Exploring the variability of morphological, agronomic, and fiber quality traits to improve cotton’s response to deficit irrigation

Date

2017-11-13

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Abstract

Producing cotton (G. hirsutum L.) with good yield and high fiber quality has been difficult in the Texas High Plains because of extended periods of inadequate rainfall and the decline of available water for irrigation from the Ogallala Aquifer. Also, little is known about the traits, in a breeding program, to target to improve yield and fiber quality under water limiting conditions. Commercial cultivars and EMS treated obsolete lines were evaluated for the variability in their response to different irrigation rates. By evaluating these two different types of genetic diversity it is hoped that a better understanding of the importance of individual traits are for improving drought tolerance. In 2014 and 2015, nine commercial cultivars representing five companies from the private sector, and from 2014 to 2016 four EMS treated obsolete cultivars were subjected to multiple drip-irrigation water regimes. These genotypes were evaluated based on the differences in their response to deficit irrigation in a variety of morphological (13), agronomic (4), and fiber quality (5) traits. Analyses of these traits showed differences between genotypes and irrigation rates. Both sources of genetic diversity showed some similarities with larger differences in genetic potential being observed in the high irrigation rate. Also, the fiber quality traits of micronaire, length, and strength were the most impacted by irrigation. However, there were also differences observed between the two sources of diversity. For the commercial cultivars, the fiber quality traits showed the impact of irrigation more than any other traits measured. However, for the EMS treated obsolete cultivars more impact of irrigation was observed in the morphological traits. This indicates that multiple types of diversity may be required to improve the response (yield and fiber quality) of cotton to deficit irrigation or drought stress. Germplasm and commercial cultivars that can sustain yield and superior fiber quality under water limited conditions is essential for the long-term survival of the cotton industry in the Texas High Plains.

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Keywords

cotton, breeding, drought

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