2012 Annual Report
1a.Objectives (from AD-416):
Objective 1: Organize, collect data, analyze, and report the NCVT.
Objective 2: Estimate variety (V), environmental (E), and their interaction components (VE) and relate results to improved breeding and evaluation of varieties for specific environments.
Objective 3: Measure the genetic progress in yield, yield components, and fiber traits.
Objective 4: Evaluate variety, environmental, and their variety x environmental contributions of fiber and seed traits that are not usually evaluated in variety tests.
1b.Approach (from AD-416):
Organize and design annual tests, assemble data, analyze, publish and communicate results to cooperators and the public. Archive and make database available to cooperators. Reinforce ARS genetic fiber quality studies. Perform or assist in special variety, years, and location analyses. Update variety evaluations by using the latest technology improvements in computer and statistical services and fiber quality instrumentation. Use NCVT database to detect long term and regional trends in yield and seed and fiber quality. Explore the use of molecular markers (RFLPs) to fingerprint varieties and genetic populations. Utilize database to associate environmental effects on cotton. Utilize residual fiber samples to correlate data from new instrumentation with database. Utilize seed and fiber samples from the NCVT to measure the genetic, environmental, and their interactions on new traits.
The objective of this service project is to establish an organized, flexible system to evaluate cotton varieties’ contributions to the USA cotton industry. The protocol of the National Cotton Variety Test (NCVT) develops and establishes general methods for conducting field tests. The experimental design is a randomized complete block design with four to six replications. A uniform method of reporting data and collecting seed and fiber samples is required. With the exception of the NCVT staff at Stoneville, MS, all of the cooperators are volunteers. These tests involve 14 states organized into six regions (Eastern, Delta, Central, Blacklands, Plains, and Western). Tests are conducted at about 23 locations. A special Regional High Quality Test (RHQ) is conducted in nine states. Pima tests are conducted in Arizona, New Mexico, and California. Tests include measurements for varietal performance on lint and seed yield, seed oil, nitrogen %, gossypol content, and fiber traits such as length, uniformity, micronaire, strength, elongation, brightness and yellowness, yarn tenacity, maturity and fineness. In 2012, 50 varieties/strains were evaluated from 40 specific tests. Data from the NCVT were used by ARS scientists at Stoneville, MS, to measure cultivar stability across the production regions and by a scientist from a commercial cotton breeding organization.
Genetic and environmental contributions to cotton yield. Since changes constantly occur in cotton culture and varieties, analyses of the effects of environments, genotypes and their interactions on cotton yield and fiber traits are needed. A recent study conducted by ARS scientists at Stoneville, MS, and National Cotton Variety Test (NCVT) cooperators and pending publication in The Journal of Cotton Science, analyzed the influence of genotype, environment, and interaction of environment on genotype on the performance of 26 traits using data gathered through the NCVT. Seventy-five to ninety percent of the variation in lint and seed yield, micronaire, and fiber color was largely due to environmental conditions. Thirty to fifty percent of the variation in fiber length, fiber strength and gossypol content in cotton seed was due to each the genotype of the cotton varieties and environmental conditions. Percent total gossypol due to the (+) form of gossypol (a chemical limiting use of cottonseed in animal feed) was mostly under genetic control (72% of variation). Those traits such as lint and seed yield that are largely influenced by environmental conditions require more environments to adequately characterize them (10 or more locations with at least four replications) than those traits such as fiber length and strength that are almost equally influenced by environmental conditions and genotype (about five locations with two replications each).
Dowd, M.K., Boykin, D.L., Meredith Jr, W.R., Campbell, B.T., Bourland, F.M., Gannaway, J.R., Glass, K.M., Zhang, J. 2010. Fatty acid profiles of cottonseed genotypes from the National Cotton Variety Trials. Journal of Cotton Science. 14:64-73.