Evaluation of Post-Flowering Drought Resistance Property of Ethiopian Sorghum Accessions Collected From the Drought Prone Northern Part of Ethiopia.

Abstract

Drought being the major factor limiting production of crops, developing crops that have the
mechanism to cope with such a drought prone production environments has become vital. Sorghum is
known for its post-flowering drought resistance property (stay-green). This study evaluated 165
sorghum landraces collected from draught prone areas of Ethiopia for this property. Based on visual
rating, 56 accessions were selected and further data was recorded on them. Twelve accessions were
identified that scored within the top 20 in at least three of the four traits which are positively
correlated (relative water content, chlorophyll content, proportion of green leaves remaining 30 days
after flowering, green leaf area at flowering). Nineteen accessions, in addition to showing these traits
also had higher extent of tillering, indicating the potential for dual purpose sorghum. The cluster
analysis grouped the accessions into four clusters. Based on the cluster mean, Cluster 4 and Cluster 2
showed superiority in most of the traits. Members of Cluster 1 had higher proportion of green leaves
remaining 30 days after flowering and the least proportion of green leaves remaining 15 days after
flowering; indicating that the accessions included in this cluster showed better performance through a
mechanism of slower rate of senescence or type B stay-green rather than delayed on set of
senescence. The cluster groups showed a clear pattern of association according to their collection
area; however, there were two distinct clusters (Cluster 3 and Cluster 4). The present result proposed
56 candidate stay-green sorghum accessions. The result also showed that these candidate materials
differ in the mechanism by which they attained the stay-green syndrome, indicating the possibility of
generating stay-green materials that would be different genetically and in their physiological
responses as well.