Analysis of allele diversity for improvement of nutritional profile and disease resistance in pea.

Development of cultivars with improved nutritional profile and agronomic characters are among the major objectives in field pea breeding at the Crop Development Centre (CDC). Genetic diversity among parental lines contributes significantly to progress in developing new crop cultivars. Currently the CDC pea breeding program utilizes Canadian cultivars and germplasm from western Europe, Australia and the United States as parents in breeding. Germplasm from eastern Europe and Russia has not been exploited in the CDC or other Canadian breeding programs, thus, this germplasm presents interesting possibilities to enhance pea breeding.

In this project, 169 pea accessions of the cultivated pea Pisum sativum,  wild relative species P. fulvum and several wild sub-species accessions (subspp. abyssinicum, arvense, and elatius) collected from eastern Europe, Russia and Canada were screened for their nutritional profile including total starch, amylose, amylopectin, fiber and protein by wet chemistry and/or near infrared (NIR) methods, and for reaction to ascochyta blight under controlled and/or field conditions. Primer pairs for 22 candidate genes affecting carbohydrate metabolism, protein deposition and ascochyta blight resistance were selected (Aubert et al. 2006, Prioul-Gervais et al. 2007). These primers were used to amplify DNA fragments from 56 accessions selected based on their diverse phenotypic performance (high/low) from the initial screening of 169 accessions, and allele variants for these genes  were detected by sequencing the PCR products using primers designed to amplify the intronic region of the candidate genes. Selected accessions were sequenced at all 22 candidate genes to identify single nucleotide polymorphisms (SNPs). These SNPs will be integrated to previous maps, i.e.,  from Carneval x MP1401 (Tar’an et al. 2003) and from Orb x CDC Striker (Ubayasena et al. 2010). Allele variation within the candidate genes across the pea genotypes will be correlated to their phenotypic values. Germplasm accessions with desirable profiles will be used in the pea breeding program. The SNP markers developed in this project will facilitate the marker assisted selection program to incorporate the diverse alleles into improved pea cultivars.