Cytogenetic and agronomic characterization of intergeneric hybrids between Saccharum spp. hybrid and Erianthus arundinaceus

Babil Pachakkil,Hiroko Takagi,Shin Irei,Hisayoshi Hayashi,Nobuko Ohmido,Masumi Ebina,Yoshifumi Terajima

doi:10.1038/s41598-018-38316-6

Abstract

In sugarcane (Saccharum spp. hybrid) breeding, introgression of useful genes via intergeneric hybridization is a powerful strategy for improving the crop productivity. Erianthus arundinaceus shows great potential in terms of useful traits; however, little is known about the cytogenetic and agronomic characteristics of intergeneric hybrids between these two species. Here, we examine the cytogenetic and agronomic characteristics, and relationships between the two in intergeneric F1 hybrids between modern sugarcane cultivar and E. arundinaceus identified by amplification of 5S rDNA markers and morphological characteristics. The nuclear DNA content of the hybrids varied from 6.07 to 8.94 pg/2C, with intra-clonal variation in DNA content and 5S rDNA sites. Genomic in situ hybridization revealed 53 to 82 chromosomes in the hybrids, with 53 to 56 derived from sugarcane and 1 to 29 from E. arundinaceus. There were significant positive correlations between the number of E. arundinaceus chromosomes and dry matter yield, millable stalk weight, single stalk weight, and stalk diameter, but not sucrose content, reducing sugar content, sucrose/reducing sugar ratio or fiber content. This detailed information on intergeneric F1 hybrids between modern sugarcane cultivar and E. arundinaceus will contribute to effective utilization of E. arundinaceus in sugarcane breeding.

Highlights

Sugarcane is an economically important crop with worldwide production of 1.9 billion tons[1], accounting for two-thirds of the world’s sugar production and providing feedstocks for bio-energy production
Despite displaying no bands corresponding to the Erianthus 5S ribosomal DNA (5S rDNA) spacer, ‘J09-2’ and ‘J11-12’ were identified as possible intergeneric hybrids because of their morphological appearance, which was very similar to the other hybrids
Despite the potential of E. arundinaceus as germplasm aimed at broadening the genetic base and introducing new genes into sugarcane breeding, the cytogenetic and agronomic characteristics of resulting intergeneric hybrids have yet to be described in detail, and little is known about the relationships between these characteristics

Summary

Introduction

Sugarcane is an economically important crop with worldwide production of 1.9 billion tons[1], accounting for two-thirds of the world’s sugar production and providing feedstocks for bio-energy production. Polyploid (2n = 100–130) modern sugarcane cultivars (Saccharum spp. hybrid) were derived via complex interspecific crosses between the sugar-producing species S. officinarum (2n = 10x = 80) and the wild species S. spontaneum (2n = 40–128). This interspecific hybridization, which was first performed a century ago, plays a major role in improving yield, disease resistance, and adaptability to abiotic stresses in sugarcane cultivars. Despite the importance of the Erianthus germplasm in sugarcane breeding, the large genetic distance between Saccharum and Erianthus results in cross-incompatibility[6,7,8], a major constraint in generating intergeneric hybrids. The cytogenetic characteristics of intergeneric hybrids between S. officinarum and E. arundinaceus have been extensively examined, there has been little progress in the characterization of intergeneric hybrids between modern sugarcane cultivars and E. arundinaceus

Methods

Results

Conclusion