Use of Nodes above White Flower Measurements in Cotton Fertility Studies

J.S. McConnell, W.H. Baker, B.S. Frizzall, and J.J. Varvil


 
ABSTRACT

Maturity and earliness differences in cotton (Gossypium Hirsutum L.) fertility and nutrition experiments due to treatment factors may be difficult to discern. Small plot research forces both the first and second harvests to be conducted when crop maturity is optimum for the entire test rather than any single treatment. The primary estimate of earliness under these conditions is the fraction of the lint gathered in the first harvest or percent first harvest (PFH). Frequently, PFH means are an inadequate method of expressing earliness. The means may have a compressed range or not be significantly different, thereby prohibiting conclusions about the effect of the treatments on maturity.

The number of nodes above white flower (NAWF) has been shown to be an indicator of earliness that is independent of harvest timing or technique. This makes the NAWF method particularly suited to small plot research. NAWF means of each treatment may be used by applying a test for significance (F-test) and a suitable means separation technique for each date. Regression analysis may also be employed. Linear regression of the relationship between NAWF and time for a particular fertilization treatment indicates the speed the plants are approaching maturity. The resulting regression equation may be solved for the time required for the cotton plants to achieve any particular value of NAWF.



Reprinted from 1992 Proceedings Beltwide Cotton Conferences pg. 1182
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998