnation.The pedigrees ofpopular cultivars contain many of the sameparents,evidence of a narrow genetic base.The...Progress in cotton improvement slowed in theUnited States the past 20 years,possiblyreflecting genetic stagnation.The pedigrees ofpopular cultivars contain many of the sameparents,evidence of a narrow genetic base.TheGossypium genetic base is wide,but only展开更多
The US cotton production system exemplifiesthe complex challenges that must be met in orderto reduce the genetic vulnerability of a majorcrop.Genetic vulnerability results from acombination of a crop’s evolutionary h...The US cotton production system exemplifiesthe complex challenges that must be met in orderto reduce the genetic vulnerability of a majorcrop.Genetic vulnerability results from acombination of a crop’s evolutionary history,trends in breeding and biotechnology practices,and grower Decisions based on inadequateinformation being available,all in response tothe inevitable pressures imposed by processor and consumer reqiurements.展开更多
By using a set of 315 recombinant inbred lines (RILs) from the cross Lemont (japonica)×Teqing (indica) and a complete linkage map with 186 well distributed RFLP markers and 3 morphological markers, a major gene (...By using a set of 315 recombinant inbred lines (RILs) from the cross Lemont (japonica)×Teqing (indica) and a complete linkage map with 186 well distributed RFLP markers and 3 morphological markers, a major gene (Xa4) and 10 QTLs and 9 pairs of epistasis loci conferring horizontal resistance to three strains of \%Xanthomonas oryza\% pv \%oryza (Xoo)\% were mapped. The Teqing allele at Xa4 on chromosome 11 acts as a dominant resistant gene against pathogen race CR4 and CX08, but as an additive QTL with a significantly (47%) reduced effect \{against the\} virulent strain, CR6. The major gene Xa4 exhibited stronger degree of race specificity. Most QTLs showed consistent levels of resistance against all three \%Xoo\% strains. The results suggest that a high level durable resistance to \%Xoo\% may be achieved by cumulative effects of multiple QTL.展开更多
文摘Progress in cotton improvement slowed in theUnited States the past 20 years,possiblyreflecting genetic stagnation.The pedigrees ofpopular cultivars contain many of the sameparents,evidence of a narrow genetic base.TheGossypium genetic base is wide,but only
文摘The US cotton production system exemplifiesthe complex challenges that must be met in orderto reduce the genetic vulnerability of a majorcrop.Genetic vulnerability results from acombination of a crop’s evolutionary history,trends in breeding and biotechnology practices,and grower Decisions based on inadequateinformation being available,all in response tothe inevitable pressures imposed by processor and consumer reqiurements.
文摘By using a set of 315 recombinant inbred lines (RILs) from the cross Lemont (japonica)×Teqing (indica) and a complete linkage map with 186 well distributed RFLP markers and 3 morphological markers, a major gene (Xa4) and 10 QTLs and 9 pairs of epistasis loci conferring horizontal resistance to three strains of \%Xanthomonas oryza\% pv \%oryza (Xoo)\% were mapped. The Teqing allele at Xa4 on chromosome 11 acts as a dominant resistant gene against pathogen race CR4 and CX08, but as an additive QTL with a significantly (47%) reduced effect \{against the\} virulent strain, CR6. The major gene Xa4 exhibited stronger degree of race specificity. Most QTLs showed consistent levels of resistance against all three \%Xoo\% strains. The results suggest that a high level durable resistance to \%Xoo\% may be achieved by cumulative effects of multiple QTL.
