Does the Attorney General have a duty to instruct a jury on a lesser included charge?

Finally, the Attorney General contends instructions on the lesser included offense were not required because there was no evidence the offense was less than that charged (e.g., People v. Osuna, 70 Cal.2d 759, 767, 76 Cal.Rptr. 462, 452 P.2d 678). At the time the instructions were given in this case, it appeared the trial court had a duty to instruct on a lesser included offense unless there was no evidence to support a conviction on the lesser charge (e.g., Sedeno, supra, 10 Cal.3d 703, 715, 720, 112 Cal.Rptr. 1, 518 P.2d 913). Subsequently, the duty has been modified so an instruction is required only when the evidence supporting conviction of the lesser included offense is substantial enough that a jury reasonably could have convicted on the lesser charge (Wickersham, supra, 32 Cal.3d 307, 324-325, 185 Cal.Rptr. 436, 650 P.2d 311).