ABSTRACT
Seed disorders in which no recognizable pathogenic incitant is associated are known as physiogenic or nonpathogenic diseases. Nonpathogenic abnormalities are caused by disorders in the physiology of plants due to unfavorable environments including soil conditions. Aerial parts of plants, particularly growth and features of stem and leaves, are commonly affected by nonpathogenic factors. Climatic stresses, particularly humidity, low or high, cause visible symptoms in seeds of crop plants. A. J. Gane and A. J. Biddle observed the relationship between shape of seed and incidence of hollow heart in seed samples of cultivars Lincoln and Kelvedon Wonder. Physiological necrosis, rot, or spotted cotyledons, in seedlings of lettuce is a recognized abnormality. The high air humidity in the field at the time when the crop is close to maturity or high humidity during storage adversely affect the viability of the seed and also cause seedling abnormalities.
