Climatic variation in forage grasses. II. Germination, flowering and leaf development in Mediterranean populations of Phalaris tuberosa.
Eight populations covering the climatic range from Morocco and Israel to northern Italy and northern Greece differed little in germination characteristics at low temperatures (4-5° C.) but there were large differences in survival at high temperatures. The cold requirement for floral induction was closely related to the winter temperature of the place of origin. The optimum temperature for expansion of the leaf surface in all populations was about 24° C. day/19° C. night but leaf length and width responded differently to temperature changes. The relative growth rate in the early seedling stage was highly correlated with the rate of leaf expansion and was greatest in the Moroccan forms with a short growing season [cf. XXXV, 575].