Morphological parameters of stem lodging resistance in accessions of hulless oats collection

Morphological parameters of stem in 213 accessions of naked oats (Avena nuda L.) of different ecological and geographic origin were studied under conditions of northern forest-steppe of the Tyumen region in connection with breeding for lodging resistance. Relation between plants height and some morphological parameters of stem with lodging was ambiguous. The negative correlation between lodging resistance with plant height (r = -0.34 ... -0.77), with the length of the top (r = -0.16 ... -0.74) and the first interstices (r = -0.67 ... -0.86) was marked. It was found that the formation of lodging resistance was determined not by the size of stem parts but their ratio. It is noted that the higher the ratio of length to diameter of the first and second interstices the stronger the propensity to lodging (r1 = -0.39 ... -0.98; r2 = -0.62 ... -0.97). A close negative correlation was found between lodging resistance and ratio of length to diameter of straw of the first interstices (r = -0.70 ... -0.91). Sustainability indexes were used to evaluate the initial material, which take into account the ratio of the individual parts of the stem and indexes evaluating the ratio of productive and vegetative parts. It was found that the value of index, taking into account the ratio of the length of internodes to their diameter, the length of straw to its diameter and length of internodes in varieties with high lodging resistance was significantly lower than that of lodge accessions. At the same time, lodging resistant varieties (in compare with a weakly resistant) had a higher value of the index, taking into account the set of morphological parameters of the stem and panicle and evaluating the ratio of productive and vegetative parts. A comparative study of initial material the use of complex of stem morphological traits complements visual assessment of lodging resistance and allowed to characterize the studied accessions for this indicator more fully