A Comparison of Morphological Maturity Methods in Upland Cotton for the Optimization of Crop Production and Breeding Systems
Type of DegreeMaster's Thesis
Crop Soils and Environmental Sciences
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The indeterminacy of upland cotton (Gossypium hirsutum L.) necessitates methods for evaluating its reproductive status and progress. There is no universally accepted agronomic method for assessing cotton maturity and the method used in a breeding program needs to be quick and efficient within a limitted time frame. In this study, Node of First Fruiting Branch (NFFB), Node above White Flower (NAWF), Node above Cracked Boll (NACB), and visual estimation of percent open (Open) were collected on 16 elite upland cotton varieties at 11 total locations over three years. NAWF, NACB, and Open were each collected twice. Correlations were determined by using the Pearson correlation coefficient. Of all the agronomic maturity methods compared, the first and second measurements of NACB were the most highly correlated. Tukey’s HSD was used to find significant differences between genotypes and genotype’s maturity groupings. NFFB found the most statistical difference between individual genotypes but found no difference in the genotypes when grouped by maturity grouping. High correlation between the second Open and the first NAWF rating suggests Open can be a valuable substitute for the more time consuming NAWF and NACB ratings. This research indicates no one maturity method can fully assess the maturity of a genotype.