Estimating the Leaf Area of Cotton (Gossypium hirsutum L.) Plants by Means of Relationships between Monopodial and Sympodial Leaves

Aims: Relationships between areas of monopodial and sympodial leaves reported in the literature suggest a consistent size gradient among leaves along the sympodial branches of cotton plants. The objective of this study is to assess how well a non-destructive procedure based on these relationships can estimate leaf area of cotton plants.

Study Design: Randomized complete block with 6 replications.

Place and Duration of Study: The study was conducted in the Drought Tolerance Laboratory at the Texas A&M AgriLife Research and Extension Center near Corpus Christi, TX and at the Texas AgriLife Field Laboratory in Burleson County located 12.9 km west of College Station, TX between February 2014 and July 2015.

Methodology: In 2014, plants from four different cultivars were sampled at the Drought Tolerance Laboratory at the Texas A&M AgriLife Research and Extension Center at Corpus Christi in order gather data to develop the methodology. Four cotton cultivars included PHY 375, PHY499, DPL912, and DPL1044. The inclusion of four cultivars had the purpose of incorporating variability in the data to be used for developing the empirical model to estimate WPLA, thus making it more robust. In 2015, field- and lab-grown plants were sampled to evaluate the accuracy of the non-destructive method to estimate whole-plant leaf area.

Results: The results indicated that the methodology overestimated the leaf area of the field-grown plants, while underestimated that of lab-grown plants. However, estimated vs. observed deviations from the 1:1 line were not significant.

Conclusion: It is concluded that despite inconsistencies in leaf area ratios across sympodial branches, the non-destructive method developed still has the potential to be utilized to estimate the leaf area of cotton plants when no leaf area measurement equipment is available.