Abstract:
This “research highlight” addresses the crucial need for breeding high-yielding, climate-smart and stable wheat and barley varieties with desirable traits such as early flowering, high yield, stability and enhanced kernel characteristics for dry areas. Every year the UJ-Small Grains Breeding Program evaluates hundreds of wheat and barley genotypes produced from crosses between elite varieties and local Jordanian landraces. The produced material is evaluated across different environments across the country. Furthermore, modern molecular tools are applied to enable the precise selection of genetic material carrying the desirable traits and for the mapping of QTLs associated with them. The outcomes of this program offer valuable insights for wheat and barley breeders aiming to develop high-yielding and stable varieties for dry areas, with many of them standing out as a promising choice for farmers in dryland farming systems.
UJ-Small Grains Breeding Program (Season 2022-2023).
Significance:
Wheat (Triticum spp.) and barley (Hordeum vulgar) are considered two important cereal crops for humans. Durum wheat and barley are the crops of choice in the Mediterranean region and dry areas and they are commonly used in diverse products. Nowadays, there is a worldwide trend to consume durum wheat and barley products due to their substantial contribution to nutritious dietary habits. Climate change, especially drought and heat extremes, poses a threat to small grain production. This “research highlight” underscores the importance of plant breeding programs, especially molecular plant breeding, as a promising approach to enhance wheat and barley yield under changing climatic conditions. It emphasizes the need for identifying genes and genetic networks underlying yield and yield components and stability under drought and saline conditions.
The NUR-106 breeding line at UJ agricultural research station during 2021-2022 season.
Highlights:
Understanding the genetic basis of grain-related traits is crucial for developing improved durum wheat varieties for both yield and quality in dry environments. The presented results highlight the significance of breeding high-yielding and stable durum wheat varieties, particularly those with improved kernel characteristics, using Jordanian durum wheat landraces to address the challenges of dry regions worldwide. The focus of this study is to highlight the importance of kernel weight, especially the thousand kernel weight (TKW), for future yield improvement using Jordanian durum wheat landraces.
The research highlights the complexity of TKW as influenced by multiple kernel-related traits, and stresses the need to understand the genetic basis of kernel attributes such as width, length, and area. The study identified specific durum wheat genotypes, such as Um Qais, Bolenga and NUR-106, that produced high GY across diverse environments. NUR-106, a recombinant inbred line (RIL) derived from a cross between Norsi and “Desert King”, emerged as a superior line that aligns with the quest for heavier golden grains and a stable genotype for dry farming systems. NUR-106 will be utilized in ongoing efforts including breeding programs, high-input systems, and conservation practices to enhance yield potential.
Kernels features of six selected durum wheat genotypes including NUR-106.
For QTL mapping, a RIL population (derived from a cross between Norsi and “Desert King” with 256 individuals) genotyped using the 15K SNP array was assessed across seven environments. All studied traits exhibited high heritability and significant genotypic effects, prompting QTL mapping for individual environments and a multi-environment trial (MET) using combined data analysis. The mapping analysis identified 95 QTLs in the field environments and 325 in the multi-environment trial across all 14 chromosomes of the durum wheat genome.
Norsi x UC1113 linkage map showing location of SNP markers on chromosomes of the A genome.
For barley, genetic diversity and yield performance in Jordanian landraces grown under rainfed conditions were assessed. Superior genotypes were identified by understanding “genotype by environment” interactions, and analyzing different stability parameters. The genetic analysis revealed that the landraces were diverse and clustered based on the row type. Genome-wide association mapping was employed and molecular markers associated with yield and yield components were identified.
Genome wide association mapping of major flowering time using a set of 150 barley accessions grown under different environments across Jordan.
In addition, early flowering and drought-tolerant Jordanian barley landraces were identified and used in the breeding program to improve barley cultivars for dry regions. A promising barley breeding line, called UJ-BC4F4, was developed using the local cultivar Mutah following a backcross breeding scheme and deployment of a perfect molecular marker used for marker assisted selection. The new breeding line proved to be a high-yielding and superior-stable genotype when cultivated across different environments in Jordan.
Upper: The UJ-BC4F4 breeding line at UJ agricultural research station during 2021-2022 season. Lower: GGE-biplot and stability analysis for the grains yield traits for 25 genotypes tested across seven environments.
Conclusion:
The highlighted research reveals the promise of Jordanian wheat and barley germplasm for addressing yield and stability challenges in dry environments. Identifying superior genotypes, like NUR-106 and UJ-BC4F4, verify that utilizing Jordanian germplasm for breeding high-yielding, stable wheat and barley varieties with robust yield characteristics is possible. NUR-106, in particular, stands out as a shining example of the quest of UJ small grains breeding program for the generation of "heavier golden durum grains," perfectly suited for sustainable agriculture in dry regions. UJ-BC4F4 is a good example for accelerating the barley life cycle while maintaining high yield in dry areas across the region. Our findings open exciting avenues for further research, including new breeding activities, modern and smart agriculture practices, and conservation initiatives, to unlock the immense potential of Jordanian landraces to nourish populations worldwide.
Prof. Ayed Al-Abdallat is a leading plant scientist affiliated with the UJ-Research In Plant sciencE (RIPE) group.