ABSTRACT
SUMMARY. This review focuses on the mechanisms determining yield in maize, sunflower and soybean, the three major summer crops of the Argentinean Pampas. Emphasis is given to the capture of light by the crop canopy and the processes determining grain set and grain filling. A strong correlation between grain yield and the physiological status of
crops or plants at crop-specific critical periods is confirmed. This basic physiological information is used (i) to evaluate and understand the ef fect of agricultural management practices on crop yield and (ii) as the source of concepts and quantitative relationships for crop simulation models. Finally, we discuss the relevance of the described physiological processes for crop breeding. [Article copies available fo r a fee from The Haworth Document Delivery Service: I -8OO-HAWORTH. E-mail address: <docdelivery@haworthpress.com> Website: <https://www.HaworthPress.com>; © 2005 by The Haworth Press, Inc. All rights reserved.]
KEYWORDS. Crop management, crop simulation, maize, soybean, sunflower, yield determination
INTRODUCTION
The knowledge of factors and mechanisms that determine crop growth and yield is critical for an efficient and sustainable production because it (i) guides the design and selection of the most appropriate management practices, (ii) provides information for efficient and adequate use of ag ricultural inputs, (iii) provides breeders with the conceptual and screen ing tools that could improve efficiency in the selection of genotypes with high yield potential and adaptation to the target environment and iv) constitutes the conceptual framework for crop simulation models. The first part of the review focuses on the mechanisms determining yield in maize (Zea mays L.), sunflower (Helianthus annus L.), and soy bean [Glycine max (L.) Merr]-the three major summer crops of the Ar gentinean Pampas. Crops with axillary (maize) or apical (sunflower) reproductive sinks, or with sequentially developed fruits (soybean) were analyzed using a common comprehensive and simple conceptual framework. Emphasis is given to the capture of light by the crop canopy and the processes determining grain set and grain filling. A tight corre lation between grain yield and the physiological status of crops or plants at crop-specific critical periods is confirmed. This section is largely based on our own research.
