In Situ Induction of Polyploidy in Guava (Psidium guajava']java L.)

Polyploid plants are noticeably superior in horticultural traits than diploid plants and could be utilized in future breeding programs. Hence, this study aimed to develop polyploidy guava progenies with superior horticultural traits in terms of yield and quality of fruit. In the present study, ploidy manipulation was attempted in P. guajava cv. 'Arka Kiran' using colchicine with three different methods (method 1-seed treatment, method 2-seedling meristem treatment, and method 3-seed treatment followed by seedling meristem treatment). A higher concentration of colchicine treatment decreased the percent seed germination and seedling survival. This investigation resulted in the generation of nine mixaploids (nuclear DNA range between 300-450) and three tetraploids (450-600) with method 1, 11 mixaploids and one tetraploid with method 2, and 14 mixaploids and four tetraploids with exceptionally one hexaploid (nuclear DNA range more than 600) with method 3. Across the different methods, maximum polyploidy induction efficiency (42.22%) was observed with method 2 and minimum was observed with method 1 (26.67%). This is the first report of in situ polyploidization in guava, providing valuable novel plant material for further breeding programmes.