Development of a Standard Artificial Freezing Technique for Evaluating Cold Resistance of Oats¹

Abstract

Synopsis A greenhouse and cold room technique is described which rates cold resistance of oat varieties in the same relative order as that in uniform hardiness experiments in the field. Of various factors influencing survival of seedlings, soil moisture content, temperature, length of cold treatment, and age of seedling had the greatest effect. Hardening treatment, thawing treatment and level of nutrition had small effects.

Moving beyond the Winter Hardiness Plateau in U.S. Oat Germplasm

“…These results suggest that mass selection was very effective in increasing the frequency of freeze‐tolerant genotypes in the segregating population. Studies have shown that controlled environment freeze resistance is a quantitative trait controlled by genes exhibiting additive effects and the trait had moderate to high heritability (Amirshahi and Patterson, 1956a; Muehlbauer et al, 1970). Our results support these conclusions and provide evidence of the ability of this controlled environment technique to alter gene frequencies rapidly under mass selection.…”

“…In addition, progress was slowed by the unpredictable occurrence of winters severe enough to kill tender genotypes and damage those of intermediate hardiness (Marshall, 1992). Early evaluations of oat in controlled environment tests designed to supplement field evaluations used juvenile whole‐plant assays (Murphy et al, 1937; Amirshahi and Patterson, 1956a, 1956b). Subsequent improvements in controlled environment techniques involved evaluation of individual lateral crown meristem tissue from which root and shoot regrowth is regenerated (Marshall, 1965).…”

Recovery after freezing in Avena sativa L., Lolium perenne L. and L. multiflorum Lam.

“…Although these mortality measurements can be quick and simple, some difficulty can exist in defining what constitutes survival. Estimates of percentage survival are made after periods of recovery varying from 7-10 d (Amirshahi & Patterson, 1956;Pfeifer & Kline, 1960), to 14 d (Arakeri & Schmid, 1949;Pomeroy & Fowler, 1973), 21 d (Fuller & Eagles, 1978) or 42 d (Rogers, Dunn & Nelson, 1977) but even after this length of time plants may be green but subsequently die (Dexter, 1956). It is not uncommon for initial recovery to occur as regrowth but for death to occur later (Anderson & Kiesselbach, 1934).…”