A synoptic approach for crop loss assessment used to study wheat. V. Crop growth and yield

Abstract

As part of a general study of factors that affect wheat crops on Yorke Peninsula, S.A., growing and mature wheat plants were described in terms of morphological parameters and concentrations of elements in the tops. The measurements were taken 3 and 8 weeks after emergence of the crops, at anthesis and at maturity. The analyses of the morphological variables showed consistent patterns of variation in that, firstly, plants varied widely in their overall size, and secondly, that plants differed in the relative sizes of their tops and roots except at 8 weeks and at anthesis when the seminal root systems did not relate to the remainder of the plant. These two patterns of variation accounted for major portions of the variability, on average 88 % at 3 weeks, 95 % at 8 weeks and 88 % at anthesis, when the seminal root system was separated off in the latter two groups. The seminal root system and the element concentrations at 8 weeks and at anthesis were far less coherent sets of data. The results of these analyses provide the basis of the decisions concerning the information to go into the subsequent regression analyses for growth and yield of wheat.