On the frost damage of wheat plants occured at Tokorozawa district, Saitama prefecture in 1955

Abstract

In this paper, investigation on the frost damage of wheat plants which was found in Saitama Prefecture in April, 1955 is reported.The results of the investigation are as follows; -(1) This damage was found to be quite different from the frost damage which usually occurs in the North Kanto region. The latter causes death of young ears by frozen in wheat of high degree winter type. However, in the damage which we concern now, the death of young ears by frozen takes place in wheat of low degree winter type, and also the formation of ears on the lately developed tillers which usually are incapable of bearing, and the delaying of heading time were characteristic.(2) The death of young ears was caused by the low temperature (-2.4C) on the 5th of April. Ratio of dead (frozen) stem number to the all stems was estimated on the field and which was 68.3% in the severely damaged field, 48.1% in the intermediately damaged field, and 23.3% in the lightly damaged field.Such a difference in the damage was considered very likely as caused by the difference in the growth and developmental stage of the plants.(3) As the result of the damage, the growth of the suffered plants was changed. The change was apparently recognized with the number of lately formed stems, the stem length, the stem diameter and the heading time, etc. High correlation was found between the degree of damage and the changing of the above-mentioned morphological characters, as well as between each of these characters.(4) Effect of the damage of the yield of wheat was analyzed. The effect was apparently recognized in the decrease of complete grains, thus lowering the ratio of the complete grains to the whole, and also in the increase of quantity of incomplete grains and in the decrease of 1000 grains weight, etc. Actual decrease in yield was not found in the slightly damaged field, but decrease of about 30% and 70% in yield was found in the intermediately suffered and severely suffered field respectively. These defferences in the yield may be accounted for by the fact that the lately developed stems were capable of producing grains in compensation the decrease and this compensation differs with the defferent field.(5) Therefore it is likely possible to estimate the decreased amount of yield of wheat caused by the frost damage by the productivity of the lately developed stems action as a compensating factor.Significant correlations were found between the productivity and the number of days which the heading was delayed, length of stems, or diameter of stems, etc.