Approaches to achieve high grain yield and high resource use efficiency in rice

Jianchang Yang

doi:10.15302/j-fase-2015055

Abstract

This article discusses approaches to simulta- neously increase grain yield and resource use efficiency in rice. Breeding nitrogen efficient cultivars without sacrifi- cing rice yield potential, improving grain fill in later- flowering inferior spikelets and enhancing harvest index are three important approaches to achieving the dual goal of high grain yield and high resource use efficiency. Deeper root distribution and higher leaf photosynthetic N use efficiency at lower N rates could be used as selection criteria to develop N-efficient cultivars. Enhancing sink activity through increasing sugar-spikelet ratio at the heading time and enhancing the conversion efficiency from sucrose to starch though increasing the ratio of abscisic acid to ethylene in grains during grain fill could effectively improve grain fill in inferior spikelets. Several practices, such as post-anthesis controlled soil drying, an alternate wetting and moderate soil drying regime during the whole growing season, and non-flooded straw mulching cultivation, could substantially increase grain yield and water use efficiency, mainly via enhanced remobilization of stored carbon from vegetative tissues to grains and improved harvest index. Further research is needed to understand synergistic interaction between water and N on crop and soil and the mechanism underlying high resource use efficiency in high-yielding rice.

Highlights

Rice (Oryza sativa) is one of the most important food crops in the world, providing 35%–60% of the dietary calories consumed by approximately 3 billion people[1]
It is reported that recovery efficiency of N fertilizer in China is only 30%–35%, which is 15%–20% below that in other major rice growing countries[3,5]
There are reports showing that an alternate wetting and moderate drying regime (AWMD) can significantly decrease ethylene evolution rate and increase the ratio of ABA to ethylene, and enhance the activities of key enzymes involved in sucrose to starch conversion and expressions of the genes encoding enzymes involved in starch synthesis in rice grains[44,45,46]

Summary

Introduction

Rice (Oryza sativa) is one of the most important food crops in the world, providing 35%–60% of the dietary calories consumed by approximately 3 billion people[1]. The national average rice yield was 6.7 t$hm–2 in 2013, which was 56% higher than the world average (4.3 t$hm–2) These great advances in rice production in China have been important for increasing food supply and security. Such advances result partly from high inputs of water and chemical fertilizers especially over-use of nitrogen fertilizer. The questions are whether continuous increases in crop yield can be sustained by simultaneous increases in inputs of water and fertilizer and resource use efficiency. These are contentious issues of agricultural science and remain unresolved[16,17]. This paper discusses approaches to achieve the dual goal of high yield and high resource use efficiency in rice

Breeding N-efficient rice cultivars without sacrificing grain yield potential

Improving grain fill in later-flowering inferior spikelets

Enhancing harvest index to increase grain yield and water productivity

Concluding remarks

Findings

Key points of the techniques