Screening under Low Plant Density Reinforces the Identification of Lentil Plants with Resistance to Fusarium Wilt

Abstract

Lentil (Lens culinaris Medikus) varieties resistant to Fusarium wilt (Fw) is a key issue in sustainable production systems. The effect of the plant density (PD) on screening lentil plants for resistance to Fw was studied for 4 yr. Single plants originating from 20 lentil varieties along with their seed composite were grown in a replicated‐21 honeycomb design under three PDs in a wilt‐sick plot. Plant densities were 3.2 plants m−2 (PDI), 12.8 plants m−2 (PDII), and 25.6 plants m−2 (PDIII). Ranking of lentil varieties was based on the percentage of dead wilted plants (%dwp). Two selection criteria, plant yield (PY) and plant yield potential (PYP), were applied for each PD within each year. Effectiveness of selection was determined as the number of the plants originating from the resistant varieties within the top 50 selected. The rate of dwp due to Fw increased as the PD decreased. The %dwp across years was 58, 45, and 18% for PDI, PDII, and PDIII, respectively. Significant changes were observed on the ranking and varietal description for Fw resistance among PDs. Effectiveness of selection was maximized under PDI, while application of the PYP indicated higher effectiveness values than PY, with a difference of 28% under PDI and 18% under PDII across years. It was concluded that screening under low PD is a valuable tool in identifying Fw‐resistant plants. Under this case, %dwp is an efficient and easy way to assess the resistance of elite lines, while application of the PYP criterion improves the effectiveness of the method when screening heterogeneous genetic material.