Abstract
Characteristics of deep root system of drought tolerance in cowpea (Vigna unguiculata (L.) Walp)
were evaluated by using ‘basket’ method and gene analysis. The ratio of the deep root number and
dry weight per total lateral roots in drought tolerant cultivar ‘205’ was significantly higher than those
of drought sensitive ‘555’. These results suggested that drought tolerant cultivar has deeper rooting
traits than the sensitive one. The drought tolerance of each cultivar was mainly regulated by BRrelated
gene, BZR1, which relates to lateral root development. Furthermore, the expression of genes
such as MSBP1 and Hy5 as well as BZR1 of lateral roots was significantly enhanced in the deep
roots compared to the shallow roots in the drought tolerant cultivar. Taken together, the deep root
system in cowpea may contribute to its drought tolerance through enhanced water uptake from deep
soil layer.
