Recombinant inbred lines derived from cultivars of pea for understanding the genetic basis of variation in breeders' traits

Carol Moreau,Jane Thomas,Claire Domoney,Maggie Knox,Keith Fox,Tracey Rayner,Lynda Turner,Haidee Philpott,Steve Belcher,Noel Ellis

doi:10.1017/s1479262118000345

Abstract

AbstractIn order to gain an understanding of the genetic basis of traits of interest to breeders, the pea varieties Brutus, Enigma and Kahuna were selected, based on measures of their phenotypic and genotypic differences, for the construction of recombinant inbred populations. Reciprocal crosses were carried out for each of the three pairs, and over 200 F2 seeds from each cross advanced to F13. Bulked F7 seeds were used to generate F8–F11 bulks, which were grown in triplicated plots within randomized field trials and used to collect phenotypic data, including seed weight and yield traits, over a number of growing seasons. Genetic maps were constructed from the F6 generation to support the analysis of qualitative and quantitative traits and have led to the identification of four major genetic loci involved in seed weight determination and at least one major locus responsible for variation in yield. Three of the seed weight loci, at least one of which has not been described previously, were associated with the marrowfat seed phenotype. For some of the loci identified, candidate genes have been identified. The F13 single seed descent lines are available as a germplasm resource for the legume and pulse crop communities.

Highlights

As a widely grown pulse crop and one of the oldest domesticated crops, pea (Pisum sativum L.) is grown in many regions of the world
Within the limits of the genetic background of cultivated crops, the three parents were chosen to have contrasting genotypes and phenotypes, the former according to genetic marker analysis and the latter according to available commercial trial data for agronomically important traits
The parents and the recombinant inbred lines (RILs) showed contrasting seed size, a trait of economic importance, with the large block-shaped and somewhat dimpled form of a marrowfat pea seeds being desirable for a variety of food uses

Summary

Introduction

As a widely grown pulse crop and one of the oldest domesticated crops, pea (Pisum sativum L.) is grown in many regions of the world. Pea breeding has achieved many successes in the development. Despite this interest and need, there are many traits in pea for which their genetic basis is poorly understood. Genetics of breeders’ traits in pea and breeding programmes cannot avail of modern technologies to accelerate crop improvement. The key breeding objectives include improving overall yield, yield stability and its components, resistance to biotic and abiotic stresses, as well as enhancing seed quality traits which promote the development of new markets and provide growers with premium returns for their crops. New challenges imposed by climate change, coupled with new regulations regarding seed formulations for disease prevention, are providing additional incentives to crop breeding programmes to diversify the gene pool and to use marker-assisted selection to speed up the introgression of favourable alleles

Methods

Results

Conclusion