Responses of yellow corn (Zea mays L.) inbreds to salinity

Two greenhouse experiments were conducted to assess the responses of yellow corn inbred lines to varying salt concentrations at early and late vegetative stages using hydroponics culture. In the first experiment, significant detrimental effects on young corn (Zea mays L.) plants from 19 inbred lines were apparent in terms of plant height, dry matter accumulation and survival when the plants were grown in saline medium (100 mMol NaCl). In contrast, chlorophyll content in plants generally increased under saline medium. Corn inbred lines varied in the degree of response to saline condition. Inbred lines that exhibited the highest tolerance and sensitivity to salt were advanced to the second experiment. The second experiment showed similar plant responses in terms of plant height, dry matter accumulation and survival when grown under increasingly saline medium at late vegetative stage. The tolerant inbred IYL-50 had the highest dry matter accumulation regardless of salinity level, while IYL-44 had the lowest. However, chlorophyll content also decreased with increasing salinity, in contrast to the results obtained from the first experiment. The inconsistency with the observation at early vegetative stage could be due to re-mobilization of nitrogen from the leaves (affecting the chlorophyll) as the plants shifted from vegetative to reproductive stage. Results showed that corn plants are more susceptible to salinity stress at early vegetative stage than at late vegetative to early reproductive stage. While the corn plants were found to be generally sensitive to salt stress, the observed differential degree of response could be used as a basis in selecting possible parent materials to develop salt tolerant corn varieties or hybrids.