Submitted to: World Cotton Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/9/2003
Publication Date: 5/1/2004
Citation: McCarty Jr, J.C., Jenkins, J.N., Wu, J. 2004. Primitive accessions of cotton as genetic sources for improving yield and fiber properties. World Cotton Research Conference Proceedings. p. 114-118.
Interpretive Summary: Fiber quality and lint yield of cotton must be increased to meet textile mill and grower demands. Primitive or wild cottons contain a broad range of variability for useful traits. Many of the primitive cottons will not flower during the summer growing season because their flowering depends on a long dark to short light time period. Plants that flower regardless of the length of the dark to light time period are called day-neutral. Day-neutral plants have been selected in the primitive cottons. A study was conducted to measure yield and fiber quality when fourteen day-neutral cottons with high fiber strength were crossed to each of five commercial varieties. The second generation hybrids and the parents were grown in two field locations in 1998 and 1999. Parents and third generation hybrids were grown in two locations in 2000. Yield and fiber quality traits were affected by the year and location in which they were grown. The varieties produced more yield, had larger bolls and higher lint turn-out than the primitive cottons. Fiber strength for primitive cottons exceeded that of varieties. Lint turn-out, boll size, fiber fineness, and fiber length were similar between the second and third generation hybrids. Yield was not closely related between second and third generation hybrids. Lint turn-out, fiber length and fiber strength were strongly influenced by genetic make-up; whereas yield and boll size were influenced by environment. This study will contribute to the understanding and use of primitive cottons.
Technical Abstract: The breeding of cotton, Gossypium hirsutum L., to improve lint yield and fiber quality is an on going process. To meet textile mill requirements and producer demands both fiber quality and lint yield must be increased. The U. S. collection of primitive cotton accessions contains a broad range of variability for pest resistance and agronomic traits; however, because many of the accessions are photoperiodic, this variability is not readily useable by plant breeders. Day-neutral selections have been made that contain variability for agronomic and fiber traits. A study was conducted to evaluate yield, yield components and fiber quality traits when fourteen day-neutral lines derived from selected primitive accessions with high fiber strength were crossed as male parents to each of five commercial cultivars. The F2 hybrids and parents were grown in two different field locations in 1998 and 1999; whereas, the F3 hybrids and parents were grown in two locations in 2000. Combination of locations and years were considered as environments for data analyses. All traits measured were significantly affected by environment with genotype by environment interactions. The cultivars produced more yield, had larger bolls and higher lint percentages than the accession derived male parents. Fiber strength for male parents exceeded that of cultivars. The mean lint yield for F2 and F3 hybrids exceeded the mid-parent value within each environment. Lint percentage, boll size, micronaire, elongation, and fiber length were similar between F2 and F3 hybrids. Most traits were highly correlated between F2 and F3 generations; however, seed cotton yield and lint yield were not correlated between F2 and F3. Genetic variance component analyses revealed that additive, dominance, and additive by additive epistasis effects were significant for most traits measured. Additive effects were important for controlling lint percent, fiber length and fiber strength; whereas, dominance effects were important for yield and boll size. This study will contribute to the use of primitive accession germplasm in cotton breeding programs.