Assessments of wheat growth to support its production and improvement

Abstract

Eighteen crops of the winter wheat variety Mercia were grown at six locations in 1992-3, 1993-4 and 1994-5, and their development and growth were recorded frequently. The husbandry of these crops aimed to avoid limitations of yield caused by low nitrogen supply, weeds, diseases, pests or lodging through prophylactic use of fertilisers and pesticides, hence attention was focused on effects of site and weather. Techniques of measurement were developed for accuracy and precision. These are presented in Volume II, 'How to Run a Reference Crop' with sufficient detail for interested researchers or groups of cereal growers to assess soil and weather effects at locations representing their own crops. The resultant data have been summarised to provide comparators for many attributes of wheat performance, and the implications for husbandry decisions are outlined. These have been presented in different ways so that (a) through the section entitled 'The Dataset', Volume III, crop scientists can study the variation between sites and seasons in the many interconnected facets of development and growth, and (b) through the section entitled 'The Wheat Growth Digest', practitioners can derive a summary of these same facets against which to compare observations of their own crops. The significance of deviations from the 'norms' is considered in terms of adjustments to husbandry.

Simplified techniques are described to enable wheat growers to assess the most important attributes of individual crops, in 'Methods for In-field Crop Assessment'. In the section entitled 'Forecasting Crop Progress for Wheat', 'look-up' tables are provided to allow the forward prediction of stages of development, green canopy size, crop dry weight , weight per grain, and grain yield. The rules on which these tables are based are presented, and their advantages and deficiencies are discussed.

The general conclusions to the project include an assessment of the potential for the wheat industry of further exploiting this research, and an assessment of the feasibility of undertaking similar research on barley.