Studies on Growth and Development of Tillers in Wheat : III. Developmental properties of tillers and their servival

Abstract

Tiller survival is a primary determinant of the number of tillers per plant. This study was conducted to examine how the tiller survival was affected by their own growth and development. Winter wheat (Triticum aestivum L.) plants, cv. Norin 61, were grown under dry (D, not irrigated), wet (W, irrigated) conditions in a vinyl-house and under field (F) conditions. Ten plants per plot were selected at random as observations, the emergence, survival and mortality of tillers were observed, and the leaf number of tillers, the differences of leaf number between tillers and their mother shoots were traced at intervals of 5-7 days from tiller appearance until mid-maturity. At the same period, 3-5 plants per plot were sampled weekly, and the leaf number, stem length, nodal root number and panicle development stage of main stem and tillers were measured. By comparing to the data of observed plants, the tillers of sampled plants were divided into the group to servive and the group destined to die prematurely. A comparison of the developmental properties of the two groups revealed that the rates of leaf emergence, stem elongation and panicle development of tillers to survive were consistent with the rates of their mother shoots, while the tillers to die showed reduced rates of leaf emergence, stem elongation and panicle development after the main stem elongation stage, and finally died.