Winter wheat breeding for resistance to snow mold and cold hardiness 3. varietal differences of ecological characteristics on cold acclimation and their relationships to resistance
Amano, Y.; Osanai, S.I.
Bulletin of Hokkaido Prefectural Agricultural Experiment Stations 50: 83-97
In this paper we dealt with regional and varietal differences of growth increments and accumulations or depletions of substances from autumn to spring, correlations between reserve substances and resistance to freezing, Sclerotinia borealis, Typhula spp., and Fusarium nivale, and relationships of wintering type to ecological characteristics of 25 varieties. Twenty characters measured at 4 seasons before winter and after snow melt were analyzed. Dry weight, percentage dry matter, total carbohydrate, sugar, starch and proteinous N in the shoot of plant increased rapidly from autumn to early winter, and reached the maximum amount immediately after permanent snow. Soluble N phosphoric acid, K silic acid and ash decreased with the low temperature. Differences between locations, seasons, varieties, ans wintering types were significant in 16 characters measured before winter. Wheat plants in Kun-neppu showed less growth, much accumulation of carbohydrate and sugar in the fall, and less depletion of them in wintering than the ones in Iwamizawa [Japan]. Hardier varieties enter winter with greater carbohydrate reserves and maintained much carbohydrates after snow melt than susceptible ones. Correlations of reserve substances between before and after winter were highly significant except for reducing sugar and starch. Correlation coefficients of total carbohydrate between years was 0.751*** before winter and 0.767*** after snow melt at Kun-neppu. Highly significant correlations were found between freezing and osmotic value; S. borealis and phosphoric acid, lipid; Typhula spp., F. nivale and proteinous N total cabohydrate. Close relations were found among resistance to T. ishikaiensis, T. incarnata and F. nivale in degrees and in reserve substance contents. Varieties were classified into 4 groups based on the principal component analysis using 22 caracters of plant size and reserve substances. These groups were coincided very well with the previous 4 wintering types, namely, A, less-hardy; B, cold resistant; C. intermediate; D, snow endurable. Resistant varieties to Typhula spp. and F. nivale, C.I. 14106, P.I. 172582 and P.I. 173438 selected by Bruehl et al. accumulated carbohydrate much and more rapidly in the fall than the other varieties. Nevertheless, their contents of proteinous N, phosphoric acid, lipid, and osmotic value were very low.