Uncle Porn Kaset has written an open letter to Professor Rattapon Chatbanyong of Kasetsart University's Department of Horticulture, seeking guidance on successful guava cultivation amidst economic challenges. Professor Chatbanyong recommends specific guava varieties for commercial growth, emphasizes the importance of buying from reliable sources, and discusses the benefits of grafting and using rootstock resistant to root knot nematode. He also suggests farmers to taste potential cultivars before planting and to ensure good quality post-harvest. Uncle Porn Kaset concludes by stressing the need for ethical market practices and the importance of considering the origin of cultivars.