Jean-Yves Hoarau

Cirad - La recherche agronomique pour le développement | CIRAD · UMR AGAP (Genetic Improvement and Adaptation of Mediterranean and Tropical Plants)

Sugarcane, the world’s most harvested crop by tonnage, has shaped global history, trade and geopolitics, and is currently responsible for 80% of sugar production worldwide¹. While traditional sugarcane breeding methods have effectively generated cultivars adapted to new environments and pathogens, sugar yield improvements have recently plateaued²....

Key message Six QTLs of resistance to sugarcane orange rust were identified in modern interspecific hybrids by GWAS. For five of them, the resistance alleles originated from S. spontaneum. Altogether, they efficiently predict disease resistance. Abstract Sugarcane orange rust (SOR) is a threatening emerging disease in many sugarcane industries wor...

Orange rust caused by Puccinia kuehnii is a major emerging disease in many sugarcane-producing countries. Breeding for resistant varieties is the main strategy for controlling orange rust. The rapid spread of this disease in recently contaminated sugarcane industries offers the opportunity to use on-going breeding trials to investigate the effect o...

Yellow sugarcane aphid, Sipha flava (Forbes) (Hemiptera: Aphididae), widely distributed throughout the Americas and invasive in Africa, has been detected in Réunion Island since 2017. This insect causes damages to several crop species, including sugarcane (Saccharum spp.). On sugarcane, yellow to purple discoloration of leaves are frequently observ...

The use of linear mixed models (LMM) and its Best Linear Unbiased Prediction (BLUP) methodology is becoming increasingly popular amongst research scientists dealing with data modelling. Development of computer power and user-friendly statistical software facilitate their rapid implementation. This paper gives an overview of the benefits of the flex...

Sugarcane breeding programs aim to deliver new high-yielding varieties, resistant to diseases and pests, which contribute to profitability and sustainability of cane industries. These programs generally mobilize significant experimental, technological and human resources on long-term basis. Their efficiency in terms of genetic gains per unit of cos...

All over the world, sugarcane breeding programs are developing new, high-yielding cultivars that are resistant to major diseases to improve the profitability and sustainability of the sugar-energy industries they serve. In Reunion Island, sugarcane genetic improvement efforts began in 1929. Many challenges had to be overcome. Continuous breeding ef...

Sugarcane variety development programmes are costly and lengthy. It appears important to periodically assess their ability to select competitive genotypes for yield components and provide genetic gains. This article reports a 10-year retrospective analysis of successive variety trials conducted in four regional breeding programmes on Réunion Island...

Multi-environment trials (METs) represent the final stage of breeding programs prior to the commercial release of new varieties. Optimized analysis of METs impact genetic gains subsequently delivered to cane growers. The information provided by METs can be large and therefore complex to analyze and interpret when considering many environments of se...

eRcane currently operates in Reunion several decentralized concurrent sub-selection progr'ammes located in the major areas under cane differing in their agro-climatic conditions. Each year about 100,000 new seedlings are dispatched among the different sub-programs which receive mainly the same families. This early decentralized scheme of selection...

Sugarcane yellow leaf virus (SCYLV) can infect many modern sugarcane varieties and cause insidious yield losses in susceptible cultivars. Information about the heritability of resistance to SCYLV is useful in designing appropriate breeding strategies likely to generate genetic gains and develop resistant varieties. This study aimed at computing qua...

The sugarcane variety development program on Réunion Island is dedicated to an industry that encompasses numerous different agroclimatic production zones. The objective of this study is to characterize in detail the final selection stage of this program, consisting of multienvironment trials (MET) at seven representative locations, considering the...

This study tested strategies for the prediction by NIRS of the chemical composition and nutritive value of large poaceae (sorghum, millet, sugarcane, miscanthus etc.). The main objective was to evaluate the possibility of prediction of samples when no specific calibration is available because the plant part of the species is not com-mon enough. The...

Sugarcane cultivars are interspecific hybrids with an aneuploid, highly heterozygous polyploid genome. The complexity of the sugarcane genome is the main obstacle to the use of marker assisted selection in sugarcane breeding. Given the promising results of recent studies of plant genomic selection, we explored the feasibility of genomic selection i...

Key message: Using GWAS approaches, we detected independent resistant markers in sugarcane towards a vectored virus disease. Based on comparative genomics, several candidate genes potentially involved in virus/aphid/plant interactions were pinpointed. Yellow leaf of sugarcane is an emerging viral disease whose causal agent is a Polerovirus, the Su...

Sugarcane cultivars are interspecific hybrids with an aneuploid, highly heterozygous polyploid genome. The complexity of the sugarcane genome is the main obstacle to the use of marker-assisted selection in sugarcane breeding. Given the promising results of recent studies of plant genomic selection, we explored the feasibility of genomic selection i...

This chapter reviews the sugarcane evolution and breeding history that led to the present-day cultivar genomes (Saccharum spp.), and summarizes yield improvement. It discusses the genomic tools developed for sugarcane genome analyses, their potential applications. The chapter talks about the challenges involved in the usage of genomic tools for yie...

Sugarcane cultivars are interspecific hybrids with an aneuploid, highly heterozygous polyploid genome. The complexity of the sugarcane genome is the main obstacle to the use of marker-assisted selection in sugarcane breeding. Given the promising results of recent studies of plant genomic selection, we explored the feasibility of genomic selection i...

