Wheat Root Systems, Genetics and Methodology for Evaluation of Root Characteristics: A Review

The wheat root system varies considerably in vertical and horizontal distribution in soil depending on environmental conditions and approximately 65% of total root dry weight is in the 0 to 30 cm soil layer. Wheat root growth reaches maximum extension in the flowering stage. After flowering stage, root growth rates decrease or stop depending upon water and fertilizer availability. Selection for enhanced root traits may play a significant role in increasing yield of wheat varieties grown in marginal environments Root growth in the soil profile depends on conditions such as wheat genotype, available water, physical and chemical properties of soil, environmental condition, fertilization, and other biotic and abiotic factors. Researchers generally have avoided study of root systems because root research requires a lot of time and intensive labor. Thus little is known about the genetics of wheat root traits and genetic improvement of root systems is not a common objective of plant breeding programs. There are many methods available to select for improved root traits suitable for selection under greenhouse or field conditions. Additional modern techniques have been developed, that substitute technology for labor, but with the disadvantage of additional expense. Physiologists and breeders involved in the selection of new varieties should increasingly turn to root analysis methods to select for wheat varieties with enhanced root growth and agronomic yield.