Performance of crisphead lettuce cultivars and inbred lines in Santana da Vargem, Brazil, under winter conditions

Crisphead lettuce cultivars and inbred lines adapted to winter cultivation were evaluated in a trial of 42 cultivars, in Santana da Vargem, Minas Gerais State, Brazil. The experimental design was of randomized complete blocks, with 3 replications. Total fresh weight varied from 772 to 1268 g plant-1. The best performance was obtained from the inbred lines P1823-0014206-1 (1268 g plant-1) and P1823-0014325-3 (1232 g plant-1), which did not differ one from the other. The commercial fresh weight varied from 378 to 729 g plant-1 and a variation of 561 to 729 g plant-1 was obtained among statistically superior genotypes. The commercial head circumference varied from 35.6 to 49.2 cm. The inbred line with the biggest head circumference (P1823-0014325-3 with 49.2 cm) was statistically different from the other genotypes. Stem length varied from 1.9 to 4.9 cm, these results being considered acceptable for industrial processing. A variation including all degrees of scale notes was obtained for Bremia lactucae resistance, being considered resistant: SVR2210 (4.2); GX635 (4.2); P1843-1000148-1 (4.5); P1831-0015585-1 (4.5); P1831-0015338-1 (4.5); P1790-011945-1 (4.7); P1814-0013283-1 (4.7); P1843-1000697-1 (4.7); P1843-1000171-1 (4.7); P1843-1000179-2 (5.0); P1843-1000572-1 (5.0); P1692-0001843-1 (5.0); P1831-0015110-1 (5.0); P1831-0015060-1 (5.0); P1831-0015583-2 (5.0); P1831-0015309-1 (5.0); P1831-0015058-2 (5.0); P1823-0014206-1 (5.0); P1831-0015036-1 (5.0) and P1823-0014325-3 (5.0). The control cv. Raider presented high susceptibility to the disease.

Lactuca sativa L.; yield; competition; downy mildew resistance