Genetic variation for agronomic and fiber properties in an introgressed recombinant inbred population of cotton

Genetic variation available for the improvement of fiber properties is restricted in commercial upland cotton (Gossypium hirsutum L.). Resources for fiber improvement exist in G. barbadense L., but introgression of traits has been a limited success. The objectives of this study were to investigate the genetic variation and heritability of agronomic and fiber traits within a diverse recombinant inbred line (RIL) population created with a stable introgressed parent. The population (n = 98 lines) had as its parents NM24016, a stable G. hirsutum line with significant introgression from G. barbadense, and TM1, the G. hirsutum genetic standard. Yield, plant height, boll size, lint percentage, and fiber length, strength, micronaire, and elongation were measured in randomized., complete block tests at Las Cruces, NM, and Maricopa, AZ, in 2001 and 2002. Genotype coefficients of variation (CV) were highest for plant height and boll size. Among fiber traits, fiber length and micronaire produced the highest genotype CVs. Most traits (fiber elongation excepted) exhibited high broadsense heritability, ranging from 0.69 for lint yield to 0.92 for 2.5% span length. Transgressive segregants were identified for most traits. Fiber strength and 2.5% spun length were favorably correlated (r = 0.59, P = 0.001) as were 2.5% span length and micronaire (r = -0.47, P = 0.001). The NM24016/TM1 RIL population presents valuable genetic variation for fiber quality improvement efforts in G. hirsutum.