Stem and canopy attributes that affect lodging resistance in lentil

Many lentil (Lens culinaris L.) cultivars currently grown in Western Canada are susceptible to lodging. The objective was to determine if plant traits associated with lodging but independent of environmental influences could be used for indirect selection of lodging resistance. For a range of canopy variation, eight genotypes were grown at three plant population densities in the field in 2001 and 2002 at five locations. Four unadapted genotypes (designated FLIP), varying in plant profile and stem stiffness, were compared with locally adapted cultivars. Lodging is a complex trait and was influenced by both genetic differences among the genotypes and environmental conditions. Large green market class cultivars had weak stems and lodged easily. As the canopy's ability to recover from crushing increased, lodging increased due to greater plant biomass. The greater the fiber content in the plant stems, the more biomass and more lodging occurred. Genotypic ranking of stem diameter was consistent across locations, and stem diameter may be used to indirectly select for lodging resistance. From regression analysis, stem diameter and lodging were described by branch number, recovery from canopy crushing, plant density, height, stem fiber content and lignin content; branch number, plant density and plant height were the most influential terms. For screening lodging resistance in crosses made from a lodging resistant genotype and a highly lodging susceptible genotype, selection of progeny with the smallest stem diameter should be the most lodging resistant, although yields will be reduced. Selection procedures would involve seeking large diameter stems but with similar stem traits of the small-stemmed FLIP lines.