Crop Establishment in Direct-Seeded Rice: Traits, Physiology, and Genetics

Abstract

AbstractThe changing climate and water availability strongly affect the current state of agricultural production. While the global temperature rises, the occurrence of extreme climatic conditions becomes erratic. This current scenario has driven the development of rice varieties and cultivation practices that require less water and favor mechanization. Although puddled transplanted rice has been more widely used in the past, direct seeding has been gaining popularity in recent years, especially due to its water- and labor-saving features. This technique allows full crop establishment from seeds that were directly sown in the field, thus avoiding puddling, transplanting, and maintaining standing water. Consequently, it offers promising positive environmental effects including decreasing the release of greenhouse gases and increasing water-use efficiency. Historically, rice varieties bred for transplanting are also used in direct seeding, which limits the maximum yield potential of field trials. The success of direct seeding relies strongly on the development of rice varieties with robust crop establishment. Anaerobic germination, seed longevity, and early seedling vigor are the key traits required to achieve this. This chapter expounds on the physiology, molecular mechanisms, genetics, and relevance of the enumerated traits for direct seeding. A brief discussion of breeding for rice varieties with improved germination under direct seeding is also provided.