Characterization of culm morphology, anatomy and chemical composition of foxtail millet cultivars differing in lodging resistance

Abstract

SUMMARYLodging can be an important factor in limiting yield and quality of summer foxtail millet [Setaria italica (L.) P. Beauv.]. Although lodging resistance varies among different genotypes, direct selection for lodging resistance is difficult because of its sporadic occurrence in the field and inconsistency between years. A 2-year-field study was conducted with 35 summer foxtail millet cultivars or advanced breeding lines to determine the association between lodging resistance and culm morphology, anatomy and chemical composition. Path analyses indicated that stem-breaking strength had the most important effect on the lodging coefficient. The breaking strength of stem was associated with specific morphological properties of the culm, such as greater culm diameter and most importantly culm wall thickness. Width of sclerenchyma tissue, and the number and sheath width of the large vascular bundles were the major anatomical properties that influenced stem-breaking strength. The cellulose and lignin compositions of the culm had different effects on stem-breaking strength. Cultivars with smaller lodging coefficients contained higher levels of cellulose, but lower levels of lignin than the cultivars that were more prone to lodging. The findings from the present study provide useful information on lodging-associated traits in the culm that can be used as indicators for the improvement of lodging resistance in foxtail millet.