Inheritance of grain size and shape in rice

Gene action governing the inheritance of kernel length, kernel breadth and length/breadth ratio were studied in three cross combinations viz., lET 13554/Ranga Joh 2, Pusa Basmati 1/Ranga Joha 2 and IR 64/Badshabhog. In all the three crosse, kernel breadth was under polygenic control along with few modifier genes. In the former two crosses, which had Ranga Joha 2 as common short bold grain parent, grain length and length ratio also followed the same pattern as that of kernel breadth. Whereas in the IR 64/Badshabhog cross the inheritance of grain length and shape was under monogenic control with long and slender grain types being dominant. In all the three crosses studied, transgressive segregation was observed particularly towards longer and slender grain size and confirming the role of minor genes in the inheritance of these characters