Poor soil fertility and recurrent drought are major constraints to maize production in the West African savanna. The development of maize cultivars with superior rooting system to absorb nitrogen and water efficiently from the soil is desirable. However. direct measurement of root characteristics for rapid selection of maize lines having tolerance to the two stresses is difficult. Vertical root-pulling strength. which has been shown to relate well to the rooting characteristics of the maize plant could be an alternative trait that can be used in improving the efficiency of selection of maize lines for tolerance to low-N stress and drought. This trait has effectively been used to select maize lines for resistance to corn root rot and lodging. Field evaluations were conducted during 2000 and 2001 to determine the root-pulling strength. yield. N-uptake and N-use of maize S1 lines derived from selected full-sib families from a Low-N tolerant population. There were significant differences in vertical root-pulling strength. N-uptake. N-use efficiency and yield among the maize breeding lines. Root- pulling strength positively correlated with N-uptake and maize yield. However. some S1 lines gave a higher grain yield despite low root-pulling strength. Other factors such as high numbers of cars per plant and high N-utilization efficiency were responsible for these yield increases. Because of the magnitude of the differences between S1 lines in root-pulling strength and the positive correlation of this trait with N-uptake. it can be used in selecting lines for variations in the rooting system and for high N uptake efficiency.

English

0410|AGRIS 0401|AL-Maize Program

Juan Carlos Mendieta

CIMMYT Publications Collection