Virus-free garlic: yield and commercial classification as a function of plant spacing and seed size

Studies on the interaction between garlic plant density and virus-free seed size are scarce in Brazil. Thus, this study was installed to evaluate the effect of plant spacing and seed size on garlic traits and yield for infected and virus-free bulbs. Treatments were arranged in a randomized block design and 2x5x3 factorial combination [infected and virus-free bulbs, five plant spacings (210, 260, 300, 360, and 390 cm2 per plant), and three bulbous seed sizes (sieve one, two, and three)]. The highest bulb yield was observed for virus-free seeds at a plant spacing of 390 cm2 plant-1, while the highest commercial yield was verified for 210 cm2 plant-1 spacing. The combination of virus-free seeds, larger bulbs, and 332 cm2 plant-1 spacing promoted the highest leaf area index. For virus-free garlic, lower plant densities resulted in higher yields and garlic bulb quality. The best option for higher yields and improved commercial quality bulbs was the use of medium-sized virus-free bulbils at a plant density of about 300 thousand plants ha-1.