Impact of seed discolouration on emergence and early plant growth of durum wheat at different soil gravimetric water contents

Abstract

The effects of soil gravimetric water content on emergence and early growth of plants derived from durum wheat [T. turgidum L. ssp. durum (Desf) Husn.] with red smudge or black point/dark smudge symptoms were determined under controlled environmental conditions. Three soil gravimetric water content levels (1%, 5% and 20%) were used to simulate a range of field conditions which might occur in the spring in southern Saskatchewan. Plant emergence and growth were affected in a similar manner by the soil gravimetric water content, regardless of whether the seeds were affected by red smudge or black point/dark smudge. Lower soil gravimetric water content resulted in slower emergence of seedlings, reduced plant emergence and decreased development of above-ground and root tissue. Rate of emergence, number of plants emerged, and number of leaves were negatively affected by red smudge regardless of the soil gravimetric water content, while length of the longest seminal root and total plant dry weight were lower in the red smudge compared with the healthy treatment at the 20% soil gravimetric water content. A negative effect of black point/dark smudge on seedling emergence was observed only at the 1% soil gravimetric water content, while negative effects on the length of the longest leaf and total plant dry weight were observed in the black point/dark smudge treatment regardless of the soil gravimetric water content. We conclude that seed discolouration, especially red smudge, and soil gravimetric water content were important factors in the emergence and growth of durum wheat plants, with soil gravimetric water content compounding the negative effects of seed discolouration on plant emergence and growth.