Genotypic differences in red clover (Trifolium pratense L.) response under severe water deficit

Abstract

AimsIn Ontario, Canada, acreage of red clover (Trifolium pratense L.) intercropped with winter wheat (Triticum aestivum L. em. Thell) has declined, despite well-documented soil and yield benefits. The decline has resulted from increasing prevalence of stand non-uniformity, which has been attributed in part to soil moisture deficits. We examined whether there are genotypic differences in drought response between red clover varieties.MethodsA double-cut (Belle) and a single-cut variety (Altaswede) were grown under four different durations of drought (4, 8, 12 and 16 days below 15% relative soil water content, RSWC). Shoot dry weight, shoot relative water content (RWC), leaf area and crown water content were measured in control, drought and drought + recovery treatments.ResultsBelle used significantly more water during soil moisture deficit and had greater leaf area, shoot dry weight and RWC compared to Altaswede. In contrast, Altaswede had significantly higher survival rates than Belle, attributed to maintenance of meristematic tissue viability in the crown where re-growth, after shoot tissue desiccation, can occur.ConclusionsBy demonstrating genotypic variation in survival strategies of red clover, traits can be identified for the development of improved varieties. Varieties with higher survival rates during drought will result in more uniform stands and increased utilization of red clover for environmental and yield benefits.