Modern sugarcane cultivars (Saccharum spp., 2n = 100-130) are high polyploid, aneuploid and of interspecific origin. A major gene (Bru1) conferring resistance to brown rust, caused by the fungus Puccinia melanocephala, has been identified in cultivar R570. We analyzed 380 modern cultivars and breeding materials covering the worldwide diversity with...

The spotted stem borer (SSB) Chilo sacchariphagus is a major pest of sugarcane, causing substantial losses in cane weight and in sucrose yield. SSB resistance is an important trait to be taken into account for sugarcane breeding programs. In order to analyse the genetic basis of the resistance to SSB, we undertook a quantitative trait allele (QTA)...

Les cultivars modernes de canne à sucre (Saccharum spp., 2n=100 à 130) sont hautement polyploïdes, aneuploïdes et d'origine interspécifique. Un gène majeur (Bru1) conférant la résistance à la rouille brune, causée par le champignon Puccinia melanocephala, a été identifié chez le cultivar R570. Nous avons analysé 380 cultivars modernes et clones en...

Modern sugarcane cultivars (Saccharum spp., 2n = 100-130) are high polyploid, aneuploid and of interspecific origin. A major gene (Bru1) conferring resistance to brown rust, caused by the fungus Puccinia melanocephala, has been identified in cultivar R570. We analyzed 380 modern cultivars and breeding materials covering the worldwide diversity with...

As sugarcane is a complex polyaneuploid with many chromosomes, large numbers of markers are required to generate genetic maps with reasonable levels of genome coverage. Comparative mapping was investigated as an approach for both quantitative trait loci (QTL) validation and genetic map enhancement in sugarcane. More than 1000 SSR and AFLP markers w...

RESUME L'amélioration variétale est une voie privilégiée pour accroître la durabilité des productions agricoles. Elle répond aux attentes des agriculteurs pour faire face aux contraintes biotiques, abiotiques et socio-économiques. Elle contribue à la pérennisation et à l'intensification des productions et permet de répondre à une compétitivité cr...

Sugarcane genetic improvement techniques

Modern sugarcane cultivars (Saccharum spp) are highly polyploïd and aneuploid interspecific hybrids (2n = 100-130). Two genetic maps were constructed using a population of 198 progeny from a cross between R570, a modern cultivar, and MQ76-53, an old Australian clone derived from a cross between Trojan (a modern cultivar) and SES528 (a wild Saccharu...

Mandalay is an important Saccharum spontaneum clone used historically in Australian sugarcane breeding programs, and has given rise to many valuable cultivars. In order to better understand the genetic contribution of Mandalay to Australian varieties and elite parental material, a combined pedigree and quantitative trait loci (QTL) mapping approach...

The presence of a major resistance gene (Bru1) for brown rust in the sugarcane cultivar R570 (2n about 115) was confirmed by analyzing segregation of rust resistance in a large population of 658 individuals, derived from selfing of clone R570. A subset of this population was analyzed with AFLP and bulked segregant analysis (BSA) to develop a detail...

Phosphoenolpyruvate carboxylases (PEPCs) are encoded by a small multigenic family. In order to characterise this gene family in sugarcane, seven DNA fragments displaying a high homology with grass PEPC genes were isolated using polymerase chain reaction-based cloning. A phylogenetic study revealed the existence of four main PEPC gene lineages in gr...

A Quantitative Trait Locus (QTL) mapping study is under way to analyse the genetic determinism underlying sugarcane smut resistance. A total of 1295 polymorphic AFLP markers have been generated on a population of 200 individuals derived from a cross between R 570 (resistant) and MQ 76/53 (highly susceptible). This population is under evaluation for...

The genetics of current sugarcane cultivars ( Saccharum spp.) is outstandingly complex, due to a high ploidy level and an interspecific origin which leads to the presence of numerous chromosomes belonging to two ancestral genomes. In order to analyse the inheritance of quantitative traits, we have undertaken an extensive Quantitative Trait Allele (...

Sugarcane mosaic disease was introduced in Réunion island in the early XXth century. Considerable economic losses were recorded at the end of the twenties, mainly in the West and the South parts of the island where the epidemic had sprayed everywhere. This alarming situation persuaded the Sugar Milling Association to create the Genetic Station of...

Résumé Dans un contexte de compétition internationale croissante, chaque pays producteur de canne à sucre cherche à améliorer ses rendements agricoles, dans une perspective de développement durable visant à maintenir le revenu des planteurs. L'augmentation des rendements passe souvent par la culture de nouvelles variétés plus productives qui procu...

Sugarcane cultivars are polyploid, aneuploid clones derived from interspecific hybridization between Saccharum officinarum and S. spontaneum. Their genome has recently started to be unravelled as a result of the development of molecular markers. We constructed an AFLP genetic map based on a selfing population of a specific cultivar, R570.Using 37 A...

Smut is one of the most important diseases of sugarcane and has a worldwide distribution. It can cause severe yield losses when a susceptible variety is grown in a smut infested area. Resistance is therefore a major concern for most sugarcane breeding centers. A study on the genetic determinism underlying sugarcane smut resistance was initiated. A...

Inheritance of resistance to rust was investigated in the self progeny of the sugarcane cultivar 'R570' also used to build a RFLP genetic map. Resistance was evaluated through both field and controlled greenhouse trials. A clear-cut 3 (resistant) ∶ 1 (susceptible) segregation indicative of a probable dominant resistant gene was observed. This is th...