Genetics of pre-harvest sprouting resistance in a cross of Canadian adapted durum wheat genotypes

A K Singh,R E Knox,R M Depauw,J M Clarke,R D Cuthbert,F R Clarke,A Singh

doi:10.1007/s11032-013-0006-y

Abstract

Severe losses attributable to pre-harvest sprouting (PHS) have been reported in Canada in recent years. The genetics of PHS resistance have been more extensively studied in hexaploid wheat and generally not using combinations of elite agronomic parents. The objective of our research was to understand the genetic nature of PHS resistance in an elite durum cross. A doubled haploid (DH) population and checks were phenotyped in replicated trials for grain yield and PHS traits over 3 years in western Canada. The response of intact spikes to sprouting conditions, sampled over two development time points, was measured in a rain simulation chamber. The DH population was genotyped with simple sequence repeat and Diversity Arrays Technology markers. Genotypes were a significant source of variation for grain yield and PHS resistance traits in each tested environment. Transgressive segregant DH genotypes were identified for grain yield and PHS resistance measurements. Low or no correlation was detected between grain yield and PHS, while correlation between PHS resistance measurements was moderate. The heritability of PHS resistance was moderate and higher than grain yield. Significant quantitative trait loci with small effect were detected on chromosomes 1A, 1B, 5B, 7A and 7B. Both parents contributed to the PHS resistance. Promising DH genotypes with high and stable grain yield as well as PHS resistance were identified, suggesting that grain yield and PHS can be improved simultaneously in elite genetic materials, and that these DH genotypes will be useful parental material for durum breeding programs.

Highlights

Pre-harvest sprouting (PHS) refers to germination of seeds in physiologically mature spikes prior to harvest
Genotypes were a significant source of variation for grain yield, T1HS, T2HS, T1KS and T2KS in each tested environment (Table 1)
The results of transgressive segregation, moderate heritability and correlations among measures, differences in pre-harvest sprouting (PHS) resistance between sampling times and years, and multiple quantitative trait loci (QTL) provide evidence that PHS resistance is under complex genetic control within the DT707/DT696 population

Summary

Introduction

Pre-harvest sprouting (PHS) refers to germination of seeds in physiologically mature spikes prior to harvest. In Canada, PHS is reported to be a problem during wet or humid harvest conditions (McCaig and DePauw 1992). Severe losses were reported in three (2000, 2002 and 2010) of the past 10 years (Clarke et al.2005a; Knox et al 2012). The economic impact of PHS occurs through losses in grain yield, test weight, grain functionality and viability of seed for planting (Belderok 1968; Buchanan and Nicholas 1980; Czarnecki and Evans 1986; Derera 1989). Samples with more than 0.5 % sprouted kernels are downgraded from a Canada Western Amber Durum (CWAD) No 1 to CWAD No 2, causing economic losses to producers, and more severe downgrading often occurs

Objectives

Methods

Results

Conclusion