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Genetic Improvement of Yield, Yield Components, and Agronomic Characteristics of PIMA Cotton: 1949-1991

H. S. Moser and R. G. Percy


 
ABSTRACT

Breeding efforts have made dramatic impacts on the productivity and quality Pima cotton (Gossypium hirsutum L.). Our objectives in this study were to estimate the rate of genetic gain for lint yield, agronomic traits, and fiber quality in Pima cotton from 1949 through 1991 and to determine the changes in yield components associated with increased lint yield in modern Pima cultivars. Eight Pima cotton cultivars developed and released between 1949 and 1991 were included in this study. Pima 32 was released in 1949, Pima S-1 in 1951, Pima S-2 in 1960, Pima S-3 and Pima S-4 in 1966, Pima S-5 in 1975, Pima S-6 in 1983, and Pima S-7 in 1991. All eight cultivars were grown at two locations in Arizona from 1996 through 1998. The locations were chosen to represent low desert (Maricopa) and high desert (Safford) environments. Each cultivar was planted in four or six row plots arranged in an RCB design with four replications. University of Arizona recommendations for cultural practices were followed as closely as possible for each test. The following traits were measured; lint yield, fiber length (2.5% span length), lint percent, uniformity ratio, seed index, fiber strength (stelometer), boll weight, elongation (E1), and micronaire. We analyzed lint yield components of these eight cultivars using the ontogenetic model developed by Worley et al (1976).



Reprinted from Proceedings of the 1999 Beltwide Cotton Conferences pg. 488
©National Cotton Council, Memphis TN

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Document last modified Monday, Jun 21 1999