Selection of Drought Tolerant Bread Wheat Genotypes using Root Characteristics at Seedling Stage

Abstract

The following study was carried out to determine the suitability of the box technique for screening wheat for drought tolerance and the general characteristics of wheat seedlings related to resistance to drought. Three commercial wheat varieties, Duma, Kenya Mbweha and Mbuni which are tolerant, moderately tolerant, and susceptible respectively, were screened together with 3 lines R830, R831 and R748 which have been identified to show drought tolerance characters. The 6 were planted in boxes measuring 0.03m x 1m x 0.3m after this being determined as the best size for screening wheat seedlings. The rooting pattern of these genotypes was studied. Generally, drought resistant genotypes had more roots in the crown region with nodal and seminal roots concentrated between the soil surface and 70 cm deep. Susceptible genotypes had fewer roots in the crown region. Drought tolerant varieties were not necessarily deep rooted. Drought resistant genotypes had high absorptive surface area of up to 9.6 mm³ while susceptible ones had as low as 3.5 mm³. Root depth, total root length, relative absorptive surface area, number of roots, root spread, length of the longest root and root concentration were significantly different (P<0.05), among the genotypes tested. The root characters were reliable in identifying the different categories of the genotypes tested, and can be used as preliminary screening technique for drought tolerance. The box technique was found to reliably identify drought tolerant genotypes and is recommended for screening for drought tolerance in wheat.


Int. J. Agric. Rural Dev., 2003, 4: 9-15