Screening Peas for Winterhardiness Under Field and Laboratory Conditions¹

Abstract

Winter injury of the winter pea ( Pisum sativum subsp. arvense (L.) Poir) crop of northern Idaho causes severe losses. The development of cultivars with higher levels of winterhardiness would increase both the seed yield and area of adaptation of this crop. To evaluate techniques for determining winterhardiness in peas, 14 genotypes of winter‐hardy peas, and six genotypes of spring peas ( P. sativum L.), were screened in the field and laboratory. Trials were planted on three dates at Moscow, Idaho, and a single date at Bozeman, Mont., during the fall of 1976 and 1977. Seedlings were counted in both the fall and spring to determine the percent survival. At all planting dates and locations, the spring pea cultivars failed to survive the winter, indicating that spring types can be eliminated from segregating populations by fall planting. Three lines, ‘Romack’, ID 89‐1, and C8‐M‐23, appeared to be intermediate in winterhardiness and could be used as controls in future trials. Screening at −9 C in a programmable freezer eliminated all spring cultivars and produced differential survival among the winter‐hardy lines. Correlation coefficients between percent survival of the 13 winter‐hardy lines in the eight field environments and three test temperatures indicated that screening in the laboratory at −9 C successfully identified those lines with intermediate levels of winterhardiness. Fourteen lines of the P. sativum and four lines of the P. arvense USDA plant introduction collection had usable levels of winterhardiness in field trials at Moscow.