RESUMEN
We screened and assessed published cotton simple sequence repeat (SSR) primers to establish a set of core SSR markers suitable for cotton major cultivars in China and analyzed genetic diversity based on the core marker set. Using a stepwise screening strategy, 12 leading cultivars for preliminary screening and 96 cultivars for rescreening were evaluated. A total of 184 polymorphic SSR markers were initially screened from 3299 candidates, and a core set of 52 SSR markers with wide genome coverage (2 markers per chromosome) was obtained. Among 96 major cultivars, 273 amplification genotypes were generated using the core marker set. Polymorphism information content values ranged from 0.28-0.83, with an average value of 0.56. The core SSR marker set detected on denaturing polyacrylamide gel electrophoresis indicated that the band genotype was either a single or double band on conventional cultivars, while most were double bands (65.4%). Among 56 hybrids, the average heterozygosis rate was 35.8%, ranging from 7.1-55.4%. Eighteen of 96 cultivars had distinct band genotypes. The genetic diversity analyzed using the of NTSYS-pc V2.10 software indicated that the Yangtze River valley cotton region had the highest polymorphic level, followed by Xinjiang and then the Yellow River valley. The genetic basis of conventional cultivars was narrower than that of hybrids. The core marker set can be used for fingerprint construction, variety identification, and purity tests of major cotton cultivars in China.
Asunto(s)
Quimera/genética , Gossypium/genética , Repeticiones de Microsatélite , Polimorfismo Genético , Alelos , Cruzamiento , Cromosomas de las Plantas/química , Genotipo , Técnicas de Genotipaje , Gossypium/clasificación , Heterocigoto , FilogeniaRESUMEN
Forty core primers were used to construct a DNA fingerprint database of 132 cotton species based on multiplex fluorescence detection technology. A high first successful ratio of 99.04% was demonstrated with tetraplex polymerase chain reaction. Forty primer pairs amplified a total of 262 genotypes among 132 species, with an average of 6.55 per primer and values of polymorphism information content varying from 0.340 to 0.882. Conflicting DNA homozygous ratios were found in various species. The highest DNA homozygous ratio was found in landrace standard cultivars, which had an 81.46% DNA homozygous ratio. The lowest occurred in a group of 2010 leading cultivars with a homozygous ratio of 63.04%. Genetic diversity of the 132 species was briefly analyzed using unweighted pair-group method with arithmetic means.