Fertile Tetraploids: New Resources for Future Rice Breeding?

Yohei Koide,Yuji Kishima,Daichi Kuniyoshi

doi:10.3389/fpls.2020.01231

Abstract

Ploidy manipulation is an efficient technique for the development of novel phenotypes in plant breeding. However, in rice (Oryza sativa L.), severe seed sterility has been considered a barrier preventing cultivation of autotetraploids since the 1930s. Recently, a series of studies identified two fertile autotetraploids, identified herein as the PMeS (Polyploid Meiosis Stability) and Neo-Tetraploid lines. Here, we summarize their characteristics, focusing on the recovery of seed fertility, and discuss potential future directions of study in this area, providing a comprehensive understanding of current progress in the study of fertile tetraploid rice, a classical, but promising, concept for rice breeding.

Highlights

The phenomenon of polyploidy, which refers to the multiplication of chromosome sets within cells, often doubling a normal set into a quadruple set, is a widespread and distinctive feature of the higher plants (Stebbins, 1950)
We focus on autotetraploid rice, especially its fertility, because low seed fertility has been regarded as a barrier obstructing its use
To facilitate the development of fertile autotetraploid lines, further research aimed at understanding the origin of the genes/ quantitative trait loci (QTLs) responsible for high fertility in these tetraploid rice varieties will be necessary

Summary

Introduction

The phenomenon of polyploidy, which refers to the multiplication of chromosome sets within cells, often doubling a normal (diploid) set into a quadruple (tetraploid) set, is a widespread and distinctive feature of the higher plants (Stebbins, 1950). These studies suggested that abnormal chromosomal behavior is one of the reasons for low seed fertility in autotetraploid rice. Its low seed fertility has long been a barrier preventing the use of autotetraploid rice in breeding, two new autotetraploid rice series with high seed and pollen fertilities, identified as the PMeS and Neo-Tetraploid lines, were developed recently (Table 2).

Results

Conclusion