Inheritance and interrelationship of grain clustering and panicle exsertion in Oryza sativa L.

Genetics of grain clustering was studied in eight crosses, of which five were studied for that of panicle exsertion up to F₃ generation. Interrelationship of genes governing these morphological characters was studied in F₂ of the five crosses and linkage was calculated on minimum discrepancy. The present study has yielded new genetical ratios 27: 37 and 81: 175 for grain clustering, and 3: 13, 45: 19 and 63: 193 for panicle exsertion reported for the first time. Further, a new linkage relationship between the genes Cl and Shp with C.o. = 36.30 in repulsion phase in the cross IR 36 x T 1061 is also reported. The genes identified in the present study for grain clustering are Cl, Cl_a, Cl_b, Cl_c and for panicle elCsertion Shp, Shp_a, Shp_b I-Shp/I-Shp_a and I-Shp_b.