Peanut Germplasm Evaluation for Agronomic Traits and Disease Resistance under a Two-Season Cropping System in Taiwan

Cultivated peanut (Arachis hypogaea L.) is an important crop worldwide, and peanut germplasm is an important genetic resource for peanut breeding. The two-season cropping system is common in tropical and subtropical regions, which are the main peanut production areas. The weather in the two cropping seasons is usually distinct and makes germplasm evaluation challenging. In this study, random stratified sampling based on market type was applied to build a core collection. Comparisons between the original entire collection and core collection were conducted. Two seasons field trials were performed with additional three seasons rust resistance evaluation trials. Principal component analysis and genotype-by-trait biplots were utilized as selection tools. Which-won-where/what and stability plot relationships were determined to provide breeders with an easy and efficient method for selection. Rust resistance simple sequence repeat and single nucleotide polymorphism markers were used to screen the germplasm. Some resistant accessions showed susceptible phenotypes, indicating that under Taiwan’s environment, the favored rust physiological races are different from those of other areas. Some potential rust resistance lines were discovered and validated, which can survive under variable weather conditions in a two-season cropping system. A set of markers was developed for utilization for rust resistance screening in Taiwan.

Transcriptome-wide Development and Utilization of Novel Intron-length Polymorphic (ILP) Markers in Common Vetch (Vicia Sativa Subsp. Sativa)

Common vetch (Vicia sativa subsp. sativa) is one of the most economically important forage legumes with rich nutritional value and multiple uses. Though the large-scale development and application of microsatellite markers have been conducted in common vetch germplasm evaluation, the investigation and exploitation of intron-length polymorphic (ILP) markers have not been systematically analyzed. In this study, the intron positions of common vetch genome were located by aligning the RNA-Seq sequences of common vetch with Medicago truncatula, soybean (Glycine max), and Arabidopsis thaliana genomic sequences, and used for VsILP marker development. A total of 10,400 markers were generated from 44,582 common vetch unigenes. Out of 300 randomly selected VsILP markers, 283 resulted in successful amplification in common vetch. Among these markers, 40 produced length variation in 30 common vetch accessions, collectively yielding 166 alleles with an average of 4.0 alleles per locus. The polymorphic information content (PIC) values extended from 0.06 to 0.81 with a mean of 0.49. Of the 283 VsILP markers, 84.8% exhibited transferability to leguminous and non-leguminous species. We presented here the first large-scale development of ILP markers in common vetch and their utility in germplasm evaluation and transferability, which will be valuable for further comparative genomic studies, genetic relationship assessments, and marker-assisted breeding of leguminous and non-leguminous species.