The effect of raised bed culture on winter survival of ten pea
genotypes (Pisum sativum L.), differing in inherent cold hardiness
and growth habit, was studied under two climatic conditions: a moist
semi-maritime winter (Corvallis, Oregon) and a cold continental
winter (Weston, Oregon). An assessment of winter injury was based
on three indices: percent survival, plant weight, and a visually
assigned damage rating. Varying percentages of seven genotypes
survived at Corvallis and of six at Weston.
Planting on raised beds at Corvallis significantly increased the
mean percent survival and plant weight and decreased the mean damage
rating. Of two Corvallis planting dates, September 18 and
October 10, 1975, the latter had a significantly higher mean percent
survival and a lower mean damage rating.
At Weston, the mean percent survival was higher on ground
level plantings. Plant weight was not affected by planting method.
At this location there was a significant interaction between planting
method and genotype. Of the six surviving genotypes only the two
least hardy had significantly higher percent survival on ground level
plantings.
Controlled freezing tests between -2 and -10° C were conducted
on four genotypes, AW, WH2, INTl, and S4, to determine their relative
levels of inherent cold hardiness and cold acclimating ability.
An electrolyte leaching method of determining the extent of freezing
injury ranked the genotypes as follows, from most hardy to least:
AW = WH2 > INTl > S4. A visual estimation of damage ranked the
genotypes as follows: WH2 > AW > INTl > S4. In comparison, percent
survival in the field studies ranked the four genotypes: AW >
WH2 > INT1 > S4. Genotypes with a compact growth habit, AW
and WH2, acclimated [less than or equal to] 4° C, whereas those with an upright growth
habit, INTl and S4, acclimated 1-2° C
