ABSTRACT
Objective: In order to correctly identify the different germplasm resources of Chuanmingshen violaceum and gain the excellent germplasm resources, SRAP molecular marker was used to analyze the genetic diversity of C. violaceum. Methods: C. violaceum was collected from seven different areas, which included 24 samples, the DNA fingerprint of C. violaceum was constructed with SRAP molecular marker, and the genetic diversity was analyzed. Results: Totally 374 bands were amplified by 37 primer pairs, of which 283 bands were polymorphic, and the polymorphic percentage was 75.67%. The SRAP-based genetic similarity coefficient of all samples ranged from 0.7267 to 0.9239, with a mean of 0.8150. The analysis of molecular variance showed higher percentages of genetic variation within population. All the accessions could be distinguished by SRAP markers. The cluster analysis results showed that 63 accessions were classified into seven groups, which were correlated with the geographical distribution of the accessions to some degree. The accessions from Langzhong and Jintang had higher diversity. Conclusion: There actually exists plentiful genetic diversity among the genetic resources of C. violaceum. SRAP marker is a useful method for analyzing the genetic diversity among C. violaceum accessions.
ABSTRACT
In Coffea arabica (arabica coffee), the phenotypic as well as genetic variability has been found low because of the narrow genetic basis and self fertile nature of the species. Because of high similarity in phenotypic appearance among the majority of arabica collections, selection of parental lines for inter-varietals hybridization and identification of resultant hybrids at an early stage of plant growth is difficult. DNA markers are known to be reliable in identifying closely related cultivars and hybrids. Sequence Related Amplified Polymorphism (SRAP) is a new molecular marker technology developed based on PCR. In this paper, sixty arabica-hybrid progenies belonging to six crosses were analyzed using 31 highly polymorphic SRAP markers. The analysis revealed seven types of SRAP marker profiles which are useful in discriminating the parents and hybrids. The number of bands amplified per primer pair ranges from 6.13 to 8.58 with average number of seven bands. Among six hybrid combinations, percentage of bands shared between hybrids and their parents ranged from 66.29% to 85.71% with polymorphic bands varied from 27.64% to 60.0%. Percentage of hybrid specific fragments obtained in various hybrid combinations ranged from 0.71% to 10.86% and ascribed to the consequence of meiotic recombination. Based on the similarity index calculation, it was observed that F1 hybrids share maximum number of bands with the female parent compared to male parent. The results obtained in the present study revealed the effectiveness of SRAP technique in cultivar identification and hybrid analysis in this coffee species. Rev. Biol. Trop. 59 (2): 607-617. Epub 2011 June 01.
En Coffea arabica (café arabica), el fenotipo y la variabilidad genética son bajos debido a la estrecha base genética y la autofecundación de la especie. Por su alta similitud fenotípica entre la mayoría de las colecciones de arábica, la selección de líneas parentales para hibridación entre variedades, y la identificación de los híbridos resultantes en una fase inicial de crecimiento, es difícil. Para la identificación de variedades estrechamente relacionadas y sus híbridos, los marcadores de ADN son confiables, pero los polimorfismos de amplificación de secuencias relacionadas (SRAP, por sus siglas en inglés) constituyen una nueva tecnología de marcadores moleculares basada en PCR. En este trabajo, sesenta progenies arábica híbridas, pertenecientes a seis cruces, fueron analizadas utilizando 31 marcadores altamente polimórficos. El análisis reveló siete tipos de perfiles de marcadores que son útiles en la discriminación de los progenitores y los híbridos. El número de bandas amplificadas por pares de cebadores estuvo entre 6.13 a 8.58 con un promedio de siete bandas. Entre las seis combinaciones de híbridos, el porcentaje de bandas compartidas entre híbridos y sus progenitores estuvo entre 66.29% y 85.71% con bandas polimórficas que variaron entre 27.64% y 60.0%. El porcentaje de fragmentos híbridos específicos obtenidos en diversas combinaciones híbridas varió entre 0.71% y 10.86% lo que se atribuye a la recombinación meiótica. Con base en el cálculo del índice de similitud, se observó que los híbridos F1 compartieron un número máximo de bandas con el progenitor femenino que con el masculino. Los resultados obtenidos en este estudio muestran la eficacia de la técnica de SRAP en la identificación de cultivos e híbridos de esta especie de café.