Melt butter over medium heat; sauté onion, carrot, celery, and garlic in butter with curry powder until vegetables are tender (3-5 minutes).
Add the water, chicken, pepper, and poultry seasoning; bring to a boil.
Reduce heat to low, and simmer, covered, until chicken is tender (40 minutes).
Preheat oven to 350°F.
Remove the chicken and vegetables to a lightly greased 2-quart casserole or baking pan, and cook rice according to package directions in the broth remaining in the skillet (subbing broth for the water called for in the package directions; you'll need to add a cup or so of broth or water to get to the amount listed) (25 minutes).
In another skillet, melt butter, and sauté mushrooms and artichokes until tender (10 minutes).
Combine rice, mushroom/artichoke mixture, sour cream, soup, and salt with chicken/veg mixture in casserole.