High yields of wheat are mainly obtained through a high level of nitrogen and irrigation supplementation.  However, excessive nitrogen and irrigation supplication increase the risk of lodging.  The main objectives of this work were to clarify the capacity of lodging resistance of wheat in response to nitrogen and irrigation, as well as to explore the effective ways of improving lodging resistance in a high-yield wheat cultivar. In this study, field experiments were conducted in the 2015–2016 and 2016–2017 growing seasons.  A wheat cultivar Jimai 22 (JM22), which is widely planted in the northern of Huang-Huai winter wheat region, was grown at Tai’an, Shandong Province, under three nitrogen rates and four irrigation treatments.  The lodging risk was increased with increased nitrogen rate, as indicated by increasing lodging index (LI) and lodging rate across both growing seasons.  With nitrogen increasing, the plant height, the basal internode length and the center of gravity height, which were positively correlated with LI, increased significantly.  While the density of the basal 2nd internode (for culm and leaf sheath) and cell wall component contents, which were negatively correlated with LI, decreased conspicuous along with nitrogen increased.  Increasing irrigation supplementation increased the 2nd internode culm wall thickness, breaking strength and leaf sheath density within limits which increased stem strength.  Among the treatments, nitrogen application at a rate of 240 kg ha^–1 and irrigation application at 600 m3 ha^–1 at both the jointing and anthesis stages resulted in the highest yield and strongest stem.  A suitable plant height ensures sufficient biomass for high yield, and higher stem stiffness, which was primarily attributed to thicker culm wall, greater density of the culm and leaf sheaths and higher cell wall component contents are the characteristics that should be taken into account to improving wheat lodging resistance.

The resistance in tomato plants to bacterial speck caused by Pseudomonas syringae pv. tomato is triggered by the interactions between the plant resistance protein Pto and the pathogen avirulence proteins AvrPto or AvrPtoB. Fen is a gene encoding closely related functional protein kinases as the Pto gene. To investigate the status of resistance to the pathogen and natural variation of Pto and Fen genes in tomato, 67 lines including 29 growing in China were subject to disease resistance evaluation and fenthion-sensitivity test. Alleles of Pto and Fen were amplified from genomic DNA of 25 tomato lines using polymerase chain reaction (PCR) and sequences were determined by sequencing the PCR products. The results indicated that none of the 29 cultivars/hybrids growing in China were resistant to bacterial speck race 0 strain DC3000. Seven of eight tomato lines resistant to DC3000 were also fenthion-sensitive. Analysis of deduced amino acid sequences identified three novel residue substitutions between Pto and pto, and one new substitution identified between Fen and fen. A PCR-based marker was developed and successfully used to select plants with resistance to DC3000.