Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/7/2002
Publication Date: 11/1/2002
Citation: GUTIERREZ, O.A., BASU, S., SAHA, S., JENKINS, J.N., SHOEMAKER, D.B., CHEATHAM, C.L., MCCARTY JR, J.C. GENETIC DISTANCE AMONG SELECTED GENOTYPES AND ITS RELATIONSHIP WITH F2 PERFORMANCE. CROP SCIENCE. 2002. V.42.P.1841-1847. Interpretive Summary: Genetic diversity in cotton has a significant impact on crop performance. Relationships between parents and progeny performance have been detected in crops; however, in cotton such information is limited. The purpose of this study was to estimate genetic diversity among selected cotton lines based on simple sequence repeat molecular markers, and to see if there was an association between genetic distance and F2-hybrid performance. Five U.S. and two Australian cultivars and two exotic germplasms were genotyped using 90 SSR primer pairs providing 69 polymorphic marker loci. Genetic distance values showed a lack of genetic diversity among the Australian and U.S. cultivars. Low correlations were obtained between agronomic traits and fiber properties of F2-hybrids and genetic distance values and could not be used for F2 performance prediction due to their association with the genetic background of the germplasm. This research illustrates the need to expand the genetic diversity of cotton germplasm and demonstrates an important role for the use of molecular markers in crop improvement.
Technical Abstract: Knowledge of genetic diversity and relationships among breeding materials has a significant impact on crop improvement. Association between parental divergence and progeny performance has been detected in other crops. However, in cotton (Gossypium hirsutum L.) such studies are limited. The purpose of this study was to estimate genetic diversity among selected cotton genotypes based on SSR markers, and to investigate the relationship between genetic diversity and F2-hybrid performance. Five U.S. and two Australian cultivars and two exotic germplasms were genotyped using 90 SSR primer pairs providing 69 polymorphic marker loci. Genetic distance (GD) between genotypes was calculated and ranged from 0.06 to 0.34 for the 11 parental lines. The highest GD (0.34) was observed between ST474 and the exotic germplasm B1388. The lowest GD (0.06) was detected between Australian cultivars FM832 and FM975. GD between cultivars and exotic germplasm ranged from 0.26 to 0.34. GD among U. S. cultivars varied from 0.10 to 0.22 while GD of Australian cultivars ranged from 0.06 to 0.19 which indicated a narrower genetic base among the Australian cultivars in this study. Significant correlations between agronomic traits and fiber properties of F2 hybrids and GD values were both negative and positive and mostly of low to moderate size. These associations would not be useful for F2 performance prediction because they explain only small portions of the phenotypic variation for important agronomic and fiber quality traits. Results indicated that the correlation between genetic distance and agronomic traits in the F2-hybrids depended on the genetic background.