Inheritance of morphological characters in sorghum

Sorghum (Sorghum bicolor) is an important food andfodder crop in India and the world. It has a number ofadvantages which have made it the traditional staplecereal crop in subsistence or low-resource agriculture inthe hot semi-arid regions. Morphological variants withdistinct phenotypic expression can be used to establishlinkages and for indirect selection if found associatedwith useful traits. However, for constructing linkagemaps, a sufficiently large number of distinct morphologicaltraits is required. Several morphological variants fordifferent plant parts, such as leaf, stem, spike, grainpeduncle, etc have been reported in sorghum (IBPGRand ICRISAT 1993). Among the many traits, brown andpithy leaf midrib, presence of awn, type of glumes in thepanicles and plant color, ie, anthocyanin pigmentation ofleaf sheath have been found to be useful as markers sincethey are associated with one or the other economicallyimportant traits such as increased fodder quality (brownmidrib) (Porter et al. 1978) and resistance to bird damage(presence of awns) (Kullaiswamy and Goud 1983). Closedglume type panicles have advantage over open typepanicles in offering resistance to grain mold infection(Murty 2000) and tan-colored plants are most preferredin seed industry as they exhibit immunity to variousfungal diseases (Melake-Berhan et al. 1996). A recentreport on the effects of plant color on agronomiccharacters of sorghum showed lower grain yields from agroup of tan hybrids compared to pigmented hybrids(Williams-Alanis et al. 1995). Further, such traits are moreimportant from the point of identification of cultivar,which is much needed in the present era of plant varietyprotection (Roy et al. 2004). In view of the importance ofthese characters in sorghum, an attempt has been made tostudy the inheritance of these characters using a set ofcultivars.