Morphological characteristics of wheat associated with high productivity

Abstract

Eight wheat (Triticum aestivum L.) cultivars including soft white spring, hard red spring, Canada Prairie Spring (CPS) and durum types were grown on rain-fed and irrigated land from 1987 to 1990 at Lethbridge, AB, to assess the relationship between yield components and radiation-use efficiency. Canopy reflectance measurements were used to estimate seasonal absorption of photosynthetically active radiation (APAR). At maturity, yield components including tillers per plant, heads per plant, kernels per head and kernel weight were determined. Whole-plant phytomass and grain yield were also determined. Harvest index was determined from the ratio of grain yield to whole-plant (excluding roots) phytomass and radiation-use efficiency (RUE) was calculated from the ratio of whole-plant phytomass to APAR. Significant grain yield differences confirmed that soft white and CPS wheats yielded more and responded more to irrigation than hard red or durum wheats. The yield components that were consistently different among cultivars were kernels per head and kernel weight which would be expected to increase if a consistent supply of assimilate was available during grain filling. Soft white and CPS wheats had higher harvest indices than the hard red or durum wheats, particularly under irrigation. Whole-plant phytomass was closely related to APAR and there were few differences among cultivars for RUE. There was no difference in RUE between rain-fed and irrigated treatments, indicating that there was probably no crop water stress on the rain-fed plots. RUE estimates for 1988 were lower than for the succeeding years, indicating an environmental or edaphic stress in that year.Key words: Remote sensing, radiation-use efficiency, yield components