Author
McCarty, Jack | |
WU, JIXIANG - MISSISSIPPI STATE UNIV | |
Jenkins, Johnie |
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/9/2005 Publication Date: 6/1/2006 Citation: McCarty, J.C., Wu, J., Jenkins, J.N. 2006. Genetic diversity for agronomic and fiber traits in day-neutral primitive cotton germplasm. Euphytica. 148:283-293. Interpretive Summary: Cotton is an important crop that is grown in warm climates throughout the world. To maintain economic viability cotton yield and quality must be improved. Genetic resources need to be identified and used to enhance important yield and fiber traits. Primitive ancestors of cotton contain diversity for trait improvement; however, many of the accessions have a short-day flowering response and are not readily useable in breeding programs. In this study, 114 accessions selected to flower without being day-length sensitive were evaluated in field trials for two years. Agronomic and fiber trait data were collected and analyzed. Genotypic effects made important contributions to the phenotype indicating genetic diversity among these 114 accessions. A wide range of variation for agronomic and fiber traits were found. Weak genetic relationships were found between yield and fiber length and fiber strength. Although these day-length neutral flowering accessions had lower lint percentage, they had improved fiber length, strength, micronaire, and comparable yields with two cultivars. These accessions are sources of genetic variation that offer the potential to improve important traits and expand genetic diversity. Technical Abstract: Upland cotton (Gossypium hirsutum L) is an important crop that is cultivated in warm climates through-out the world. Agronomic performance and fiber quality must continually be improved if cotton is to maintain economic viability. Genetic resources must be identified and utilized to enhance important traits. Primitive ancestors of cotton contain diversity for trait improvement; however, many of these accessions have a short-day flowering response (photoperiodic) and are not readily useable in breeding programs. In this study, 114 day-neutral derived primitive germplasm lines were evaluated in field trials for two years. Agronomic and fiber trait data were collected and analyzed. Variance components, genotypic values, and genotypic correlations were calculated. Genotypic effects for all traits studied made significant contributions to the phenotypic variation indicating genetic diversity among these lines. The predicted genotypic values showed a wide range of variation for agronomic and fiber traits. Weak genotypic correlations were found between yield and 2.5% span length and fiber strength. Although these day-neutral derived accessions had lower lint percentage, they had improved fiber length, strength, micronaire, and comparable yields with two commercial cultivars. Thus, these day-neutral derived accessions are sources of genetic variation that when used in breeding programs offer the potential to improve important traits and expand genetic diversity. |