Study of some characters related to lodging resistance and yield under different nitrogen levels in bread wheat.

摘要

An experiment was conducted in Egypt during 1998/99-1999/2000 seasons on 9 bread wheat genotypes and their non-reciprocal F1s to evaluate the traits related to lodging resistance under 3 N levels (50, 75 and 100 kg/feddan). The mean plant height andsecond internode length over all the genotypes increased as the N level increased. Stem diameter, dry weight of the second internode and stem wall thickness also showed significant increase with increasing N level up to 75 kg/ha. The 100 kg N treatmentproduced the highest plant height/stem diameter ratio (28.81) and the lowest diameter/length ratio (0.406) for the second internode. The lodging percentage increased with the increase of N level. The correlation between lodging and related morphologicaltraits for each N level indicates that plant height was positively and highly significantly correlated with the second internode length. The value of the correlation was almost the same under all N levels which indicates that the correlation is mostly controlled by genetic factors rather than environmental factors i.e. N levels. For the correlation with second internode diameter, the correlation was negative and highly significant with an increase of the value as N level increased. The dominance gene effects accounted for most of the variation of the studied traits with (H1/D)1/2 value of more than one except for plant height. The genotype Sakha 8 was the best general combiner for traits related to lodging resistance with high grain yield/plant. The cross combination (Sakha 8 x Chenab 70) showed high specific combining ability for all the studied traits.