Phenological development of cotton plants can be quantified by summarizing plant map data. Research experiments require plant maps describing the distribution of all reproductive structures to properly assess the effect of the treatments. Summarizing such data requires tedious arithmetic computations. For this reason computers are well-suited to perform the task. This presentation describes a computer program designed to facilitate the input, analysis and interpretation of a large number of individual plant maps. The program, written in FORTRAN, uses a commercial graphics library for the display of data entry windows and output data. As currently configured, the data can be displayed graphically on the screen in ten different formats. The different formats or windows are selected by the user by pressing the function keys of the keyboard. The plant map program has been helpful in detecting and illustrating the effects of PIX and soil moisture supply on the reproductive load of cotton plants. The program has also being successfully used to study phenological differences among MAR and Delta type cultivars.

Knowledge of the phenological stages of crop development is essential for the proper management of inputs such as irrigation, fertilizers, insecticides, growth regulators and harvest aids. The use of plant map summaries as a management tool is gaining acceptance by researchers and producers. Proper interpretation of the data however is difficult. The difficulty arises from the lack of knowledge on the relation between the fruit and square load during the early stages of plant development and final lint yield. The difficulty is further confounded by the uncertainty of weather events. We propose the use of model plant maps representing crops of various yield potentials as "targets" to guide the in-season decision making process. Research on the use of plant map data to make in-season management decisions is needed.