INDUCTION OF POLYPLOIDY IN WATERMELON GENOTYPE WITH POWDERY MILDEW RESISTANCE (Podosphaera xanthii)

ABSTRACT Triploid watermelon is highly appreciated by the most demanding markets, and due to its small size, it ideal for consumption families. With growth in areas cultivated with seedless worldwide, there a demand development of tetraploid germplasm obtain triploid hybrids better agronomic performance. This study performed two tests induce polyploidy powdery mildew–resistant line developed Embrapa Semi-Arid, LDRO, under different colchicine concentrations application methods. In Experiment 1, seeds were treated (0.0%, 0.1%, 0.2%) 24 h 48 h. 2, 0.2% was applied methods: (a) directly on seed (MDS) without scarification, (b) radicle emission (MER), (c) at insertion point between hypocotyl root (MIHR), (d) seedling apex (MAP), (e) inverted (MHI). Chromosome count (cytogenetic analysis), number chloroplasts per pair guard cells, stomata, height, diameter measured. LDRO line, chromosomal duplication occurred some plant but not possible 100% plants. Colchicine (0.2%) mechanical scarification induced watermelon. The analysis identified level ploidy early, reducing plants needed be evaluated cytogenetics, which allowed us more accurately identify levels plant.