Luminosity influences seed emergence in the initial development of papaya plants, being necessary the identification of the ideal irradiance level for plantule establishment and formation of vigorous seedlings. This study aimed to evaluate the seed emergence and seedlings vigor of four papaya genotypes, under different irradiance levels. Carica papaya L. seeds, from the Caliman 01 hybrid, Golden THB, triple hybrid and JS12 x Waimanalo hybrid genotypes, were evaluated under four irradiance levels (60 µmol m-2 s-1, 130 µmol m-2 s-1, 580 µmol m-2 s-1 and 1,200 µmol m-2 s-1). A completely randomized design, in a 4x4 split-plot scheme, with four replications, was used. The emergence percentage and speed index were evaluated. The seedlings were measured at 45 and 120 days after sowing (DAS), concerning root and shoot length and dry matter, being calculated the root/shoot ratio and absolute growth rate at 120 DAS. The full sun affected emergence, while the low irradiance affected seedling growth. The intermediate irradiance (130 µmol m-2 s-1 and 580 µmol m-2 s-1) was more suitable to the development of papaya seedlings up to 120 DAS. The Golden THB genotype was more sensitive to high irradiance, while the Caliman 01 and JS12 x Waimanalo hybrids tolerated the full sun condition.
Carica papaya L.; shading; seeds vigor
