Development and Proof-of-Concept Application of Genome-Enabled Selection for Pea Grain Yield under Severe Terminal Drought.

Paolo Annicchiarico,Meriem Laouar,Massimo Romani,Imane Thami-Alami,Nelson Nazzicari,Luciano Pecetti

doi:10.3390/ijms21072414

Abstract

Terminal drought is the main stress limiting pea (Pisum sativum L.) grain yield in Mediterranean environments. This study aimed to investigate genotype × environment (GE) interaction patterns, define a genomic selection (GS) model for yield under severe drought based on single nucleotide polymorphism (SNP) markers from genotyping-by-sequencing, and compare GS with phenotypic selection (PS) and marker-assisted selection (MAS). Some 288 lines belonging to three connected RIL populations were evaluated in a managed-stress (MS) environment of Northern Italy, Marchouch (Morocco), and Alger (Algeria). Intra-environment, cross-environment, and cross-population predictive ability were assessed by Ridge Regression best linear unbiased prediction (rrBLUP) and Bayesian Lasso models. GE interaction was particularly large across moderate-stress and severe-stress environments. In proof-of-concept experiments performed in a MS environment, GS models constructed from MS environment and Marchouch data applied to independent material separated top-performing lines from mid- and bottom-performing ones, and produced actual yield gains similar to PS. The latter result would imply somewhat greater GS efficiency when considering same selection costs, in partial agreement with predicted efficiency results. GS, which exploited drought escape and intrinsic drought tolerance, exhibited 18% greater selection efficiency than MAS (albeit with non-significant difference between selections) and moderate to high cross-population predictive ability. GS can be cost-efficient to raise yields under severe drought.

Highlights

The combined effect of population growth, change and instability of climate, reduced available irrigation water, land degradation, and inefficient and environment-unfriendly exogenous nitrogen inputs are threatening the global food security [1,2,3]
The interaction was high between Alger—which could be defined as a moderate-stress environment according to the yield value around 3.3 t/ha observed for top-performing material—and the other two environments—whose yield of top-performing material was below 1 t/ha—as indicated by genetic correlations close to zero and contrasting environment ordination on genotype × environment (GE) interaction principal component (PC) 1
A limitation of this study was the lack of repetition in time of the experiments in the two agricultural locations, which did not allow to assess the extent of within-site GE interaction and mean yield variation and to verify the close relationship between environment similarity for GE interaction pattern and environment mean yield that was suggested by the results

Summary

Introduction

The combined effect of population growth, change and instability of climate, reduced available irrigation water, land degradation, and inefficient and environment-unfriendly exogenous nitrogen inputs are threatening the global food security [1,2,3]. Greater cultivation of drought-tolerant, resilient legume crops would represent a key asset for facing these challenges, by increasing the sustainability of agriculture in terms of soil fertility, energy efficiency, greenhouse gas emissions, pollution, and crop diversity on the one hand and the efficiency and quality of food systems on the other [4,5,6]. This is especially true for countries of Europe and Northern Africa, where greater legume cultivation is required to decrease their huge dependency on international markets for high-protein feedstuff [7,8]. Recent work highlighted high potential interest and farmers’ appreciation for pea in North-African environments, too [16]

Objectives

Methods

Results

Conclusion