A 'Tiny' sorghum

In sorghum, a new gene designatedIn ty is responsible for an extreme reduction in the internodal length, producing Tiny plants. Internodal number is not affected but internodal length only. The wide divergence in internodal length is less graphic in its effect on leaf-sheath length. With reference to the leaf-blade, its length is more affected than its breadth. This gene does not affect the number of whorls on the earhead but has its effect in the panicle having a lesser number and shorter length of secondary panicle branches resulting in fewer spikelets per earhead. Glume size remains practically unaffected. So also ovary and stigma size. The anthers and filaments are reduced in size. The anthers are devoid of pollen. Dwarf plants are therefore usually sterile. Stray pollen grains could be found in some anthers and fertilization by them results in seeds giving true-breeding Tiny plants. The stigmas are very receptive and natural crossing is chronic. Plants heterozygous for the character are the main source of their reproduction. Factorin ty is a simple monogenic recessive toIn ty