Phenotypes and the onset of competition in spring barley stands of one genotype : daylength and density effects on tillering

摘要: Abstract Understanding the genotype–environment interactions requires a distinction between two effects of environment on plants given genotype: achievement growth throughout their whole life and prior determination potentials. Spring barley seeds from same seed lot were sown at end winter three altitudes: 320 m a.s.l. (end February), 880 (beginning April) 1120 May), May lowest site, in sparse dense stands with without nitrogen fertilization. This experimental design natural conditions gave differences initial daylengths (12, 14 more than 15 h) that must modify potentials, different levels competition, acting achievement. The tillering patterns measured individual plants. tillers axils first second leaf lacking many growing long day treatments stands, this increased up to 70 90% stands. seems be due far-red signals seedlings emerging which induce floral development, before any competition can occur. Afterwards, cessation as result onset was delayed markedly during stem elongation established daylengths. Such phenotypes showed strongly reduced